Merge the gup_flags cleanups from Lorenzo Stoakes:
"This patch series adjusts functions in the get_user_pages* family such
that desired FOLL_* flags are passed as an argument rather than
implied by flags.
The purpose of this change is to make the use of FOLL_FORCE explicit
so it is easier to grep for and clearer to callers that this flag is
being used. The use of FOLL_FORCE is an issue as it overrides missing
VM_READ/VM_WRITE flags for the VMA whose pages we are reading
from/writing to, which can result in surprising behaviour.
The patch series came out of the discussion around commit 38e0885465
("mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing"),
which addressed a BUG_ON() being triggered when a page was faulted in
with PROT_NONE set but having been overridden by FOLL_FORCE.
do_numa_page() was run on the assumption the page _must_ be one marked
for NUMA node migration as an actual PROT_NONE page would have been
dealt with prior to this code path, however FOLL_FORCE introduced a
situation where this assumption did not hold.
See
https://marc.info/?l=linux-mm&m=147585445805166
for the patch proposal"
Additionally, there's a fix for an ancient bug related to FOLL_FORCE and
FOLL_WRITE by me.
[ This branch was rebased recently to add a few more acked-by's and
reviewed-by's ]
* gup_flag-cleanups:
mm: replace access_process_vm() write parameter with gup_flags
mm: replace access_remote_vm() write parameter with gup_flags
mm: replace __access_remote_vm() write parameter with gup_flags
mm: replace get_user_pages_remote() write/force parameters with gup_flags
mm: replace get_user_pages() write/force parameters with gup_flags
mm: replace get_vaddr_frames() write/force parameters with gup_flags
mm: replace get_user_pages_locked() write/force parameters with gup_flags
mm: replace get_user_pages_unlocked() write/force parameters with gup_flags
mm: remove write/force parameters from __get_user_pages_unlocked()
mm: remove write/force parameters from __get_user_pages_locked()
mm: remove gup_flags FOLL_WRITE games from __get_user_pages()
This removes the 'write' argument from access_process_vm() and replaces
it with 'gup_flags' as use of this function previously silently implied
FOLL_FORCE, whereas after this patch callers explicitly pass this flag.
We make this explicit as use of FOLL_FORCE can result in surprising
behaviour (and hence bugs) within the mm subsystem.
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes the 'write' and 'force' from get_user_pages_remote() and
replaces them with 'gup_flags' to make the use of FOLL_FORCE explicit in
callers as use of this flag can result in surprising behaviour (and
hence bugs) within the mm subsystem.
Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A scheduler performance regression has been reported by Joseph Salisbury,
which he bisected back to:
3d30544f02 ("sched/fair: Apply more PELT fixes)
The regression triggers when several levels of task groups are involved
(read: SystemD) and cpu_possible_mask != cpu_present_mask.
The root cause is that group entity's load (tg_child->se[i]->avg.load_avg)
is initialized to scale_load_down(se->load.weight). During the creation of
a child task group, its group entities on possible CPUs are attached to
parent's cfs_rq (tg_parent) and their loads are added to the parent's load
(tg_parent->load_avg) with update_tg_load_avg().
But only the load on online CPUs will then be updated to reflect real load,
whereas load on other CPUs will stay at the initial value.
The result is a tg_parent->load_avg that is higher than the real load, the
weight of group entities (tg_parent->se[i]->load.weight) on online CPUs is
smaller than it should be, and the task group gets a less running time than
what it could expect.
( This situation can be detected with /proc/sched_debug. The ".tg_load_avg"
of the task group will be much higher than sum of ".tg_load_avg_contrib"
of online cfs_rqs of the task group. )
The load of group entities don't have to be intialized to something else
than 0 because their load will increase when an entity is attached.
Reported-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@vger.kernel.org> # 4.8.x
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: joonwoop@codeaurora.org
Fixes: 3d30544f02 ("sched/fair: Apply more PELT fixes)
Link: http://lkml.kernel.org/r/1476881123-10159-1-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull timer fixlet from Ingo Molnar:
"Remove an unused variable"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
alarmtimer: Remove unused but set variable
Pull scheduler fix from Ingo Molnar:
"Fix a crash that can trigger when racing with CPU hotplug: we didn't
use sched-domains data structures carefully enough in select_idle_cpu()"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Fix sched domains NULL dereference in select_idle_sibling()
Pull misc fixes from Ingo Molnar:
"A CPU hotplug debuggability fix and three objtool false positive
warnings fixes for new GCC6 code generation patterns"
* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
cpu/hotplug: Use distinct name for cpu_hotplug.dep_map
objtool: Skip all "unreachable instruction" warnings for gcov kernels
objtool: Improve rare switch jump table pattern detection
objtool: Support '-mtune=atom' stack frame setup instruction
Remove the set but unused variable base in alarm_clock_get to fix the
following warning when building with 'W=1':
kernel/time/alarmtimer.c: In function ‘alarm_timer_create’:
kernel/time/alarmtimer.c:545:21: warning: variable ‘base’ set but not used [-Wunused-but-set-variable]
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161017094702.10873-1-tklauser@distanz.ch
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Use distinctive name for cpu_hotplug.dep_map to avoid the actual
cpu_hotplug.lock appearing as cpu_hotplug.lock#2 in lockdep splats.
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Gautham R . Shenoy <ego@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: intel-gfx@lists.freedesktop.org
Cc: trivial@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
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Merge tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugins update from Kees Cook:
"This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot
time as possible, hoping to capitalize on any possible variation in
CPU operation (due to runtime data differences, hardware differences,
SMP ordering, thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example
for how to manipulate kernel code using the gcc plugin internals"
* tag 'gcc-plugins-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
latent_entropy: Mark functions with __latent_entropy
gcc-plugins: Add latent_entropy plugin
Pull cgroup updates from Tejun Heo:
- tracepoints for basic cgroup management operations added
- kernfs and cgroup path formatting functions updated to behave in the
style of strlcpy()
- non-critical bug fixes
* 'for-4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
blkcg: Unlock blkcg_pol_mutex only once when cpd == NULL
cgroup: fix error handling regressions in proc_cgroup_show() and cgroup_release_agent()
cpuset: fix error handling regression in proc_cpuset_show()
cgroup: add tracepoints for basic operations
cgroup: make cgroup_path() and friends behave in the style of strlcpy()
kernfs: remove kernfs_path_len()
kernfs: make kernfs_path*() behave in the style of strlcpy()
kernfs: add dummy implementation of kernfs_path_from_node()
This affectively reverts commit 377ccbb483 ("Makefile: Mute warning
for __builtin_return_address(>0) for tracing only") because it turns out
that it really isn't tracing only - it's all over the tree.
We already also had the warning disabled separately for mm/usercopy.c
(which this commit also removes), and it turns out that we will also
want to disable it for get_lock_parent_ip(), that is used for at least
TRACE_IRQFLAGS. Which (when enabled) ends up being all over the tree.
Steven Rostedt had a patch that tried to limit it to just the config
options that actually triggered this, but quite frankly, the extra
complexity and abstraction just isn't worth it. We have never actually
had a case where the warning is actually useful, so let's just disable
it globally and not worry about it.
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Previously hung_task_panic would not be respected if enabled after
hung_task_warnings had already been decremented to 0.
Permit the kernel to panic if hung_task_panic is enabled after
hung_task_warnings has already been decremented to 0 and another task
hangs for hung_task_timeout_secs seconds.
Check if hung_task_panic is enabled so we don't return prematurely, and
check if hung_task_warnings is non-zero so we don't print the warning
unnecessarily.
[akpm@linux-foundation.org: fix off-by-one]
Link: http://lkml.kernel.org/r/1473450214-4049-1-git-send-email-jsiddle@redhat.com
Signed-off-by: John Siddle <jsiddle@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch allows to make kthread worker freezable via a new @flags
parameter. It will allow to avoid an init work in some kthreads.
It currently does not affect the function of kthread_worker_fn()
but it might help to do some optimization or fixes eventually.
I currently do not know about any other use for the @flags
parameter but I believe that we will want more flags
in the future.
Finally, I hope that it will not cause confusion with @flags member
in struct kthread. Well, I guess that we will want to rework the
basic kthreads implementation once all kthreads are converted into
kthread workers or workqueues. It is possible that we will merge
the two structures.
Link: http://lkml.kernel.org/r/1470754545-17632-12-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are situations when we need to modify the delay of a delayed kthread
work. For example, when the work depends on an event and the initial delay
means a timeout. Then we want to queue the work immediately when the event
happens.
This patch implements kthread_mod_delayed_work() as inspired workqueues.
It cancels the timer, removes the work from any worker list and queues it
again with the given timeout.
A very special case is when the work is being canceled at the same time.
It might happen because of the regular kthread_cancel_delayed_work_sync()
or by another kthread_mod_delayed_work(). In this case, we do nothing and
let the other operation win. This should not normally happen as the caller
is supposed to synchronize these operations a reasonable way.
Link: http://lkml.kernel.org/r/1470754545-17632-11-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are going to use kthread workers more widely and sometimes we will need
to make sure that the work is neither pending nor running.
This patch implements cancel_*_sync() operations as inspired by
workqueues. Well, we are synchronized against the other operations via
the worker lock, we use del_timer_sync() and a counter to count parallel
cancel operations. Therefore the implementation might be easier.
First, we check if a worker is assigned. If not, the work has newer been
queued after it was initialized.
Second, we take the worker lock. It must be the right one. The work must
not be assigned to another worker unless it is initialized in between.
Third, we try to cancel the timer when it exists. The timer is deleted
synchronously to make sure that the timer call back is not running. We
need to temporary release the worker->lock to avoid a possible deadlock
with the callback. In the meantime, we set work->canceling counter to
avoid any queuing.
Fourth, we try to remove the work from a worker list. It might be
the list of either normal or delayed works.
Fifth, if the work is running, we call kthread_flush_work(). It might
take an arbitrary time. We need to release the worker-lock again. In the
meantime, we again block any queuing by the canceling counter.
As already mentioned, the check for a pending kthread work is done under a
lock. In compare with workqueues, we do not need to fight for a single
PENDING bit to block other operations. Therefore we do not suffer from
the thundering storm problem and all parallel canceling jobs might use
kthread_flush_work(). Any queuing is blocked until the counter gets zero.
Link: http://lkml.kernel.org/r/1470754545-17632-10-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are going to use kthread_worker more widely and delayed works
will be pretty useful.
The implementation is inspired by workqueues. It uses a timer to queue
the work after the requested delay. If the delay is zero, the work is
queued immediately.
In compare with workqueues, each work is associated with a single worker
(kthread). Therefore the implementation could be much easier. In
particular, we use the worker->lock to synchronize all the operations with
the work. We do not need any atomic operation with a flags variable.
In fact, we do not need any state variable at all. Instead, we add a list
of delayed works into the worker. Then the pending work is listed either
in the list of queued or delayed works. And the existing check of pending
works is the same even for the delayed ones.
A work must not be assigned to another worker unless reinitialized.
Therefore the timer handler might expect that dwork->work->worker is valid
and it could simply take the lock. We just add some sanity checks to help
with debugging a potential misuse.
Link: http://lkml.kernel.org/r/1470754545-17632-9-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Nothing currently prevents a work from queuing for a kthread worker when
it is already running on another one. This means that the work might run
in parallel on more than one worker. Also some operations are not
reliable, e.g. flush.
This problem will be even more visible after we add kthread_cancel_work()
function. It will only have "work" as the parameter and will use
worker->lock to synchronize with others.
Well, normally this is not a problem because the API users are sane.
But bugs might happen and users also might be crazy.
This patch adds a warning when we try to insert the work for another
worker. It does not fully prevent the misuse because it would make the
code much more complicated without a big benefit.
It adds the same warning also into kthread_flush_work() instead of the
repeated attempts to get the right lock.
A side effect is that one needs to explicitly reinitialize the work if it
must be queued into another worker. This is needed, for example, when the
worker is stopped and started again. It is a bit inconvenient. But it
looks like a good compromise between the stability and complexity.
I have double checked all existing users of the kthread worker API and
they all seems to initialize the work after the worker gets started.
Just for completeness, the patch adds a check that the work is not already
in a queue.
The patch also puts all the checks into a separate function. It will be
reused when implementing delayed works.
Link: http://lkml.kernel.org/r/1470754545-17632-8-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The current kthread worker users call flush() and stop() explicitly.
This function does the same plus it frees the kthread_worker struct
in one call.
It is supposed to be used together with kthread_create_worker*() that
allocates struct kthread_worker.
Link: http://lkml.kernel.org/r/1470754545-17632-7-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Kthread workers are currently created using the classic kthread API,
namely kthread_run(). kthread_worker_fn() is passed as the @threadfn
parameter.
This patch defines kthread_create_worker() and
kthread_create_worker_on_cpu() functions that hide implementation details.
They enforce using kthread_worker_fn() for the main thread. But I doubt
that there are any plans to create any alternative. In fact, I think that
we do not want any alternative main thread because it would be hard to
support consistency with the rest of the kthread worker API.
The naming and function of kthread_create_worker() is inspired by the
workqueues API like the rest of the kthread worker API.
The kthread_create_worker_on_cpu() variant is motivated by the original
kthread_create_on_cpu(). Note that we need to bind per-CPU kthread
workers already when they are created. It makes the life easier.
kthread_bind() could not be used later for an already running worker.
This patch does _not_ convert existing kthread workers. The kthread
worker API need more improvements first, e.g. a function to destroy the
worker.
IMPORTANT:
kthread_create_worker_on_cpu() allows to use any format of the worker
name, in compare with kthread_create_on_cpu(). The good thing is that it
is more generic. The bad thing is that most users will need to pass the
cpu number in two parameters, e.g. kthread_create_worker_on_cpu(cpu,
"helper/%d", cpu).
To be honest, the main motivation was to avoid the need for an empty
va_list. The only legal way was to create a helper function that would be
called with an empty list. Other attempts caused compilation warnings or
even errors on different architectures.
There were also other alternatives, for example, using #define or
splitting __kthread_create_worker(). The used solution looked like the
least ugly.
Link: http://lkml.kernel.org/r/1470754545-17632-6-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kthread_create_on_node() implements a bunch of logic to create the
kthread. It is already called by kthread_create_on_cpu().
We are going to extend the kthread worker API and will need to call
kthread_create_on_node() with va_list args there.
This patch does only a refactoring and does not modify the existing
behavior.
Link: http://lkml.kernel.org/r/1470754545-17632-5-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kthread_create_on_cpu() was added by the commit 2a1d446019
("kthread: Implement park/unpark facility"). It is currently used only
when enabling new CPU. For this purpose, the newly created kthread has to
be parked.
The CPU binding is a bit tricky. The kthread is parked when the CPU has
not been allowed yet. And the CPU is bound when the kthread is unparked.
The function would be useful for more per-CPU kthreads, e.g.
bnx2fc_thread, fcoethread. For this purpose, the newly created kthread
should stay in the uninterruptible state.
This patch moves the parking into smpboot. It binds the thread already
when created. Then the function might be used universally. Also the
behavior is consistent with kthread_create() and kthread_create_on_node().
Link: http://lkml.kernel.org/r/1470754545-17632-4-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
A good practice is to prefix the names of functions by the name
of the subsystem.
The kthread worker API is a mix of classic kthreads and workqueues. Each
worker has a dedicated kthread. It runs a generic function that process
queued works. It is implemented as part of the kthread subsystem.
This patch renames the existing kthread worker API to use
the corresponding name from the workqueues API prefixed by
kthread_:
__init_kthread_worker() -> __kthread_init_worker()
init_kthread_worker() -> kthread_init_worker()
init_kthread_work() -> kthread_init_work()
insert_kthread_work() -> kthread_insert_work()
queue_kthread_work() -> kthread_queue_work()
flush_kthread_work() -> kthread_flush_work()
flush_kthread_worker() -> kthread_flush_worker()
Note that the names of DEFINE_KTHREAD_WORK*() macros stay
as they are. It is common that the "DEFINE_" prefix has
precedence over the subsystem names.
Note that INIT() macros and init() functions use different
naming scheme. There is no good solution. There are several
reasons for this solution:
+ "init" in the function names stands for the verb "initialize"
aka "initialize worker". While "INIT" in the macro names
stands for the noun "INITIALIZER" aka "worker initializer".
+ INIT() macros are used only in DEFINE() macros
+ init() functions are used close to the other kthread()
functions. It looks much better if all the functions
use the same scheme.
+ There will be also kthread_destroy_worker() that will
be used close to kthread_cancel_work(). It is related
to the init() function. Again it looks better if all
functions use the same naming scheme.
+ there are several precedents for such init() function
names, e.g. amd_iommu_init_device(), free_area_init_node(),
jump_label_init_type(), regmap_init_mmio_clk(),
+ It is not an argument but it was inconsistent even before.
[arnd@arndb.de: fix linux-next merge conflict]
Link: http://lkml.kernel.org/r/20160908135724.1311726-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/1470754545-17632-3-git-send-email-pmladek@suse.com
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Patch series "kthread: Kthread worker API improvements"
The intention of this patchset is to make it easier to manipulate and
maintain kthreads. Especially, I want to replace all the custom main
cycles with a generic one. Also I want to make the kthreads sleep in a
consistent state in a common place when there is no work.
This patch (of 11):
A good practice is to prefix the names of functions by the name of the
subsystem.
This patch fixes the name of probe_kthread_data(). The other wrong
functions names are part of the kthread worker API and will be fixed
separately.
Link: http://lkml.kernel.org/r/1470754545-17632-2-git-send-email-pmladek@suse.com
Signed-off-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Borislav Petkov <bp@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As of Android N, SECCOMP is required. Without it, we will get
mediaextractor error:
E /system/bin/mediaextractor: libminijail: prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER): Invalid argument
Link: http://lkml.kernel.org/r/20160908185934.18098-3-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Android won't boot without SELinux enabled, so make it the default.
Link: http://lkml.kernel.org/r/20160908185934.18098-2-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CONFIG_MD is in recommended, but other dependent options like DM_CRYPT and
DM_VERITY options are in base. The result is the options in base don't
get enabled when applying both base and recommended fragments. Move all
the options to recommended.
Link: http://lkml.kernel.org/r/20160908185934.18098-1-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: John Stultz <john.stultz@linaro.org>
Cc: Amit Pundir <amit.pundir@linaro.org>
Cc: Dmitry Shmidt <dimitrysh@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Relay avoids calling wake_up_interruptible() for doing the wakeup of
readers/consumers, waiting for the generation of new data, from the
context of a process which produced the data. This is apparently done to
prevent the possibility of a deadlock in case Scheduler itself is is
generating data for the relay, after acquiring rq->lock.
The following patch used a timer (to be scheduled at next jiffy), for
delegating the wakeup to another context.
commit 7c9cb38302
Author: Tom Zanussi <zanussi@comcast.net>
Date: Wed May 9 02:34:01 2007 -0700
relay: use plain timer instead of delayed work
relay doesn't need to use schedule_delayed_work() for waking readers
when a simple timer will do.
Scheduling a plain timer, at next jiffies boundary, to do the wakeup
causes a significant wakeup latency for the Userspace client, which makes
relay less suitable for the high-frequency low-payload use cases where the
data gets generated at a very high rate, like multiple sub buffers getting
filled within a milli second. Moreover the timer is re-scheduled on every
newly produced sub buffer so the timer keeps getting pushed out if sub
buffers are filled in a very quick succession (less than a jiffy gap
between filling of 2 sub buffers). As a result relay runs out of sub
buffers to store the new data.
By using irq_work it is ensured that wakeup of userspace client, blocked
in the poll call, is done at earliest (through self IPI or next timer
tick) enabling it to always consume the data in time. Also this makes
relay consistent with printk & ring buffers (trace), as they too use
irq_work for deferred wake up of readers.
[arnd@arndb.de: select CONFIG_IRQ_WORK]
Link: http://lkml.kernel.org/r/20160912154035.3222156-1-arnd@arndb.de
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1472906487-1559-1-git-send-email-akash.goel@intel.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Akash Goel <akash.goel@intel.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Daniel Walker reported problems which happens when
crash_kexec_post_notifiers kernel option is enabled
(https://lkml.org/lkml/2015/6/24/44).
In that case, smp_send_stop() is called before entering kdump routines
which assume other CPUs are still online. As the result, for x86, kdump
routines fail to save other CPUs' registers and disable virtualization
extensions.
To fix this problem, call a new kdump friendly function,
crash_smp_send_stop(), instead of the smp_send_stop() when
crash_kexec_post_notifiers is enabled. crash_smp_send_stop() is a weak
function, and it just call smp_send_stop(). Architecture codes should
override it so that kdump can work appropriately. This patch only
provides x86-specific version.
For Xen's PV kernel, just keep the current behavior.
NOTES:
- Right solution would be to place crash_smp_send_stop() before
__crash_kexec() invocation in all cases and remove smp_send_stop(), but
we can't do that until all architectures implement own
crash_smp_send_stop()
- crash_smp_send_stop()-like work is still needed by
machine_crash_shutdown() because crash_kexec() can be called without
entering panic()
Fixes: f06e5153f4 (kernel/panic.c: add "crash_kexec_post_notifiers" option)
Link: http://lkml.kernel.org/r/20160810080948.11028.15344.stgit@sysi4-13.yrl.intra.hitachi.co.jp
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Reported-by: Daniel Walker <dwalker@fifo99.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Daniel Walker <dwalker@fifo99.com>
Cc: Xunlei Pang <xpang@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <david.daney@cavium.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: "Steven J. Hill" <steven.hill@cavium.com>
Cc: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On __ptrace_detach(), called from do_exit()->exit_notify()->
forget_original_parent()->exit_ptrace(), the TIF_SYSCALL_TRACE in
thread->flags of the tracee is not cleared up. This results in the
tracehook_report_syscall_* being called (though there's no longer a tracer
listening to that) upon its further syscalls.
Example scenario - attach "strace" to a running process and kill it (the
strace) with SIGKILL. You'll see that the syscall trace hooks are still
being called.
The clearing of this flag should be moved from ptrace_detach() to
__ptrace_detach().
Link: http://lkml.kernel.org/r/1472759493-20554-1-git-send-email-alnovak@suse.cz
Signed-off-by: Ales Novak <alnovak@suse.cz>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
asm-generic headers are generic implementations for architecture specific
code and should not be included by common code. Thus use the asm/ version
of sections.h to get at the linker sections.
Link: http://lkml.kernel.org/r/1473602302-6208-1-git-send-email-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit:
10e2f1acd0 ("sched/core: Rewrite and improve select_idle_siblings()")
... improved select_idle_sibling(), but also triggered a regression (crash)
during CPU-hotplug:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000078
IP: [<ffffffffb10cd332>] select_idle_sibling+0x1c2/0x4f0
Call Trace:
<IRQ>
select_task_rq_fair+0x749/0x930
? select_task_rq_fair+0xb4/0x930
? __lock_is_held+0x54/0x70
try_to_wake_up+0x19a/0x5b0
default_wake_function+0x12/0x20
autoremove_wake_function+0x12/0x40
__wake_up_common+0x55/0x90
__wake_up+0x39/0x50
wake_up_klogd_work_func+0x40/0x60
irq_work_run_list+0x57/0x80
irq_work_run+0x2c/0x30
smp_irq_work_interrupt+0x2e/0x40
irq_work_interrupt+0x96/0xa0
<EOI>
? _raw_spin_unlock_irqrestore+0x45/0x80
try_to_wake_up+0x4a/0x5b0
wake_up_state+0x10/0x20
__kthread_unpark+0x67/0x70
kthread_unpark+0x22/0x30
cpuhp_online_idle+0x3e/0x70
cpu_startup_entry+0x6a/0x450
start_secondary+0x154/0x180
This can be reproduced by running the ftrace test case of kselftest, the
test case will hot-unplug the CPU and the CPU will attach to the NULL
sched-domain during scheduler teardown.
The step 2 for the rewrite select_idle_siblings():
| Step 2) tracks the average cost of the scan and compares this to the
| average idle time guestimate for the CPU doing the wakeup.
If the CPU which doing the wakeup is the going hot-unplug CPU, then NULL
sched domain will be dereferenced to acquire the average cost of the scan.
This patch fix it by failing the search of an idle CPU in the LLC process
if this sched domain is NULL.
Tested-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1475971443-3187-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull more vfs updates from Al Viro:
">rename2() work from Miklos + current_time() from Deepa"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Replace current_fs_time() with current_time()
fs: Replace CURRENT_TIME_SEC with current_time() for inode timestamps
fs: Replace CURRENT_TIME with current_time() for inode timestamps
fs: proc: Delete inode time initializations in proc_alloc_inode()
vfs: Add current_time() api
vfs: add note about i_op->rename changes to porting
fs: rename "rename2" i_op to "rename"
vfs: remove unused i_op->rename
fs: make remaining filesystems use .rename2
libfs: support RENAME_NOREPLACE in simple_rename()
fs: support RENAME_NOREPLACE for local filesystems
ncpfs: fix unused variable warning
The __latent_entropy gcc attribute can be used only on functions and
variables. If it is on a function then the plugin will instrument it for
gathering control-flow entropy. If the attribute is on a variable then
the plugin will initialize it with random contents. The variable must
be an integer, an integer array type or a structure with integer fields.
These specific functions have been selected because they are init
functions (to help gather boot-time entropy), are called at unpredictable
times, or they have variable loops, each of which provide some level of
latent entropy.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message]
Signed-off-by: Kees Cook <keescook@chromium.org>
This adds a new gcc plugin named "latent_entropy". It is designed to
extract as much possible uncertainty from a running system at boot time as
possible, hoping to capitalize on any possible variation in CPU operation
(due to runtime data differences, hardware differences, SMP ordering,
thermal timing variation, cache behavior, etc).
At the very least, this plugin is a much more comprehensive example for
how to manipulate kernel code using the gcc plugin internals.
The need for very-early boot entropy tends to be very architecture or
system design specific, so this plugin is more suited for those sorts
of special cases. The existing kernel RNG already attempts to extract
entropy from reliable runtime variation, but this plugin takes the idea to
a logical extreme by permuting a global variable based on any variation
in code execution (e.g. a different value (and permutation function)
is used to permute the global based on loop count, case statement,
if/then/else branching, etc).
To do this, the plugin starts by inserting a local variable in every
marked function. The plugin then adds logic so that the value of this
variable is modified by randomly chosen operations (add, xor and rol) and
random values (gcc generates separate static values for each location at
compile time and also injects the stack pointer at runtime). The resulting
value depends on the control flow path (e.g., loops and branches taken).
Before the function returns, the plugin mixes this local variable into
the latent_entropy global variable. The value of this global variable
is added to the kernel entropy pool in do_one_initcall() and _do_fork(),
though it does not credit any bytes of entropy to the pool; the contents
of the global are just used to mix the pool.
Additionally, the plugin can pre-initialize arrays with build-time
random contents, so that two different kernel builds running on identical
hardware will not have the same starting values.
Signed-off-by: Emese Revfy <re.emese@gmail.com>
[kees: expanded commit message and code comments]
Signed-off-by: Kees Cook <keescook@chromium.org>
Pull misc vfs updates from Al Viro:
"Assorted misc bits and pieces.
There are several single-topic branches left after this (rename2
series from Miklos, current_time series from Deepa Dinamani, xattr
series from Andreas, uaccess stuff from from me) and I'd prefer to
send those separately"
* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (39 commits)
proc: switch auxv to use of __mem_open()
hpfs: support FIEMAP
cifs: get rid of unused arguments of CIFSSMBWrite()
posix_acl: uapi header split
posix_acl: xattr representation cleanups
fs/aio.c: eliminate redundant loads in put_aio_ring_file
fs/internal.h: add const to ns_dentry_operations declaration
compat: remove compat_printk()
fs/buffer.c: make __getblk_slow() static
proc: unsigned file descriptors
fs/file: more unsigned file descriptors
fs: compat: remove redundant check of nr_segs
cachefiles: Fix attempt to read i_blocks after deleting file [ver #2]
cifs: don't use memcpy() to copy struct iov_iter
get rid of separate multipage fault-in primitives
fs: Avoid premature clearing of capabilities
fs: Give dentry to inode_change_ok() instead of inode
fuse: Propagate dentry down to inode_change_ok()
ceph: Propagate dentry down to inode_change_ok()
xfs: Propagate dentry down to inode_change_ok()
...
Pull protection keys syscall interface from Thomas Gleixner:
"This is the final step of Protection Keys support which adds the
syscalls so user space can actually allocate keys and protect memory
areas with them. Details and usage examples can be found in the
documentation.
The mm side of this has been acked by Mel"
* 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/pkeys: Update documentation
x86/mm/pkeys: Do not skip PKRU register if debug registers are not used
x86/pkeys: Fix pkeys build breakage for some non-x86 arches
x86/pkeys: Add self-tests
x86/pkeys: Allow configuration of init_pkru
x86/pkeys: Default to a restrictive init PKRU
pkeys: Add details of system call use to Documentation/
generic syscalls: Wire up memory protection keys syscalls
x86: Wire up protection keys system calls
x86/pkeys: Allocation/free syscalls
x86/pkeys: Make mprotect_key() mask off additional vm_flags
mm: Implement new pkey_mprotect() system call
x86/pkeys: Add fault handling for PF_PK page fault bit
Pull scheduler fix from Thomas Gleixner:
"A revert of a commit which pointelessly widened a preempt disabled
section which in turn caused might_sleep() to trigger.
The patch intended to prevent usage of smp_processor_id() in
preemptible context, but the usage in that case is fine because the
thread is pinned on a single cpu and therefore cannot be migrated off"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "sched/core: Do not use smp_processor_id() with preempt enabled in smpboot_thread_fn()"
Pull timer fix from Thomas Gleixner:
"A single fix for a regression introduced in 4.8 which causes the
trace/perf clock to return random nonsense if CONFIG_DEBUG_TIMEKEEPING
is set"
* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Fix __ktime_get_fast_ns() regression
Merge my system logging cleanups, triggered by the broken '\n' patches.
The line continuation handling has been broken basically forever, and
the code to handle the system log records was both confusing and
dubious. And it would do entirely the wrong thing unless you always had
a terminating newline, partly because it couldn't actually see whether a
message was marked KERN_CONT or not (but partly because the LOG_CONT
handling in the recording code was rather confusing too).
This re-introduces a real semantically meaningful KERN_CONT, and fixes
the few places I noticed where it was missing. There are probably more
missing cases, since KERN_CONT hasn't actually had any semantic meaning
for at least four years (other than the checkpatch meaning of "no log
level necessary, this is a continuation line").
This also allows the combination of KERN_CONT and a log level. In that
case the log level will be ignored if the merging with a previous line
is successful, but if a new record is needed, that new record will now
get the right log level.
That also means that you can at least in theory combine KERN_CONT with
the "pr_info()" style helpers, although any use of pr_fmt() prefixing
would make that just result in a mess, of course (the prefix would end
up in the middle of a continuing line).
* printk-cleanups:
printk: make reading the kernel log flush pending lines
printk: re-organize log_output() to be more legible
printk: split out core logging code into helper function
printk: reinstate KERN_CONT for printing continuation lines
That will mean that any possible subsequent continuation will now be
broken up onto a line of its own (since reading the log has finalized
the beginning og the line), but if user space has activated system
logging (or if there's a kernel message dump going on) that is the right
thing to do.
And now that we actually get the continuation flags _right_ for this
all, the user space logger that is reading the kernel messages can
actually see the continuation marker. Not that anybody seems to really
bother with it (or care), but in theory user space can do its own
message stitching.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Avoid some duplicate logic now that we can return early, and update the
comments for the new LOG_CONT world order.
This also stops the continuation flushing from just using random record
flags for the flushing action, instead taking the flags from the proper
original line and updating them as we add continuations to it.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The code that actually decides how to log the message (whether to put it
directly into the record log, whether to append it to an existing
buffered log, or whether to start a new buffered log) is fairly
non-obvious code in the middle of the vprintk_emit() function.
Splitting that code up into a helper function makes it easier to
understand, but perhaps more importantly also allows for the code to
just return early out of the helper function once it has made the
decision about where the new log content goes.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Long long ago the kernel log buffer was a buffered stream of bytes, very
much like stdio in user space. It supported log levels by scanning the
stream and noticing the log level markers at the beginning of each line,
but if you wanted to print a partial line in multiple chunks, you just
did multiple printk() calls, and it just automatically worked.
Except when it didn't, and you had very confusing output when different
lines got all mixed up with each other. Then you got fragment lines
mixing with each other, or with non-fragment lines, because it was
traditionally impossible to tell whether a printk() call was a
continuation or not.
To at least help clarify the issue of continuation lines, we added a
KERN_CONT marker back in 2007 to mark continuation lines:
4749252776 ("printk: add KERN_CONT annotation").
That continuation marker was initially an empty string, and didn't
actuall make any semantic difference. But it at least made it possible
to annotate the source code, and have check-patch notice that a printk()
didn't need or want a log level marker, because it was a continuation of
a previous line.
To avoid the ambiguity between a continuation line that had that
KERN_CONT marker, and a printk with no level information at all, we then
in 2009 made KERN_CONT be a real log level marker which meant that we
could now reliably tell the difference between the two cases.
5fd29d6ccb ("printk: clean up handling of log-levels and newlines")
and we could take advantage of that to make sure we didn't mix up
continuation lines with lines that just didn't have any loglevel at all.
Then, in 2012, the kernel log buffer was changed to be a "record" based
log, where each line was a record that has a loglevel and a timestamp.
You can see the beginning of that conversion in commits
e11fea92e1 ("kmsg: export printk records to the /dev/kmsg interface")
7ff9554bb5 ("printk: convert byte-buffer to variable-length record buffer")
with a number of follow-up commits to fix some painful fallout from that
conversion. Over all, it took a couple of months to sort out most of
it. But the upside was that you could have concurrent readers (and
writers) of the kernel log and not have lines with mixed output in them.
And one particular pain-point for the record-based kernel logging was
exactly the fragmentary lines that are generated in smaller chunks. In
order to still log them as one recrod, the continuation lines need to be
attached to the previous record properly.
However the explicit continuation record marker that is actually useful
for this exact case was actually removed in aroundm the same time by commit
61e99ab8e3 ("printk: remove the now unnecessary "C" annotation for KERN_CONT")
due to the incorrect belief that KERN_CONT wasn't meaningful. The
ambiguity between "is this a continuation line" or "is this a plain
printk with no log level information" was reintroduced, and in fact
became an even bigger pain point because there was now the whole
record-level merging of kernel messages going on.
This patch reinstates the KERN_CONT as a real non-empty string marker,
so that the ambiguity is fixed once again.
But it's not a plain revert of that original removal: in the four years
since we made KERN_CONT an empty string again, not only has the format
of the log level markers changed, we've also had some usage changes in
this area.
For example, some ACPI code seems to use KERN_CONT _together_ with a log
level, and now uses both the KERN_CONT marker and (for example) a
KERN_INFO marker to show that it's an informational continuation of a
line.
Which is actually not a bad idea - if the continuation line cannot be
attached to its predecessor, without the log level information we don't
know what log level to assign to it (and we traditionally just assigned
it the default loglevel). So having both a log level and the KERN_CONT
marker is not necessarily a bad idea, but it does mean that we need to
actually iterate over potentially multiple markers, rather than just a
single one.
Also, since KERN_CONT was still conceptually needed, and encouraged, but
didn't actually _do_ anything, we've also had the reverse problem:
rather than having too many annotations it has too few, and there is bit
rot with code that no longer marks the continuation lines with the
KERN_CONT marker.
So this patch not only re-instates the non-empty KERN_CONT marker, it
also fixes up the cases of bit-rot I noticed in my own logs.
There are probably other cases where KERN_CONT will be needed to be
added, either because it is new code that never dealt with the need for
KERN_CONT, or old code that has bitrotted without anybody noticing.
That said, we should strive to avoid the need for KERN_CONT. It does
result in real problems for logging, and should generally not be seen as
a good feature. If we some day can get rid of the feature entirely,
because nobody does any fragmented printk calls, that would be lovely.
But until that point, let's at mark the code that relies on the hacky
multi-fragment kernel printk's. Not only does it avoid the ambiguity,
it also annotates code as "maybe this would be good to fix some day".
(That said, particularly during single-threaded bootup, the downsides of
KERN_CONT are very limited. Things get much hairier when you have
multiple threads going on and user level reading and writing logs too).
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge updates from Andrew Morton:
- fsnotify updates
- ocfs2 updates
- all of MM
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (127 commits)
console: don't prefer first registered if DT specifies stdout-path
cred: simpler, 1D supplementary groups
CREDITS: update Pavel's information, add GPG key, remove snail mail address
mailmap: add Johan Hovold
.gitattributes: set git diff driver for C source code files
uprobes: remove function declarations from arch/{mips,s390}
spelling.txt: "modeled" is spelt correctly
nmi_backtrace: generate one-line reports for idle cpus
arch/tile: adopt the new nmi_backtrace framework
nmi_backtrace: do a local dump_stack() instead of a self-NMI
nmi_backtrace: add more trigger_*_cpu_backtrace() methods
min/max: remove sparse warnings when they're nested
Documentation/filesystems/proc.txt: add more description for maps/smaps
mm, proc: fix region lost in /proc/self/smaps
proc: fix timerslack_ns CAP_SYS_NICE check when adjusting self
proc: add LSM hook checks to /proc/<tid>/timerslack_ns
proc: relax /proc/<tid>/timerslack_ns capability requirements
meminfo: break apart a very long seq_printf with #ifdefs
seq/proc: modify seq_put_decimal_[u]ll to take a const char *, not char
proc: faster /proc/*/status
...
If a device tree specifies a preferred device for kernel console output
via the stdout-path or linux,stdout-path chosen node properties or the
stdout alias then the kernel ought to honor it & output the kernel
console to that device. As it stands, this isn't the case. Whilst we
parse the stdout-path properties & set an of_stdout variable from
of_alias_scan(), and use that from of_console_check() to determine
whether to add a console device as a preferred console whilst
registering it, we also prefer the first registered console if no other
has been selected at the time of its registration.
This means that if a console other than the one the device tree selects
via stdout-path is registered first, we will switch to using it & when
the stdout-path console is later registered the call to
add_preferred_console() via of_console_check() is too late to do
anything useful. In practice this seems to mean that we switch to the
dummy console device fairly early & see no further console output:
Console: colour dummy device 80x25
console [tty0] enabled
bootconsole [ns16550a0] disabled
Fix this by not automatically preferring the first registered console if
one is specified by the device tree. This allows consoles to be
registered but not enabled, and once the driver for the console selected
by stdout-path calls of_console_check() the driver will be added to the
list of preferred consoles before any other console has been enabled.
When that console is then registered via register_console() it will be
enabled as expected.
Link: http://lkml.kernel.org/r/20160809151937.26118-1-paul.burton@imgtec.com
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ivan Delalande <colona@arista.com>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Jan Kara <jack@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Perches <joe@perches.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Frank Rowand <frowand.list@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current supplementary groups code can massively overallocate memory and
is implemented in a way so that access to individual gid is done via 2D
array.
If number of gids is <= 32, memory allocation is more or less tolerable
(140/148 bytes). But if it is not, code allocates full page (!)
regardless and, what's even more fun, doesn't reuse small 32-entry
array.
2D array means dependent shifts, loads and LEAs without possibility to
optimize them (gid is never known at compile time).
All of the above is unnecessary. Switch to the usual
trailing-zero-len-array scheme. Memory is allocated with
kmalloc/vmalloc() and only as much as needed. Accesses become simpler
(LEA 8(gi,idx,4) or even without displacement).
Maximum number of gids is 65536 which translates to 256KB+8 bytes. I
think kernel can handle such allocation.
On my usual desktop system with whole 9 (nine) aux groups, struct
group_info shrinks from 148 bytes to 44 bytes, yay!
Nice side effects:
- "gi->gid[i]" is shorter than "GROUP_AT(gi, i)", less typing,
- fix little mess in net/ipv4/ping.c
should have been using GROUP_AT macro but this point becomes moot,
- aux group allocation is persistent and should be accounted as such.
Link: http://lkml.kernel.org/r/20160817201927.GA2096@p183.telecom.by
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Vasily Kulikov <segoon@openwall.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When doing an nmi backtrace of many cores, most of which are idle, the
output is a little overwhelming and very uninformative. Suppress
messages for cpus that are idling when they are interrupted and just
emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN".
We do this by grouping all the cpuidle code together into a new
.cpuidle.text section, and then checking the address of the interrupted
PC to see if it lies within that section.
This commit suitably tags x86 and tile idle routines, and only adds in
the minimal framework for other architectures.
Link: http://lkml.kernel.org/r/1472487169-14923-5-git-send-email-cmetcalf@mellanox.com
Signed-off-by: Chris Metcalf <cmetcalf@mellanox.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Daniel Thompson <daniel.thompson@linaro.org> [arm]
Tested-by: Petr Mladek <pmladek@suse.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The global zero page is used to satisfy an anonymous read fault. If
THP(Transparent HugePage) is enabled then the global huge zero page is
used. The global huge zero page uses an atomic counter for reference
counting and is allocated/freed dynamically according to its counter
value.
CPU time spent on that counter will greatly increase if there are a lot
of processes doing anonymous read faults. This patch proposes a way to
reduce the access to the global counter so that the CPU load can be
reduced accordingly.
To do this, a new flag of the mm_struct is introduced:
MMF_USED_HUGE_ZERO_PAGE. With this flag, the process only need to touch
the global counter in two cases:
1 The first time it uses the global huge zero page;
2 The time when mm_user of its mm_struct reaches zero.
Note that right now, the huge zero page is eligible to be freed as soon
as its last use goes away. With this patch, the page will not be
eligible to be freed until the exit of the last process from which it
was ever used.
And with the use of mm_user, the kthread is not eligible to use huge
zero page either. Since no kthread is using huge zero page today, there
is no difference after applying this patch. But if that is not desired,
I can change it to when mm_count reaches zero.
Case used for test on Haswell EP:
usemem -n 72 --readonly -j 0x200000 100G
Which spawns 72 processes and each will mmap 100G anonymous space and
then do read only access to that space sequentially with a step of 2MB.
CPU cycles from perf report for base commit:
54.03% usemem [kernel.kallsyms] [k] get_huge_zero_page
CPU cycles from perf report for this commit:
0.11% usemem [kernel.kallsyms] [k] mm_get_huge_zero_page
Performance(throughput) of the workload for base commit: 1784430792
Performance(throughput) of the workload for this commit: 4726928591
164% increase.
Runtime of the workload for base commit: 707592 us
Runtime of the workload for this commit: 303970 us
50% drop.
Link: http://lkml.kernel.org/r/fe51a88f-446a-4622-1363-ad1282d71385@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are no users of exit_oom_victim on !current task anymore so enforce
the API to always work on the current.
Link: http://lkml.kernel.org/r/1472119394-11342-8-git-send-email-mhocko@kernel.org
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 7407054209 ("oom, suspend: fix oom_reaper vs.
oom_killer_disable race") has workaround an existing race between
oom_killer_disable and oom_reaper by adding another round of
try_to_freeze_tasks after the oom killer was disabled. This was the
easiest thing to do for a late 4.7 fix. Let's fix it properly now.
After "oom: keep mm of the killed task available" we no longer have to
call exit_oom_victim from the oom reaper because we have stable mm
available and hide the oom_reaped mm by MMF_OOM_SKIP flag. So let's
remove exit_oom_victim and the race described in the above commit
doesn't exist anymore if.
Unfortunately this alone is not sufficient for the oom_killer_disable
usecase because now we do not have any reliable way to reach
exit_oom_victim (the victim might get stuck on a way to exit for an
unbounded amount of time). OOM killer can cope with that by checking mm
flags and move on to another victim but we cannot do the same for
oom_killer_disable as we would lose the guarantee of no further
interference of the victim with the rest of the system. What we can do
instead is to cap the maximum time the oom_killer_disable waits for
victims. The only current user of this function (pm suspend) already
has a concept of timeout for back off so we can reuse the same value
there.
Let's drop set_freezable for the oom_reaper kthread because it is no
longer needed as the reaper doesn't wake or thaw any processes.
Link: http://lkml.kernel.org/r/1472119394-11342-7-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After "oom: keep mm of the killed task available" we can safely detect
an oom victim by checking task->signal->oom_mm so we do not need the
signal_struct counter anymore so let's get rid of it.
This alone wouldn't be sufficient for nommu archs because
exit_oom_victim doesn't hide the process from the oom killer anymore.
We can, however, mark the mm with a MMF flag in __mmput. We can reuse
MMF_OOM_REAPED and rename it to a more generic MMF_OOM_SKIP.
Link: http://lkml.kernel.org/r/1472119394-11342-6-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Lockdep complains that __mmdrop is not safe from the softirq context:
=================================
[ INFO: inconsistent lock state ]
4.6.0-oomfortification2-00011-geeb3eadeab96-dirty #949 Tainted: G W
---------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
swapper/1/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
(pgd_lock){+.?...}, at: pgd_free+0x19/0x6b
{SOFTIRQ-ON-W} state was registered at:
__lock_acquire+0xa06/0x196e
lock_acquire+0x139/0x1e1
_raw_spin_lock+0x32/0x41
__change_page_attr_set_clr+0x2a5/0xacd
change_page_attr_set_clr+0x16f/0x32c
set_memory_nx+0x37/0x3a
free_init_pages+0x9e/0xc7
alternative_instructions+0xa2/0xb3
check_bugs+0xe/0x2d
start_kernel+0x3ce/0x3ea
x86_64_start_reservations+0x2a/0x2c
x86_64_start_kernel+0x17a/0x18d
irq event stamp: 105916
hardirqs last enabled at (105916): free_hot_cold_page+0x37e/0x390
hardirqs last disabled at (105915): free_hot_cold_page+0x2c1/0x390
softirqs last enabled at (105878): _local_bh_enable+0x42/0x44
softirqs last disabled at (105879): irq_exit+0x6f/0xd1
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(pgd_lock);
<Interrupt>
lock(pgd_lock);
*** DEADLOCK ***
1 lock held by swapper/1/0:
#0: (rcu_callback){......}, at: rcu_process_callbacks+0x390/0x800
stack backtrace:
CPU: 1 PID: 0 Comm: swapper/1 Tainted: G W 4.6.0-oomfortification2-00011-geeb3eadeab96-dirty #949
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014
Call Trace:
<IRQ>
print_usage_bug.part.25+0x259/0x268
mark_lock+0x381/0x567
__lock_acquire+0x993/0x196e
lock_acquire+0x139/0x1e1
_raw_spin_lock+0x32/0x41
pgd_free+0x19/0x6b
__mmdrop+0x25/0xb9
__put_task_struct+0x103/0x11e
delayed_put_task_struct+0x157/0x15e
rcu_process_callbacks+0x660/0x800
__do_softirq+0x1ec/0x4d5
irq_exit+0x6f/0xd1
smp_apic_timer_interrupt+0x42/0x4d
apic_timer_interrupt+0x8e/0xa0
<EOI>
arch_cpu_idle+0xf/0x11
default_idle_call+0x32/0x34
cpu_startup_entry+0x20c/0x399
start_secondary+0xfe/0x101
More over commit a79e53d856 ("x86/mm: Fix pgd_lock deadlock") was
explicit about pgd_lock not to be called from the irq context. This
means that __mmdrop called from free_signal_struct has to be postponed
to a user context. We already have a similar mechanism for mmput_async
so we can use it here as well. This is safe because mm_count is pinned
by mm_users.
This fixes bug introduced by "oom: keep mm of the killed task available"
Link: http://lkml.kernel.org/r/1472119394-11342-5-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
oom_reap_task has to call exit_oom_victim in order to make sure that the
oom vicim will not block the oom killer for ever. This is, however,
opening new problems (e.g oom_killer_disable exclusion - see commit
7407054209 ("oom, suspend: fix oom_reaper vs. oom_killer_disable
race")). exit_oom_victim should be only called from the victim's
context ideally.
One way to achieve this would be to rely on per mm_struct flags. We
already have MMF_OOM_REAPED to hide a task from the oom killer since
"mm, oom: hide mm which is shared with kthread or global init". The
problem is that the exit path:
do_exit
exit_mm
tsk->mm = NULL;
mmput
__mmput
exit_oom_victim
doesn't guarantee that exit_oom_victim will get called in a bounded
amount of time. At least exit_aio depends on IO which might get blocked
due to lack of memory and who knows what else is lurking there.
This patch takes a different approach. We remember tsk->mm into the
signal_struct and bind it to the signal struct life time for all oom
victims. __oom_reap_task_mm as well as oom_scan_process_thread do not
have to rely on find_lock_task_mm anymore and they will have a reliable
reference to the mm struct. As a result all the oom specific
communication inside the OOM killer can be done via tsk->signal->oom_mm.
Increasing the signal_struct for something as unlikely as the oom killer
is far from ideal but this approach will make the code much more
reasonable and long term we even might want to move task->mm into the
signal_struct anyway. In the next step we might want to make the oom
killer exclusion and access to memory reserves completely independent
which would be also nice.
Link: http://lkml.kernel.org/r/1472119394-11342-4-git-send-email-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull VFS splice updates from Al Viro:
"There's a bunch of branches this cycle, both mine and from other folks
and I'd rather send pull requests separately.
This one is the conversion of ->splice_read() to ITER_PIPE iov_iter
(and introduction of such). Gets rid of a lot of code in fs/splice.c
and elsewhere; there will be followups, but these are for the next
cycle... Some pipe/splice-related cleanups from Miklos in the same
branch as well"
* 'work.splice_read' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
pipe: fix comment in pipe_buf_operations
pipe: add pipe_buf_steal() helper
pipe: add pipe_buf_confirm() helper
pipe: add pipe_buf_release() helper
pipe: add pipe_buf_get() helper
relay: simplify relay_file_read()
switch default_file_splice_read() to use of pipe-backed iov_iter
switch generic_file_splice_read() to use of ->read_iter()
new iov_iter flavour: pipe-backed
fuse_dev_splice_read(): switch to add_to_pipe()
skb_splice_bits(): get rid of callback
new helper: add_to_pipe()
splice: lift pipe_lock out of splice_to_pipe()
splice: switch get_iovec_page_array() to iov_iter
splice_to_pipe(): don't open-code wakeup_pipe_readers()
consistent treatment of EFAULT on O_DIRECT read/write
Pull block layer updates from Jens Axboe:
"This is the main pull request for block layer changes in 4.9.
As mentioned at the last merge window, I've changed things up and now
do just one branch for core block layer changes, and driver changes.
This avoids dependencies between the two branches. Outside of this
main pull request, there are two topical branches coming as well.
This pull request contains:
- A set of fixes, and a conversion to blk-mq, of nbd. From Josef.
- Set of fixes and updates for lightnvm from Matias, Simon, and Arnd.
Followup dependency fix from Geert.
- General fixes from Bart, Baoyou, Guoqing, and Linus W.
- CFQ async write starvation fix from Glauber.
- Add supprot for delayed kick of the requeue list, from Mike.
- Pull out the scalable bitmap code from blk-mq-tag.c and make it
generally available under the name of sbitmap. Only blk-mq-tag uses
it for now, but the blk-mq scheduling bits will use it as well.
From Omar.
- bdev thaw error progagation from Pierre.
- Improve the blk polling statistics, and allow the user to clear
them. From Stephen.
- Set of minor cleanups from Christoph in block/blk-mq.
- Set of cleanups and optimizations from me for block/blk-mq.
- Various nvme/nvmet/nvmeof fixes from the various folks"
* 'for-4.9/block' of git://git.kernel.dk/linux-block: (54 commits)
fs/block_dev.c: return the right error in thaw_bdev()
nvme: Pass pointers, not dma addresses, to nvme_get/set_features()
nvme/scsi: Remove power management support
nvmet: Make dsm number of ranges zero based
nvmet: Use direct IO for writes
admin-cmd: Added smart-log command support.
nvme-fabrics: Add host_traddr options field to host infrastructure
nvme-fabrics: revise host transport option descriptions
nvme-fabrics: rework nvmf_get_address() for variable options
nbd: use BLK_MQ_F_BLOCKING
blkcg: Annotate blkg_hint correctly
cfq: fix starvation of asynchronous writes
blk-mq: add flag for drivers wanting blocking ->queue_rq()
blk-mq: remove non-blocking pass in blk_mq_map_request
blk-mq: get rid of manual run of queue with __blk_mq_run_hw_queue()
block: export bio_free_pages to other modules
lightnvm: propagate device_add() error code
lightnvm: expose device geometry through sysfs
lightnvm: control life of nvm_dev in driver
blk-mq: register device instead of disk
...
Pull livepatching updates from Jiri Kosina:
- fix for patching modules that contain .altinstructions or
.parainstructions sections, from Jessica Yu
- make TAINT_LIVEPATCH a per-module flag (so that it's immediately
clear which module caused the taint), from Josh Poimboeuf
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/livepatching:
livepatch/module: make TAINT_LIVEPATCH module-specific
Documentation: livepatch: add section about arch-specific code
livepatch/x86: apply alternatives and paravirt patches after relocations
livepatch: use arch_klp_init_object_loaded() to finish arch-specific tasks
The big change is the addition of the hwlat tracer. It not only detects
SMIs, but also other latency that's caused by the hardware. I have detected
some latency from large boxes having bus contention.
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Merge tag 'trace-v4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
"This release cycle is rather small. Just a few fixes to tracing.
The big change is the addition of the hwlat tracer. It not only
detects SMIs, but also other latency that's caused by the hardware. I
have detected some latency from large boxes having bus contention"
* tag 'trace-v4.9' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Call traceoff trigger after event is recorded
ftrace/scripts: Add helper script to bisect function tracing problem functions
tracing: Have max_latency be defined for HWLAT_TRACER as well
tracing: Add NMI tracing in hwlat detector
tracing: Have hwlat trace migrate across tracing_cpumask CPUs
tracing: Add documentation for hwlat_detector tracer
tracing: Added hardware latency tracer
ftrace: Access ret_stack->subtime only in the function profiler
function_graph: Handle TRACE_BPUTS in print_graph_comment
tracing/uprobe: Drop isdigit() check in create_trace_uprobe
All architectures:
Move `make kvmconfig` stubs from x86; use 64 bits for debugfs stats.
ARM:
Important fixes for not using an in-kernel irqchip; handle SError
exceptions and present them to guests if appropriate; proxying of GICV
access at EL2 if guest mappings are unsafe; GICv3 on AArch32 on ARMv8;
preparations for GICv3 save/restore, including ABI docs; cleanups and
a bit of optimizations.
MIPS:
A couple of fixes in preparation for supporting MIPS EVA host kernels;
MIPS SMP host & TLB invalidation fixes.
PPC:
Fix the bug which caused guests to falsely report lockups; other minor
fixes; a small optimization.
s390:
Lazy enablement of runtime instrumentation; up to 255 CPUs for nested
guests; rework of machine check deliver; cleanups and fixes.
x86:
IOMMU part of AMD's AVIC for vmexit-less interrupt delivery; Hyper-V
TSC page; per-vcpu tsc_offset in debugfs; accelerated INS/OUTS in
nVMX; cleanups and fixes.
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Merge tag 'kvm-4.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Radim Krčmář:
"All architectures:
- move `make kvmconfig` stubs from x86
- use 64 bits for debugfs stats
ARM:
- Important fixes for not using an in-kernel irqchip
- handle SError exceptions and present them to guests if appropriate
- proxying of GICV access at EL2 if guest mappings are unsafe
- GICv3 on AArch32 on ARMv8
- preparations for GICv3 save/restore, including ABI docs
- cleanups and a bit of optimizations
MIPS:
- A couple of fixes in preparation for supporting MIPS EVA host
kernels
- MIPS SMP host & TLB invalidation fixes
PPC:
- Fix the bug which caused guests to falsely report lockups
- other minor fixes
- a small optimization
s390:
- Lazy enablement of runtime instrumentation
- up to 255 CPUs for nested guests
- rework of machine check deliver
- cleanups and fixes
x86:
- IOMMU part of AMD's AVIC for vmexit-less interrupt delivery
- Hyper-V TSC page
- per-vcpu tsc_offset in debugfs
- accelerated INS/OUTS in nVMX
- cleanups and fixes"
* tag 'kvm-4.9-1' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (140 commits)
KVM: MIPS: Drop dubious EntryHi optimisation
KVM: MIPS: Invalidate TLB by regenerating ASIDs
KVM: MIPS: Split kernel/user ASID regeneration
KVM: MIPS: Drop other CPU ASIDs on guest MMU changes
KVM: arm/arm64: vgic: Don't flush/sync without a working vgic
KVM: arm64: Require in-kernel irqchip for PMU support
KVM: PPC: Book3s PR: Allow access to unprivileged MMCR2 register
KVM: PPC: Book3S PR: Support 64kB page size on POWER8E and POWER8NVL
KVM: PPC: Book3S: Remove duplicate setting of the B field in tlbie
KVM: PPC: BookE: Fix a sanity check
KVM: PPC: Book3S HV: Take out virtual core piggybacking code
KVM: PPC: Book3S: Treat VTB as a per-subcore register, not per-thread
ARM: gic-v3: Work around definition of gic_write_bpr1
KVM: nVMX: Fix the NMI IDT-vectoring handling
KVM: VMX: Enable MSR-BASED TPR shadow even if APICv is inactive
KVM: nVMX: Fix reload apic access page warning
kvmconfig: add virtio-gpu to config fragment
config: move x86 kvm_guest.config to a common location
arm64: KVM: Remove duplicating init code for setting VMID
ARM: KVM: Support vgic-v3
...
Pull namespace updates from Eric Biederman:
"This set of changes is a number of smaller things that have been
overlooked in other development cycles focused on more fundamental
change. The devpts changes are small things that were a distraction
until we managed to kill off DEVPTS_MULTPLE_INSTANCES. There is an
trivial regression fix to autofs for the unprivileged mount changes
that went in last cycle. A pair of ioctls has been added by Andrey
Vagin making it is possible to discover the relationships between
namespaces when referring to them through file descriptors.
The big user visible change is starting to add simple resource limits
to catch programs that misbehave. With namespaces in general and user
namespaces in particular allowing users to use more kinds of
resources, it has become important to have something to limit errant
programs. Because the purpose of these limits is to catch errant
programs the code needs to be inexpensive to use as it always on, and
the default limits need to be high enough that well behaved programs
on well behaved systems don't encounter them.
To this end, after some review I have implemented per user per user
namespace limits, and use them to limit the number of namespaces. The
limits being per user mean that one user can not exhause the limits of
another user. The limits being per user namespace allow contexts where
the limit is 0 and security conscious folks can remove from their
threat anlysis the code used to manage namespaces (as they have
historically done as it root only). At the same time the limits being
per user namespace allow other parts of the system to use namespaces.
Namespaces are increasingly being used in application sand boxing
scenarios so an all or nothing disable for the entire system for the
security conscious folks makes increasing use of these sandboxes
impossible.
There is also added a limit on the maximum number of mounts present in
a single mount namespace. It is nontrivial to guess what a reasonable
system wide limit on the number of mount structure in the kernel would
be, especially as it various based on how a system is using
containers. A limit on the number of mounts in a mount namespace
however is much easier to understand and set. In most cases in
practice only about 1000 mounts are used. Given that some autofs
scenarious have the potential to be 30,000 to 50,000 mounts I have set
the default limit for the number of mounts at 100,000 which is well
above every known set of users but low enough that the mount hash
tables don't degrade unreaonsably.
These limits are a start. I expect this estabilishes a pattern that
other limits for resources that namespaces use will follow. There has
been interest in making inotify event limits per user per user
namespace as well as interest expressed in making details about what
is going on in the kernel more visible"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (28 commits)
autofs: Fix automounts by using current_real_cred()->uid
mnt: Add a per mount namespace limit on the number of mounts
netns: move {inc,dec}_net_namespaces into #ifdef
nsfs: Simplify __ns_get_path
tools/testing: add a test to check nsfs ioctl-s
nsfs: add ioctl to get a parent namespace
nsfs: add ioctl to get an owning user namespace for ns file descriptor
kernel: add a helper to get an owning user namespace for a namespace
devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts
devpts: Remove sync_filesystems
devpts: Make devpts_kill_sb safe if fsi is NULL
devpts: Simplify devpts_mount by using mount_nodev
devpts: Move the creation of /dev/pts/ptmx into fill_super
devpts: Move parse_mount_options into fill_super
userns: When the per user per user namespace limit is reached return ENOSPC
userns; Document per user per user namespace limits.
mntns: Add a limit on the number of mount namespaces.
netns: Add a limit on the number of net namespaces
cgroupns: Add a limit on the number of cgroup namespaces
ipcns: Add a limit on the number of ipc namespaces
...
Pull networking updates from David Miller:
1) BBR TCP congestion control, from Neal Cardwell, Yuchung Cheng and
co. at Google. https://lwn.net/Articles/701165/
2) Do TCP Small Queues for retransmits, from Eric Dumazet.
3) Support collect_md mode for all IPV4 and IPV6 tunnels, from Alexei
Starovoitov.
4) Allow cls_flower to classify packets in ip tunnels, from Amir Vadai.
5) Support DSA tagging in older mv88e6xxx switches, from Andrew Lunn.
6) Support GMAC protocol in iwlwifi mwm, from Ayala Beker.
7) Support ndo_poll_controller in mlx5, from Calvin Owens.
8) Move VRF processing to an output hook and allow l3mdev to be
loopback, from David Ahern.
9) Support SOCK_DESTROY for UDP sockets. Also from David Ahern.
10) Congestion control in RXRPC, from David Howells.
11) Support geneve RX offload in ixgbe, from Emil Tantilov.
12) When hitting pressure for new incoming TCP data SKBs, perform a
partial rathern than a full purge of the OFO queue (which could be
huge). From Eric Dumazet.
13) Convert XFRM state and policy lookups to RCU, from Florian Westphal.
14) Support RX network flow classification to igb, from Gangfeng Huang.
15) Hardware offloading of eBPF in nfp driver, from Jakub Kicinski.
16) New skbmod packet action, from Jamal Hadi Salim.
17) Remove some inefficiencies in snmp proc output, from Jia He.
18) Add FIB notifications to properly propagate route changes to
hardware which is doing forwarding offloading. From Jiri Pirko.
19) New dsa driver for qca8xxx chips, from John Crispin.
20) Implement RFC7559 ipv6 router solicitation backoff, from Maciej
Żenczykowski.
21) Add L3 mode to ipvlan, from Mahesh Bandewar.
22) Support 802.1ad in mlx4, from Moshe Shemesh.
23) Support hardware LRO in mediatek driver, from Nelson Chang.
24) Add TC offloading to mlx5, from Or Gerlitz.
25) Convert various drivers to ethtool ksettings interfaces, from
Philippe Reynes.
26) TX max rate limiting for cxgb4, from Rahul Lakkireddy.
27) NAPI support for ath10k, from Rajkumar Manoharan.
28) Support XDP in mlx5, from Rana Shahout and Saeed Mahameed.
29) UDP replicast support in TIPC, from Richard Alpe.
30) Per-queue statistics for qed driver, from Sudarsana Reddy Kalluru.
31) Support BQL in thunderx driver, from Sunil Goutham.
32) TSO support in alx driver, from Tobias Regnery.
33) Add stream parser engine and use it in kcm.
34) Support async DHCP replies in ipconfig module, from Uwe
Kleine-König.
35) DSA port fast aging for mv88e6xxx driver, from Vivien Didelot.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1715 commits)
mlxsw: switchx2: Fix misuse of hard_header_len
mlxsw: spectrum: Fix misuse of hard_header_len
net/faraday: Stop NCSI device on shutdown
net/ncsi: Introduce ncsi_stop_dev()
net/ncsi: Rework the channel monitoring
net/ncsi: Allow to extend NCSI request properties
net/ncsi: Rework request index allocation
net/ncsi: Don't probe on the reserved channel ID (0x1f)
net/ncsi: Introduce NCSI_RESERVED_CHANNEL
net/ncsi: Avoid unused-value build warning from ia64-linux-gcc
net: Add netdev all_adj_list refcnt propagation to fix panic
net: phy: Add Edge-rate driver for Microsemi PHYs.
vmxnet3: Wake queue from reset work
i40e: avoid NULL pointer dereference and recursive errors on early PCI error
qed: Add RoCE ll2 & GSI support
qed: Add support for memory registeration verbs
qed: Add support for QP verbs
qed: PD,PKEY and CQ verb support
qed: Add support for RoCE hw init
qede: Add qedr framework
...
Pull audit updates from Paul Moore:
"Another relatively small pull request for v4.9 with just two patches.
The patch from Richard updates the list of features we support and
report back to userspace; this should have been sent earlier with the
rest of the v4.8 patches but it got lost in my inbox.
The second patch fixes a problem reported by our Android friends where
we weren't very consistent in recording PIDs"
* 'stable-4.9' of git://git.infradead.org/users/pcmoore/audit:
audit: add exclude filter extension to feature bitmap
audit: consistently record PIDs with task_tgid_nr()
This reverts commit 4fa5cd5245.
The original change widens a preempt-off section, to avoid a seemingly unsafe
smp_processor_id() use.
During review I overlooked two facts:
- The code to calls a non-trivial function callback:
ht->park(td->cpu);
... which might (and does occasionally) sleep, triggering the warning.
- More importantly, as pointed out by Peter Zijlstra, using
smp_processor_id() in that context is safe, if it's done from
a kernel thread that is pinned to a single CPU - which is the
case here.
So revert to the original code that enables preemption sooner.
Reported-by: kernel test robot <xiaolong.ye@intel.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Con Kolivas <kernel@kolivas.org>
Cc: Alfred Chen <cchalpha@gmail.com>
Link: http://lkml.kernel.org/r/20160930015102.GB20189@yexl-desktop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull CPU hotplug updates from Thomas Gleixner:
"Yet another batch of cpu hotplug core updates and conversions:
- Provide core infrastructure for multi instance drivers so the
drivers do not have to keep custom lists.
- Convert custom lists to the new infrastructure. The block-mq custom
list conversion comes through the block tree and makes the diffstat
tip over to more lines removed than added.
- Handle unbalanced hotplug enable/disable calls more gracefully.
- Remove the obsolete CPU_STARTING/DYING notifier support.
- Convert another batch of notifier users.
The relayfs changes which conflicted with the conversion have been
shipped to me by Andrew.
The remaining lot is targeted for 4.10 so that we finally can remove
the rest of the notifiers"
* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (46 commits)
cpufreq: Fix up conversion to hotplug state machine
blk/mq: Reserve hotplug states for block multiqueue
x86/apic/uv: Convert to hotplug state machine
s390/mm/pfault: Convert to hotplug state machine
mips/loongson/smp: Convert to hotplug state machine
mips/octeon/smp: Convert to hotplug state machine
fault-injection/cpu: Convert to hotplug state machine
padata: Convert to hotplug state machine
cpufreq: Convert to hotplug state machine
ACPI/processor: Convert to hotplug state machine
virtio scsi: Convert to hotplug state machine
oprofile/timer: Convert to hotplug state machine
block/softirq: Convert to hotplug state machine
lib/irq_poll: Convert to hotplug state machine
x86/microcode: Convert to hotplug state machine
sh/SH-X3 SMP: Convert to hotplug state machine
ia64/mca: Convert to hotplug state machine
ARM/OMAP/wakeupgen: Convert to hotplug state machine
ARM/shmobile: Convert to hotplug state machine
arm64/FP/SIMD: Convert to hotplug state machine
...
Pull irq updates from Thomas Gleixner:
"The irq departement proudly presents:
- A rework of the core infrastructure to optimally spread interrupt
for multiqueue devices. The first version was a bit naive and
failed to take thread siblings and other details into account.
Developed in cooperation with Christoph and Keith.
- Proper delegation of softirqs to ksoftirqd, so if ksoftirqd is
active then no further softirq processsing on interrupt return
happens. Otherwise we try to delegate and still run another batch
of network packets in the irq return path, which then tries to
delegate to ksoftirqd .....
- A proper machine parseable sysfs based alternative for
/proc/interrupts.
- ACPI support for the GICV3-ITS and ARM interrupt remapping
- Two new irq chips from the ARM SoC zoo: STM32-EXTI and MVEBU-PIC
- A new irq chip for the JCore (SuperH)
- The usual pile of small fixlets in core and irqchip drivers"
* 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
softirq: Let ksoftirqd do its job
genirq: Make function __irq_do_set_handler() static
ARM/dts: Add EXTI controller node to stm32f429
ARM/STM32: Select external interrupts controller
drivers/irqchip: Add STM32 external interrupts support
Documentation/dt-bindings: Document STM32 EXTI controller bindings
irqchip/mips-gic: Use for_each_set_bit to iterate over local IRQs
pci/msi: Retrieve affinity for a vector
genirq/affinity: Remove old irq spread infrastructure
genirq/msi: Switch to new irq spreading infrastructure
genirq/affinity: Provide smarter irq spreading infrastructure
genirq/msi: Add cpumask allocation to alloc_msi_entry
genirq: Expose interrupt information through sysfs
irqchip/gicv3-its: Use MADT ITS subtable to do PCI/MSI domain initialization
irqchip/gicv3-its: Factor out PCI-MSI part that might be reused for ACPI
irqchip/gicv3-its: Probe ITS in the ACPI way
irqchip/gicv3-its: Refactor ITS DT init code to prepare for ACPI
irqchip/gicv3-its: Cleanup for ITS domain initialization
PCI/MSI: Setup MSI domain on a per-device basis using IORT ACPI table
ACPI: Add new IORT functions to support MSI domain handling
...
Pull timer updates from Thomas Gleixner:
"A rather smalish set of updates for timers and timekeeping:
- Two core fixes to prevent potential undefinded behaviour about
which gcc is complaining rightfully.
- A fix to prevent stopping the tick on an (soon) offline CPU so it
can complete the shutdown procedure.
- Wait for clocks to stabilize before making decisions, so a not yet
validated clock is not rejected.
- The usual pile of fixes to the various clocksource drivers.
- Core code typo and include fixlets"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Include the correct header for errno definitions
clocksource/drivers/ti-32k: Prevent ftrace recursion
clocksource/mips-gic-timer: Stop checking cpu_has_counter
clocksource/mips-gic-timer: Print an error if IRQ setup fails
tick/nohz: Prevent stopping the tick on an offline CPU
clocksource/drivers/oxnas: Add OX820 compatible
clocksource/drivers/timer-atmel-pit: Simplify IRQ handler
clocksource/drivers/timer-atmel-pit: Remove uselesss WARN_ON_ONCE
clocksource/drivers/timer-atmel-pit: Drop at91sam926x_pit_common_init
clocksource/drivers/moxart: Replace panic by pr_err
clocksource/drivers/moxart: Replace setup_irq by request_irq
clocksource/drivers/moxart: Add Aspeed support
clocksource/drivers/moxart: Use struct to hold state
clocksource/drivers/moxart: Refactor enable/disable
time: Avoid undefined behaviour in ktime_add_safe()
time: Avoid undefined behaviour in timespec64_add_safe()
timekeeping: Prints the amounts of time spent during suspend
clocksource: Defer override invalidation unless clock is unstable
hrtimer: Spelling fixes
Pull x86 vdso updates from Ingo Molnar:
"The main changes in this cycle centered around adding support for
32-bit compatible C/R of the vDSO on 64-bit kernels, by Dmitry
Safonov"
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Use CONFIG_X86_X32_ABI to enable vdso prctl
x86/vdso: Only define map_vdso_randomized() if CONFIG_X86_64
x86/vdso: Only define prctl_map_vdso() if CONFIG_CHECKPOINT_RESTORE
x86/signal: Add SA_{X32,IA32}_ABI sa_flags
x86/ptrace: Down with test_thread_flag(TIF_IA32)
x86/coredump: Use pr_reg size, rather that TIF_IA32 flag
x86/arch_prctl/vdso: Add ARCH_MAP_VDSO_*
x86/vdso: Replace calculate_addr in map_vdso() with addr
x86/vdso: Unmap vdso blob on vvar mapping failure
Pull low-level x86 updates from Ingo Molnar:
"In this cycle this topic tree has become one of those 'super topics'
that accumulated a lot of changes:
- Add CONFIG_VMAP_STACK=y support to the core kernel and enable it on
x86 - preceded by an array of changes. v4.8 saw preparatory changes
in this area already - this is the rest of the work. Includes the
thread stack caching performance optimization. (Andy Lutomirski)
- switch_to() cleanups and all around enhancements. (Brian Gerst)
- A large number of dumpstack infrastructure enhancements and an
unwinder abstraction. The secret long term plan is safe(r) live
patching plus maybe another attempt at debuginfo based unwinding -
but all these current bits are standalone enhancements in a frame
pointer based debug environment as well. (Josh Poimboeuf)
- More __ro_after_init and const annotations. (Kees Cook)
- Enable KASLR for the vmemmap memory region. (Thomas Garnier)"
[ The virtually mapped stack changes are pretty fundamental, and not
x86-specific per se, even if they are only used on x86 right now. ]
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
x86/asm: Get rid of __read_cr4_safe()
thread_info: Use unsigned long for flags
x86/alternatives: Add stack frame dependency to alternative_call_2()
x86/dumpstack: Fix show_stack() task pointer regression
x86/dumpstack: Remove dump_trace() and related callbacks
x86/dumpstack: Convert show_trace_log_lvl() to use the new unwinder
oprofile/x86: Convert x86_backtrace() to use the new unwinder
x86/stacktrace: Convert save_stack_trace_*() to use the new unwinder
perf/x86: Convert perf_callchain_kernel() to use the new unwinder
x86/unwind: Add new unwind interface and implementations
x86/dumpstack: Remove NULL task pointer convention
fork: Optimize task creation by caching two thread stacks per CPU if CONFIG_VMAP_STACK=y
sched/core: Free the stack early if CONFIG_THREAD_INFO_IN_TASK
lib/syscall: Pin the task stack in collect_syscall()
x86/process: Pin the target stack in get_wchan()
x86/dumpstack: Pin the target stack when dumping it
kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function
sched/core: Add try_get_task_stack() and put_task_stack()
x86/entry/64: Fix a minor comment rebase error
iommu/amd: Don't put completion-wait semaphore on stack
...
Pull perf updates from Ingo Molnar:
"The main kernel side changes were:
- uprobes enhancements (Masami Hiramatsu)
- Uncore group events enhancements (David Carrillo-Cisneros)
- x86 Intel: Add support for Skylake server uncore PMUs (Kan Liang)
- x86 Intel: LBR cleanups and enhancements, for better branch
annotation tracking (Peter Zijlstra)
- x86 Intel: Add support for PTWRITE and power event tracing
(Alexander Shishkin)
- ... various fixes, cleanups and smaller enhancements.
Lots of tooling changes - a couple of highlights:
- Support event group view with hierarchy mode in 'perf top' and
'perf report' (Namhyung Kim)
e.g.:
$ perf record -e '{cycles,instructions}' make
$ perf report --hierarchy --stdio
...
# Overhead Command / Shared Object / Symbol
# ...................... ..................................
...
25.74% 27.18%sh
19.96% 24.14%libc-2.24.so
9.55% 14.64%[.] __strcmp_sse2
1.54% 0.00%[.] __tfind
1.07% 1.13%[.] _int_malloc
0.95% 0.00%[.] __strchr_sse2
0.89% 1.39%[.] __tsearch
0.76% 0.00%[.] strlen
- Add branch stack / basic block info to 'perf annotate --stdio',
where for each branch, we add an asm comment after the instruction
with information on how often it was taken and predicted. See
example with color output at:
http://vger.kernel.org/~acme/perf/annotate_basic_blocks.png
(Peter Zijlstra)
- Add support for using symbols in address filters with Intel PT and
ARM CoreSight (hardware assisted tracing facilities) (Adrian
Hunter, Mathieu Poirier)
- Add support for interacting with Coresight PMU ETMs/PTMs, that are
IP blocks to perform hardware assisted tracing on a ARM CPU core
(Mathieu Poirier)
- Support generating cross arch probes, i.e. if you specify a vmlinux
file for different arch than the one in the host machine,
$ perf probe --definition function_name args
will generate the probe definition string needed to append to the
target machine /sys/kernel/debug/tracing/kprobes_events file, using
scripting (Masami Hiramatsu).
- Allow configuring the default 'perf report -s' sort order in
~/.perfconfig, for instance, "sym,dso" may be more fitting for
kernel developers. (Arnaldo Carvalho de Melo)
- ... plus lots of other changes, refactorings, features and fixes"
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (149 commits)
perf tests: Add dwarf unwind test for powerpc
perf probe: Match linkage name with mangled name
perf probe: Fix to cut off incompatible chars from group name
perf probe: Skip if the function address is 0
perf probe: Ignore the error of finding inline instance
perf intel-pt: Fix decoding when there are address filters
perf intel-pt: Enable decoder to handle TIP.PGD with missing IP
perf intel-pt: Read address filter from AUXTRACE_INFO event
perf intel-pt: Record address filter in AUXTRACE_INFO event
perf intel-pt: Add a helper function for processing AUXTRACE_INFO
perf intel-pt: Fix missing error codes processing auxtrace_info
perf intel-pt: Add support for recording the max non-turbo ratio
perf intel-pt: Fix snapshot overlap detection decoder errors
perf probe: Increase debug level of SDT debug messages
perf record: Add support for using symbols in address filters
perf symbols: Add dso__last_symbol()
perf record: Fix error paths
perf record: Rename label 'out_symbol_exit'
perf script: Fix vanished idle symbols
perf evsel: Add support for address filters
...
Pull locking updates from Ingo Molnar:
"The main changes in this cycle were:
- rwsem micro-optimizations (Davidlohr Bueso)
- Improve the implementation and optimize the performance of
percpu-rwsems. (Peter Zijlstra.)
- Convert all lglock users to better facilities such as percpu-rwsems
or percpu-spinlocks and remove lglocks. (Peter Zijlstra)
- Remove the ticket (spin)lock implementation. (Peter Zijlstra)
- Korean translation of memory-barriers.txt and related fixes to the
English document. (SeongJae Park)
- misc fixes and cleanups"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
x86/cmpxchg, locking/atomics: Remove superfluous definitions
x86, locking/spinlocks: Remove ticket (spin)lock implementation
locking/lglock: Remove lglock implementation
stop_machine: Remove stop_cpus_lock and lg_double_lock/unlock()
fs/locks: Use percpu_down_read_preempt_disable()
locking/percpu-rwsem: Add down_read_preempt_disable()
fs/locks: Replace lg_local with a per-cpu spinlock
fs/locks: Replace lg_global with a percpu-rwsem
locking/percpu-rwsem: Add DEFINE_STATIC_PERCPU_RWSEMand percpu_rwsem_assert_held()
locking/pv-qspinlock: Use cmpxchg_release() in __pv_queued_spin_unlock()
locking/rwsem, x86: Drop a bogus cc clobber
futex: Add some more function commentry
locking/hung_task: Show all locks
locking/rwsem: Scan the wait_list for readers only once
locking/rwsem: Remove a few useless comments
locking/rwsem: Return void in __rwsem_mark_wake()
locking, rcu, cgroup: Avoid synchronize_sched() in __cgroup_procs_write()
locking/Documentation: Add Korean translation
locking/Documentation: Fix a typo of example result
locking/Documentation: Fix wrong section reference
...
Pull core SMP updates from Ingo Molnar:
"Two main change is generic vCPU pinning and physical CPU SMP-call
support, for Xen to be able to perform certain calls on specific
physical CPUs - by Juergen Gross"
* 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
smp: Allocate smp_call_on_cpu() workqueue on stack too
hwmon: Use smp_call_on_cpu() for dell-smm i8k
dcdbas: Make use of smp_call_on_cpu()
xen: Add xen_pin_vcpu() to support calling functions on a dedicated pCPU
smp: Add function to execute a function synchronously on a CPU
virt, sched: Add generic vCPU pinning support
xen: Sync xen header
Pull RCU updates from Ingo Molnar:
"The main changes in this cycle were:
- Expedited grace-period changes, most notably avoiding having user
threads drive expedited grace periods, using a workqueue instead.
- Miscellaneous fixes, including a performance fix for lists that was
sent with the lists modifications.
- CPU hotplug updates, most notably providing exact CPU-online
tracking for RCU. This will in turn allow removal of the checks
supporting RCU's prior heuristic that was based on the assumption
that CPUs would take no longer than one jiffy to come online.
- Torture-test updates.
- Documentation updates"
* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits)
list: Expand list_first_entry_or_null()
torture: TOROUT_STRING(): Insert a space between flag and message
rcuperf: Consistently insert space between flag and message
rcutorture: Print out barrier error as document says
torture: Add task state to writer-task stall printk()s
torture: Convert torture_shutdown() to hrtimer
rcutorture: Convert to hotplug state machine
cpu/hotplug: Get rid of CPU_STARTING reference
rcu: Provide exact CPU-online tracking for RCU
rcu: Avoid redundant quiescent-state chasing
rcu: Don't use modular infrastructure in non-modular code
sched: Make wake_up_nohz_cpu() handle CPUs going offline
rcu: Use rcu_gp_kthread_wake() to wake up grace period kthreads
rcu: Use RCU's online-CPU state for expedited IPI retry
rcu: Exclude RCU-offline CPUs from expedited grace periods
rcu: Make expedited RCU CPU stall warnings respond to controls
rcu: Stop disabling expedited RCU CPU stall warnings
rcu: Drive expedited grace periods from workqueue
rcu: Consolidate expedited grace period machinery
documentation: Record reason for rcu_head two-byte alignment
...
- Add a mechanism for passing hints from the scheduler to cpufreq governors
via their utilization update callbacks and use it to introduce "IOwait
boosting" into the schedutil governor and intel_pstate that will make them
boost performance if the enqueued task was previously waiting on I/O
(Rafael Wysocki).
- Fix a schedutil governor problem that causes it to overestimate utilization
if SMT is in use (Steve Muckle).
- Update defconfigs trying to use the schedutil governor as a module which is
not possible any more (Javier Martinez Canillas).
- Update the intel_pstate's pstate_sample tracepoint to take "IOwait boosting"
into account (Srinivas Pandruvada).
- Fix a problem in the cpufreq core causing it to mishandle the initialization
of CPUs registered after the cpufreq driver (Viresh Kumar, Rafael Wysocki).
- Make the cpufreq-dt driver support per-policy governor tunables, clean it
up and update its Kconfig description (Viresh Kumar).
- Add support for more ARM platforms to the cpufreq-dt driver (Chanwoo Choi,
Dave Gerlach, Geert Uytterhoeven).
- Make the cpufreq CPPC driver report frequencies in KHz to avoid user space
compatiblility issues (Al Stone, Hoan Tran).
- Clean up a few cpufreq drivers (st, kirkwood, SCPI) a bit (Colin Ian King,
Markus Elfring).
- Constify some local structures in the intel_pstate driver (Julia Lawall).
- Add a Documentation/cpu-freq/ entry to MAINTAINERS (Jean Delvare).
- Add support for PM domain removal to the generic power domains (genpd)
framework, add new DT helper functions to it and make it always enable
debugfs support if available (Jon Hunter, Tomeu Vizoso).
- Clean up the generic power domains (genpd) framework and make it avoid
measuring power-on and power-off latencies during system-wide PM transitions
(Ulf Hansson).
- Add support for the RockChip DFI controller and the rk3399 DMC to the
devfreq framework (Lin Huang, Axel Lin, Arnd Bergmann).
- Add COMPILE_TEST to the devfreq framework (Krzysztof Kozlowski, Stephen
Rothwell).
- Fix a minor issue in the exynos-ppmu devfreq driver and fix up devfreq
Kconfig indentation style (Wei Yongjun, Jisheng Zhang).
- Fix the system suspend interface to make suspend-to-idle work if platform
suspend operations have not been registered (Sudeep Holla).
- Make it possible to use hibernation with PAGE_POISONING_ZERO enabled
(Anisse Astier).
- Increas the default timeout of the system suspend/resume watchdog and make it
depend on EXPERT (Chen Yu).
- Make the operating performance points (OPP) framework avoid using OPPs that
aren't supported by the platform and fix a build warning in it (Dave Gerlach,
Arnd Bergmann).
- Fix the ARM cpuidle driver's return value (Christophe Jaillet).
- Make the SmartReflex AVS (Adaptive Voltage Scaling) driver use more common
logging style (Joe Perches).
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Merge tag 'pm-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management updates from Rafael Wysocki:
"Traditionally, cpufreq is the area with the greatest number of
changes, but there are fewer of them than last time. There also is
some activity in the generic power domains and the devfreq frameworks,
a couple of system suspend and hibernation fixes and some assorted
changes in other places.
One new feature is the cpufreq change to allow the scheduler to pass
hints to the governors' utilization update callbacks and some code
rework based on that. Another one is the support for domain removal in
the generic power domains framework. Also it is now possible to use
hibernation with PAGE_POISONING_ZERO enabled and devfreq supports the
RockChip DFI controller and the rk3399 DMC.
The rest of the changes is mostly fixes and cleanups in a number of
places.
Specifics:
- Add a mechanism for passing hints from the scheduler to cpufreq
governors via their utilization update callbacks and use it to
introduce "IOwait boosting" into the schedutil governor and
intel_pstate that will make them boost performance if the enqueued
task was previously waiting on I/O (Rafael Wysocki).
- Fix a schedutil governor problem that causes it to overestimate
utilization if SMT is in use (Steve Muckle).
- Update defconfigs trying to use the schedutil governor as a module
which is not possible any more (Javier Martinez Canillas).
- Update the intel_pstate's pstate_sample tracepoint to take "IOwait
boosting" into account (Srinivas Pandruvada).
- Fix a problem in the cpufreq core causing it to mishandle the
initialization of CPUs registered after the cpufreq driver (Viresh
Kumar, Rafael Wysocki).
- Make the cpufreq-dt driver support per-policy governor tunables,
clean it up and update its Kconfig description (Viresh Kumar).
- Add support for more ARM platforms to the cpufreq-dt driver
(Chanwoo Choi, Dave Gerlach, Geert Uytterhoeven).
- Make the cpufreq CPPC driver report frequencies in KHz to avoid
user space compatiblility issues (Al Stone, Hoan Tran).
- Clean up a few cpufreq drivers (st, kirkwood, SCPI) a bit (Colin
Ian King, Markus Elfring).
- Constify some local structures in the intel_pstate driver (Julia
Lawall).
- Add a Documentation/cpu-freq/ entry to MAINTAINERS (Jean Delvare).
- Add support for PM domain removal to the generic power domains
(genpd) framework, add new DT helper functions to it and make it
always enable debugfs support if available (Jon Hunter, Tomeu
Vizoso).
- Clean up the generic power domains (genpd) framework and make it
avoid measuring power-on and power-off latencies during system-wide
PM transitions (Ulf Hansson).
- Add support for the RockChip DFI controller and the rk3399 DMC to
the devfreq framework (Lin Huang, Axel Lin, Arnd Bergmann).
- Add COMPILE_TEST to the devfreq framework (Krzysztof Kozlowski,
Stephen Rothwell).
- Fix a minor issue in the exynos-ppmu devfreq driver and fix up
devfreq Kconfig indentation style (Wei Yongjun, Jisheng Zhang).
- Fix the system suspend interface to make suspend-to-idle work if
platform suspend operations have not been registered (Sudeep
Holla).
- Make it possible to use hibernation with PAGE_POISONING_ZERO
enabled (Anisse Astier).
- Increas the default timeout of the system suspend/resume watchdog
and make it depend on EXPERT (Chen Yu).
- Make the operating performance points (OPP) framework avoid using
OPPs that aren't supported by the platform and fix a build warning
in it (Dave Gerlach, Arnd Bergmann).
- Fix the ARM cpuidle driver's return value (Christophe Jaillet).
- Make the SmartReflex AVS (Adaptive Voltage Scaling) driver use more
common logging style (Joe Perches)"
* tag 'pm-4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (58 commits)
PM / OPP: Don't support OPP if it provides supported-hw but platform does not
cpufreq: st: add missing \n to end of dev_err message
cpufreq: kirkwood: add missing \n to end of dev_err messages
PM / Domains: Rename pm_genpd_sync_poweron|poweroff()
PM / Domains: Don't measure latency of ->power_on|off() during system PM
PM / Domains: Remove redundant system PM callbacks
PM / Domains: Simplify detaching a device from its genpd
PM / devfreq: rk3399_dmc: Remove explictly regulator_put call in .remove
PM / devfreq: rockchip: add PM_DEVFREQ_EVENT dependency
PM / OPP: avoid maybe-uninitialized warning
PM / Domains: Allow holes in genpd_data.domains array
cpufreq: CPPC: Avoid overflow when calculating desired_perf
cpufreq: ti: Use generic platdev driver
cpufreq: intel_pstate: Add io_boost trace
partial revert of "PM / devfreq: Add COMPILE_TEST for build coverage"
cpufreq: intel_pstate: Use IOWAIT flag in Atom algorithm
cpufreq: schedutil: Add iowait boosting
cpufreq / sched: SCHED_CPUFREQ_IOWAIT flag to indicate iowait condition
PM / Domains: Add support for removing nested PM domains by provider
PM / Domains: Add support for removing PM domains
...
- Support for execute-only page permissions
- Support for hibernate and DEBUG_PAGEALLOC
- Support for heterogeneous systems with mismatches cache line sizes
- Errata workarounds (A53 843419 update and QorIQ A-008585 timer bug)
- arm64 PMU perf updates, including cpumasks for heterogeneous systems
- Set UTS_MACHINE for building rpm packages
- Yet another head.S tidy-up
- Some cleanups and refactoring, particularly in the NUMA code
- Lots of random, non-critical fixes across the board
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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 updates from Will Deacon:
"It's a bit all over the place this time with no "killer feature" to
speak of. Support for mismatched cache line sizes should help people
seeing whacky JIT failures on some SoCs, and the big.LITTLE perf
updates have been a long time coming, but a lot of the changes here
are cleanups.
We stray outside arch/arm64 in a few areas: the arch/arm/ arch_timer
workaround is acked by Russell, the DT/OF bits are acked by Rob, the
arch_timer clocksource changes acked by Marc, CPU hotplug by tglx and
jump_label by Peter (all CC'd).
Summary:
- Support for execute-only page permissions
- Support for hibernate and DEBUG_PAGEALLOC
- Support for heterogeneous systems with mismatches cache line sizes
- Errata workarounds (A53 843419 update and QorIQ A-008585 timer bug)
- arm64 PMU perf updates, including cpumasks for heterogeneous systems
- Set UTS_MACHINE for building rpm packages
- Yet another head.S tidy-up
- Some cleanups and refactoring, particularly in the NUMA code
- Lots of random, non-critical fixes across the board"
* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (100 commits)
arm64: tlbflush.h: add __tlbi() macro
arm64: Kconfig: remove SMP dependence for NUMA
arm64: Kconfig: select OF/ACPI_NUMA under NUMA config
arm64: fix dump_backtrace/unwind_frame with NULL tsk
arm/arm64: arch_timer: Use archdata to indicate vdso suitability
arm64: arch_timer: Work around QorIQ Erratum A-008585
arm64: arch_timer: Add device tree binding for A-008585 erratum
arm64: Correctly bounds check virt_addr_valid
arm64: migrate exception table users off module.h and onto extable.h
arm64: pmu: Hoist pmu platform device name
arm64: pmu: Probe default hw/cache counters
arm64: pmu: add fallback probe table
MAINTAINERS: Update ARM PMU PROFILING AND DEBUGGING entry
arm64: Improve kprobes test for atomic sequence
arm64/kvm: use alternative auto-nop
arm64: use alternative auto-nop
arm64: alternative: add auto-nop infrastructure
arm64: lse: convert lse alternatives NOP padding to use __nops
arm64: barriers: introduce nops and __nops macros for NOP sequences
arm64: sysreg: replace open-coded mrs_s/msr_s with {read,write}_sysreg_s
...
* pm-cpufreq: (24 commits)
cpufreq: st: add missing \n to end of dev_err message
cpufreq: kirkwood: add missing \n to end of dev_err messages
cpufreq: CPPC: Avoid overflow when calculating desired_perf
cpufreq: ti: Use generic platdev driver
cpufreq: intel_pstate: Add io_boost trace
cpufreq: intel_pstate: Use IOWAIT flag in Atom algorithm
cpufreq: schedutil: Add iowait boosting
cpufreq / sched: SCHED_CPUFREQ_IOWAIT flag to indicate iowait condition
cpufreq: CPPC: Force reporting values in KHz to fix user space interface
cpufreq: create link to policy only for registered CPUs
intel_pstate: constify local structures
cpufreq: dt: Support governor tunables per policy
cpufreq: dt: Update kconfig description
cpufreq: dt: Remove unused code
MAINTAINERS: Add Documentation/cpu-freq/
cpufreq: dt: Add support for r8a7792
cpufreq / sched: ignore SMT when determining max cpu capacity
cpufreq: Drop unnecessary check from cpufreq_policy_alloc()
ARM: multi_v7_defconfig: Don't attempt to enable schedutil governor as module
ARM: exynos_defconfig: Don't attempt to enable schedutil governor as module
...
CAI Qian <caiqian@redhat.com> pointed out that the semantics
of shared subtrees make it possible to create an exponentially
increasing number of mounts in a mount namespace.
mkdir /tmp/1 /tmp/2
mount --make-rshared /
for i in $(seq 1 20) ; do mount --bind /tmp/1 /tmp/2 ; done
Will create create 2^20 or 1048576 mounts, which is a practical problem
as some people have managed to hit this by accident.
As such CVE-2016-6213 was assigned.
Ian Kent <raven@themaw.net> described the situation for autofs users
as follows:
> The number of mounts for direct mount maps is usually not very large because of
> the way they are implemented, large direct mount maps can have performance
> problems. There can be anywhere from a few (likely case a few hundred) to less
> than 10000, plus mounts that have been triggered and not yet expired.
>
> Indirect mounts have one autofs mount at the root plus the number of mounts that
> have been triggered and not yet expired.
>
> The number of autofs indirect map entries can range from a few to the common
> case of several thousand and in rare cases up to between 30000 and 50000. I've
> not heard of people with maps larger than 50000 entries.
>
> The larger the number of map entries the greater the possibility for a large
> number of active mounts so it's not hard to expect cases of a 1000 or somewhat
> more active mounts.
So I am setting the default number of mounts allowed per mount
namespace at 100,000. This is more than enough for any use case I
know of, but small enough to quickly stop an exponential increase
in mounts. Which should be perfect to catch misconfigurations and
malfunctioning programs.
For anyone who needs a higher limit this can be changed by writing
to the new /proc/sys/fs/mount-max sysctl.
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
The code performing irqtime nsecs stats flushing to kcpustat is roughly
the same for hardirq and softirq. So lets consolidate that common code.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474849761-12678-6-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The irqtime accounting currently implement its own ad hoc implementation
of u64_stats API. Lets rather consolidate it with the appropriate
library.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474849761-12678-5-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The callers of the functions performing irqtime kcpustat updates have
IRQS disabled, no need to disable them again.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474849761-12678-3-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We can safely use the preempt-unsafe accessors for irqtime when we
flush its counters to kcpustat as IRQs are disabled at this time.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1474849761-12678-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
While going through enqueue/dequeue to review the movement of
set_curr_task() I noticed that the (2nd) update_min_vruntime() call in
dequeue_entity() is suspect.
It turns out, its actually wrong because it will consider
cfs_rq->curr, which could be the entry we just normalized. This mixes
different vruntime forms and leads to fail.
The purpose of the second update_min_vruntime() is to move
min_vruntime forward if the entity we just removed is the one that was
holding it back; _except_ for the DEQUEUE_SAVE case, because then we
know its a temporary removal and it will come back.
However, since we do put_prev_task() _after_ dequeue(), cfs_rq->curr
will still be set (and per the above, can be tranformed into a
different unit), so update_min_vruntime() should also consider
curr->on_rq. This also fixes another corner case where the enqueue
(which also does update_curr()->update_min_vruntime()) happens on the
rq->lock break in schedule(), between dequeue and put_prev_task.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Fixes: 1e87623178 ("sched: Fix ->min_vruntime calculation in dequeue_entity()")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Provide SCHED_WARN_ON as wrapper for WARN_ON_ONCE() to avoid
CONFIG_SCHED_DEBUG wrappery.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Almost all scheduler functions update state with the following
pattern:
if (queued)
dequeue_task(rq, p, DEQUEUE_SAVE);
if (running)
put_prev_task(rq, p);
/* update state */
if (queued)
enqueue_task(rq, p, ENQUEUE_RESTORE);
if (running)
set_curr_task(rq, p);
set_user_nice() however misses the running part, cure this.
This was found by asserting we never enqueue 'current'.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Now that the ia64 only set_curr_task() symbol is gone, provide a
helper just like put_prev_task().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rename the ia64 only set_curr_task() function to free up the name.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a task switches to fair scheduling class, the period between now
and the last update of its utilization is accounted as running time
whatever happened during this period. This incorrect accounting applies
to the task and also to the task group branch.
When changing the property of a running task like its list of allowed
CPUs or its scheduling class, we follow the sequence:
- dequeue task
- put task
- change the property
- set task as current task
- enqueue task
The end of the sequence doesn't follow the normal sequence (as per
__schedule()) which is:
- enqueue a task
- then set the task as current task.
This incorrectordering is the root cause of incorrect utilization accounting.
Update the sequence to follow the right one:
- dequeue task
- put task
- change the property
- enqueue task
- set task as current task
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Morten.Rasmussen@arm.com
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Cc: dietmar.eggemann@arm.com
Cc: linaro-kernel@lists.linaro.org
Cc: pjt@google.com
Cc: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1473666472-13749-8-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
select_idle_siblings() is a known pain point for a number of
workloads; it either does too much or not enough and sometimes just
does plain wrong.
This rewrite attempts to address a number of issues (but sadly not
all).
The current code does an unconditional sched_domain iteration; with
the intent of finding an idle core (on SMT hardware). The problems
which this patch tries to address are:
- its pointless to look for idle cores if the machine is real busy;
at which point you're just wasting cycles.
- it's behaviour is inconsistent between SMT and !SMT hardware in
that !SMT hardware ends up doing a scan for any idle CPU in the LLC
domain, while SMT hardware does a scan for idle cores and if that
fails, falls back to a scan for idle threads on the 'target' core.
The new code replaces the sched_domain scan with 3 explicit scans:
1) search for an idle core in the LLC
2) search for an idle CPU in the LLC
3) search for an idle thread in the 'target' core
where 1 and 3 are conditional on SMT support and 1 and 2 have runtime
heuristics to skip the step.
Step 1) is conditional on sd_llc_shared->has_idle_cores; when a cpu
goes idle and sd_llc_shared->has_idle_cores is false, we scan all SMT
siblings of the CPU going idle. Similarly, we clear
sd_llc_shared->has_idle_cores when we fail to find an idle core.
Step 2) tracks the average cost of the scan and compares this to the
average idle time guestimate for the CPU doing the wakeup. There is a
significant fudge factor involved to deal with the variability of the
averages. Esp. hackbench was sensitive to this.
Step 3) is unconditional; we assume (also per step 1) that scanning
all SMT siblings in a core is 'cheap'.
With this; SMT systems gain step 2, which cures a few benchmarks --
notably one from Facebook.
One 'feature' of the sched_domain iteration, which we preserve in the
new code, is that it would start scanning from the 'target' CPU,
instead of scanning the cpumask in cpu id order. This avoids multiple
CPUs in the LLC scanning for idle to gang up and find the same CPU
quite as much. The down side is that tasks can end up hopping across
the LLC for no apparent reason.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Move the nr_busy_cpus thing from its hacky sd->parent->groups->sgc
location into the much more natural sched_domain_shared location.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
