Pull cgroup fixes from Tejun Heo:
"This has an unusually high density of tricky fixes:
- task_get_css() could deadlock when it races against a dying cgroup.
- cgroup.procs didn't list thread group leaders with live threads.
This could mislead readers to think that a cgroup is empty when
it's not. Fixed by making PROCS iterator include dead tasks. I made
a couple mistakes making this change and this pull request contains
a couple follow-up patches.
- When cpusets run out of online cpus, it updates cpusmasks of member
tasks in bizarre ways. Joel improved the behavior significantly"
* 'for-5.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cpuset: restore sanity to cpuset_cpus_allowed_fallback()
cgroup: Fix css_task_iter_advance_css_set() cset skip condition
cgroup: css_task_iter_skip()'d iterators must be advanced before accessed
cgroup: Include dying leaders with live threads in PROCS iterations
cgroup: Implement css_task_iter_skip()
cgroup: Call cgroup_release() before __exit_signal()
docs cgroups: add another example size for hugetlb
cgroup: Use css_tryget() instead of css_tryget_online() in task_get_css()
In the case that a process is constrained by taskset(1) (i.e.
sched_setaffinity(2)) to a subset of available cpus, and all of those are
subsequently offlined, the scheduler will set tsk->cpus_allowed to
the current value of task_cs(tsk)->effective_cpus.
This is done via a call to do_set_cpus_allowed() in the context of
cpuset_cpus_allowed_fallback() made by the scheduler when this case is
detected. This is the only call made to cpuset_cpus_allowed_fallback()
in the latest mainline kernel.
However, this is not sane behavior.
I will demonstrate this on a system running the latest upstream kernel
with the following initial configuration:
# grep -i cpu /proc/$$/status
Cpus_allowed: ffffffff,fffffff
Cpus_allowed_list: 0-63
(Where cpus 32-63 are provided via smt.)
If we limit our current shell process to cpu2 only and then offline it
and reonline it:
# taskset -p 4 $$
pid 2272's current affinity mask: ffffffffffffffff
pid 2272's new affinity mask: 4
# echo off > /sys/devices/system/cpu/cpu2/online
# dmesg | tail -3
[ 2195.866089] process 2272 (bash) no longer affine to cpu2
[ 2195.872700] IRQ 114: no longer affine to CPU2
[ 2195.879128] smpboot: CPU 2 is now offline
# echo on > /sys/devices/system/cpu/cpu2/online
# dmesg | tail -1
[ 2617.043572] smpboot: Booting Node 0 Processor 2 APIC 0x4
We see that our current process now has an affinity mask containing
every cpu available on the system _except_ the one we originally
constrained it to:
# grep -i cpu /proc/$$/status
Cpus_allowed: ffffffff,fffffffb
Cpus_allowed_list: 0-1,3-63
This is not sane behavior, as the scheduler can now not only place the
process on previously forbidden cpus, it can't even schedule it on
the cpu it was originally constrained to!
Other cases result in even more exotic affinity masks. Take for instance
a process with an affinity mask containing only cpus provided by smt at
the moment that smt is toggled, in a configuration such as the following:
# taskset -p f000000000 $$
# grep -i cpu /proc/$$/status
Cpus_allowed: 000000f0,00000000
Cpus_allowed_list: 36-39
A double toggle of smt results in the following behavior:
# echo off > /sys/devices/system/cpu/smt/control
# echo on > /sys/devices/system/cpu/smt/control
# grep -i cpus /proc/$$/status
Cpus_allowed: ffffff00,ffffffff
Cpus_allowed_list: 0-31,40-63
This is even less sane than the previous case, as the new affinity mask
excludes all smt-provided cpus with ids less than those that were
previously in the affinity mask, as well as those that were actually in
the mask.
With this patch applied, both of these cases end in the following state:
# grep -i cpu /proc/$$/status
Cpus_allowed: ffffffff,ffffffff
Cpus_allowed_list: 0-63
The original policy is discarded. Though not ideal, it is the simplest way
to restore sanity to this fallback case without reinventing the cpuset
wheel that rolls down the kernel just fine in cgroup v2. A user who wishes
for the previous affinity mask to be restored in this fallback case can use
that mechanism instead.
This patch modifies scheduler behavior by instead resetting the mask to
task_cs(tsk)->cpus_allowed by default, and cpu_possible mask in legacy
mode. I tested the cases above on both modes.
Note that the scheduler uses this fallback mechanism if and only if
_every_ other valid avenue has been traveled, and it is the last resort
before calling BUG().
Suggested-by: Waiman Long <longman@redhat.com>
Suggested-by: Phil Auld <pauld@redhat.com>
Signed-off-by: Joel Savitz <jsavitz@redhat.com>
Acked-by: Phil Auld <pauld@redhat.com>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
While adding handling for dying task group leaders c03cd7738a
("cgroup: Include dying leaders with live threads in PROCS
iterations") added an inverted cset skip condition to
css_task_iter_advance_css_set(). It should skip cset if it's
completely empty but was incorrectly testing for the inverse condition
for the dying_tasks list. Fix it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: c03cd7738a ("cgroup: Include dying leaders with live threads in PROCS iterations")
Reported-by: syzbot+d4bba5ccd4f9a2a68681@syzkaller.appspotmail.com
There's some discussion on how to do this the best, and Tejun prefers
that BFQ just create the file itself instead of having cgroups support
a symlink feature.
Hence revert commit 54b7b868e8 and 19e9da9e86 for 5.2, and this
can be done properly for 5.3.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit enables a cftype to have a symlink (of any name) that
points to the file associated with the cftype.
Signed-off-by: Angelo Ruocco <angeloruocco90@gmail.com>
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
b636fd38dc ("cgroup: Implement css_task_iter_skip()") introduced
css_task_iter_skip() which is used to fix task iterations skipping
dying threadgroup leaders with live threads. Skipping is implemented
as a subportion of full advancing but css_task_iter_next() forgot to
fully advance a skipped iterator before determining the next task to
visit causing it to return invalid task pointers.
Fix it by making css_task_iter_next() fully advance the iterator if it
has been skipped since the previous iteration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: syzbot
Link: http://lkml.kernel.org/r/00000000000097025d058a7fd785@google.com
Fixes: b636fd38dc ("cgroup: Implement css_task_iter_skip()")
memory.stat and other files already consider subtrees in their output, and
we should too in order to not present an inconsistent interface.
The current situation is fairly confusing, because people interacting with
cgroups expect hierarchical behaviour in the vein of memory.stat,
cgroup.events, and other files. For example, this causes confusion when
debugging reclaim events under low, as currently these always read "0" at
non-leaf memcg nodes, which frequently causes people to misdiagnose breach
behaviour. The same confusion applies to other counters in this file when
debugging issues.
Aggregation is done at write time instead of at read-time since these
counters aren't hot (unlike memory.stat which is per-page, so it does it
at read time), and it makes sense to bundle this with the file
notifications.
After this patch, events are propagated up the hierarchy:
[root@ktst ~]# cat /sys/fs/cgroup/system.slice/memory.events
low 0
high 0
max 0
oom 0
oom_kill 0
[root@ktst ~]# systemd-run -p MemoryMax=1 true
Running as unit: run-r251162a189fb4562b9dabfdc9b0422f5.service
[root@ktst ~]# cat /sys/fs/cgroup/system.slice/memory.events
low 0
high 0
max 7
oom 1
oom_kill 1
As this is a change in behaviour, this can be reverted to the old
behaviour by mounting with the `memory_localevents' flag set. However, we
use the new behaviour by default as there's a lack of evidence that there
are any current users of memory.events that would find this change
undesirable.
akpm: this is a behaviour change, so Cc:stable. THis is so that
forthcoming distros which use cgroup v2 are more likely to pick up the
revised behaviour.
Link: http://lkml.kernel.org/r/20190208224419.GA24772@chrisdown.name
Signed-off-by: Chris Down <chris@chrisdown.name>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
CSS_TASK_ITER_PROCS currently iterates live group leaders; however,
this means that a process with dying leader and live threads will be
skipped. IOW, cgroup.procs might be empty while cgroup.threads isn't,
which is confusing to say the least.
Fix it by making cset track dying tasks and include dying leaders with
live threads in PROCS iteration.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-and-tested-by: Topi Miettinen <toiwoton@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
When a task is moved out of a cset, task iterators pointing to the
task are advanced using the normal css_task_iter_advance() call. This
is fine but we'll be tracking dying tasks on csets and thus moving
tasks from cset->tasks to (to be added) cset->dying_tasks. When we
remove a task from cset->tasks, if we advance the iterators, they may
move over to the next cset before we had the chance to add the task
back on the dying list, which can allow the task to escape iteration.
This patch separates out skipping from advancing. Skipping only moves
the affected iterators to the next pointer rather than fully advancing
it and the following advancing will recognize that the cursor has
already been moved forward and do the rest of advancing. This ensures
that when a task moves from one list to another in its cset, as long
as it moves in the right direction, it's always visible to iteration.
This doesn't cause any visible behavior changes.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Add SPDX license identifiers to all files which:
- Have no license information of any form
- Have EXPORT_.*_SYMBOL_GPL inside which was used in the
initial scan/conversion to ignore the file
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pressure metrics are already recorded and exposed in procfs for the
entire system, but any tool which monitors cgroup pressure has to
special case the root cgroup to read from procfs. This patch exposes
the already recorded pressure metrics on the root cgroup.
Link: http://lkml.kernel.org/r/20190510174938.3361741-1-dschatzberg@fb.com
Signed-off-by: Dan Schatzberg <dschatzberg@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Psi monitor aims to provide a low-latency short-term pressure detection
mechanism configurable by users. It allows users to monitor psi metrics
growth and trigger events whenever a metric raises above user-defined
threshold within user-defined time window.
Time window and threshold are both expressed in usecs. Multiple psi
resources with different thresholds and window sizes can be monitored
concurrently.
Psi monitors activate when system enters stall state for the monitored
psi metric and deactivate upon exit from the stall state. While system
is in the stall state psi signal growth is monitored at a rate of 10
times per tracking window. Min window size is 500ms, therefore the min
monitoring interval is 50ms. Max window size is 10s with monitoring
interval of 1s.
When activated psi monitor stays active for at least the duration of one
tracking window to avoid repeated activations/deactivations when psi
signal is bouncing.
Notifications to the users are rate-limited to one per tracking window.
Link: http://lkml.kernel.org/r/20190319235619.260832-8-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull cgroup updates from Tejun Heo:
"This includes Roman's cgroup2 freezer implementation.
It's a separate machanism from cgroup1 freezer. Instead of blocking
user tasks in arbitrary uninterruptible sleeps, the new implementation
extends jobctl stop - frozen tasks are trapped in jobctl stop until
thawed and can be killed and ptraced. Lots of thanks to Oleg for
sheperding the effort.
Other than that, there are a few trivial changes"
* 'for-5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: never call do_group_exit() with task->frozen bit set
kernel: cgroup: fix misuse of %x
cgroup: get rid of cgroup_freezer_frozen_exit()
cgroup: prevent spurious transition into non-frozen state
cgroup: Remove unused cgrp variable
cgroup: document cgroup v2 freezer interface
cgroup: add tracing points for cgroup v2 freezer
cgroup: make TRACE_CGROUP_PATH irq-safe
kselftests: cgroup: add freezer controller self-tests
kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy()
cgroup: cgroup v2 freezer
cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock
cgroup: implement __cgroup_task_count() helper
cgroup: rename freezer.c into legacy_freezer.c
cgroup: remove extra cgroup_migrate_finish() call
Pointers should be printed with %p or %px rather than
cast to unsigned long type and printed with %lx.
Change %lx to %p to print the pointers.
Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
A task should never enter the exit path with the task->frozen bit set.
Any frozen task must enter the signal handling loop and the only
way to escape is through cgroup_leave_frozen(true), which
unconditionally drops the task->frozen bit. So it means that
cgroyp_freezer_frozen_exit() has zero chances to be called and
has to be removed.
Let's put a WARN_ON_ONCE() instead of the cgroup_freezer_frozen_exit()
call to catch any potential leak of the task's frozen bit.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
If freezing of a cgroup races with waking of a task from
the frozen state (like waiting in vfork() or in do_signal_stop()),
a spurious transition of the cgroup state can happen.
The task enters cgroup_leave_frozen(true), the cgroup->nr_frozen_tasks
counter decrements, and the cgroup is switched to the unfrozen state.
To prevent it, let's reserve cgroup_leave_frozen(true) for
terminating processes and use cgroup_leave_frozen(false) otherwise.
To avoid busy-looping in the signal handling loop waiting
for JOBCTL_TRAP_FREEZE set from the cgroup freezing path,
let's do it explicitly in cgroup_leave_frozen(), if the task
is going to stay frozen.
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
The 'cgrp' is set but not used in commit <76f969e8948d8>
("cgroup: cgroup v2 freezer").
Remove it to avoid [-Wunused-but-set-variable] warning.
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Acked-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Add cgroup:cgroup_freeze and cgroup:cgroup_unfreeze events,
which are using the existing cgroup tracing infrastructure.
Add the cgroup_event event class, which is similar to the cgroup
class, but contains an additional integer field to store a new
value (the level field is dropped).
Also add two tracing events: cgroup_notify_populated and
cgroup_notify_frozen, which are raised in a generic way using
the TRACE_CGROUP_PATH() macro.
This allows to trace cgroup state transitions and is generally
helpful for debugging the cgroup freezer code.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
To use the TRACE_CGROUP_PATH() macro with css_set_lock
locked, let's make the macro irq-safe.
It's necessary in order to trace cgroup freezer state
transitions (frozen/not frozen), which are happening
with css_set_lock locked.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cgroup v1 implements the freezer controller, which provides an ability
to stop the workload in a cgroup and temporarily free up some
resources (cpu, io, network bandwidth and, potentially, memory)
for some other tasks. Cgroup v2 lacks this functionality.
This patch implements freezer for cgroup v2.
Cgroup v2 freezer tries to put tasks into a state similar to jobctl
stop. This means that tasks can be killed, ptraced (using
PTRACE_SEIZE*), and interrupted. It is possible to attach to
a frozen task, get some information (e.g. read registers) and detach.
It's also possible to migrate a frozen tasks to another cgroup.
This differs cgroup v2 freezer from cgroup v1 freezer, which mostly
tried to imitate the system-wide freezer. However uninterruptible
sleep is fine when all tasks are going to be frozen (hibernation case),
it's not the acceptable state for some subset of the system.
Cgroup v2 freezer is not supporting freezing kthreads.
If a non-root cgroup contains kthread, the cgroup still can be frozen,
but the kthread will remain running, the cgroup will be shown
as non-frozen, and the notification will not be delivered.
* PTRACE_ATTACH is not working because non-fatal signal delivery
is blocked in frozen state.
There are some interface differences between cgroup v1 and cgroup v2
freezer too, which are required to conform the cgroup v2 interface
design principles:
1) There is no separate controller, which has to be turned on:
the functionality is always available and is represented by
cgroup.freeze and cgroup.events cgroup control files.
2) The desired state is defined by the cgroup.freeze control file.
Any hierarchical configuration is allowed.
3) The interface is asynchronous. The actual state is available
using cgroup.events control file ("frozen" field). There are no
dedicated transitional states.
4) It's allowed to make any changes with the cgroup hierarchy
(create new cgroups, remove old cgroups, move tasks between cgroups)
no matter if some cgroups are frozen.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
No-objection-from-me-by: Oleg Nesterov <oleg@redhat.com>
Cc: kernel-team@fb.com
The number of descendant cgroups and the number of dying
descendant cgroups are currently synchronized using the cgroup_mutex.
The number of descendant cgroups will be required by the cgroup v2
freezer, which will use it to determine if a cgroup is frozen
(depending on total number of descendants and number of frozen
descendants). It's not always acceptable to grab the cgroup_mutex,
especially from quite hot paths (e.g. exit()).
To avoid this, let's additionally synchronize these counters using
the css_set_lock.
So, it's safe to read these counters with either cgroup_mutex or
css_set_lock locked, and for changing both locks should be acquired.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
The helper is identical to the existing cgroup_task_count()
except it doesn't take the css_set_lock by itself, assuming
that the caller does.
Also, move cgroup_task_count() implementation into
kernel/cgroup/cgroup.c, as there is nothing specific to cgroup v1.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
Freezer.c will contain an implementation of cgroup v2 freezer,
so let's rename the v1 freezer to avoid naming conflicts.
Signed-off-by: Roman Gushchin <guro@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: kernel-team@fb.com
Commit:
fc560a26ac ("cpuset: replace cpuset->stack_list with cpuset_for_each_descendant_pre()")
removed the local list (q) that was used to perform a top-down scan
of all cpusets; however, comments mentioning it were not updated.
Update comments to reflect current implementation.
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: cgroups@vger.kernel.org
Cc: lizefan@huawei.com
Link: http://lkml.kernel.org/r/20181219133445.31982-1-juri.lelli@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The callers of cgroup_migrate_prepare_dst() correctly call
cgroup_migrate_finish() for success and failure cases both. No need to
call it in cgroup_migrate_prepare_dst() in failure case.
Signed-off-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Pull vfs mount infrastructure updates from Al Viro:
"The rest of core infrastructure; no new syscalls in that pile, but the
old parts are switched to new infrastructure. At that point
conversions of individual filesystems can happen independently; some
are done here (afs, cgroup, procfs, etc.), there's also a large series
outside of that pile dealing with NFS (quite a bit of option-parsing
stuff is getting used there - it's one of the most convoluted
filesystems in terms of mount-related logics), but NFS bits are the
next cycle fodder.
It got seriously simplified since the last cycle; documentation is
probably the weakest bit at the moment - I considered dropping the
commit introducing Documentation/filesystems/mount_api.txt (cutting
the size increase by quarter ;-), but decided that it would be better
to fix it up after -rc1 instead.
That pile allows to do followup work in independent branches, which
should make life much easier for the next cycle. fs/super.c size
increase is unpleasant; there's a followup series that allows to
shrink it considerably, but I decided to leave that until the next
cycle"
* 'work.mount' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
afs: Use fs_context to pass parameters over automount
afs: Add fs_context support
vfs: Add some logging to the core users of the fs_context log
vfs: Implement logging through fs_context
vfs: Provide documentation for new mount API
vfs: Remove kern_mount_data()
hugetlbfs: Convert to fs_context
cpuset: Use fs_context
kernfs, sysfs, cgroup, intel_rdt: Support fs_context
cgroup: store a reference to cgroup_ns into cgroup_fs_context
cgroup1_get_tree(): separate "get cgroup_root to use" into a separate helper
cgroup_do_mount(): massage calling conventions
cgroup: stash cgroup_root reference into cgroup_fs_context
cgroup2: switch to option-by-option parsing
cgroup1: switch to option-by-option parsing
cgroup: take options parsing into ->parse_monolithic()
cgroup: fold cgroup1_mount() into cgroup1_get_tree()
cgroup: start switching to fs_context
ipc: Convert mqueue fs to fs_context
proc: Add fs_context support to procfs
...
This has been a slightly more active cycle than normal with ongoing core
changes and quite a lot of collected driver updates.
- Various driver fixes for bnxt_re, cxgb4, hns, mlx5, pvrdma, rxe
- A new data transfer mode for HFI1 giving higher performance
- Significant functional and bug fix update to the mlx5 On-Demand-Paging MR
feature
- A chip hang reset recovery system for hns
- Change mm->pinned_vm to an atomic64
- Update bnxt_re to support a new 57500 chip
- A sane netlink 'rdma link add' method for creating rxe devices and fixing
the various unregistration race conditions in rxe's unregister flow
- Allow lookup up objects by an ID over netlink
- Various reworking of the core to driver interface:
* Drivers should not assume umem SGLs are in PAGE_SIZE chunks
* ucontext is accessed via udata not other means
* Start to make the core code responsible for object memory
allocation
* Drivers should convert struct device to struct ib_device
via a helper
* Drivers have more tools to avoid use after unregister problems
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Pull rdma updates from Jason Gunthorpe:
"This has been a slightly more active cycle than normal with ongoing
core changes and quite a lot of collected driver updates.
- Various driver fixes for bnxt_re, cxgb4, hns, mlx5, pvrdma, rxe
- A new data transfer mode for HFI1 giving higher performance
- Significant functional and bug fix update to the mlx5
On-Demand-Paging MR feature
- A chip hang reset recovery system for hns
- Change mm->pinned_vm to an atomic64
- Update bnxt_re to support a new 57500 chip
- A sane netlink 'rdma link add' method for creating rxe devices and
fixing the various unregistration race conditions in rxe's
unregister flow
- Allow lookup up objects by an ID over netlink
- Various reworking of the core to driver interface:
- drivers should not assume umem SGLs are in PAGE_SIZE chunks
- ucontext is accessed via udata not other means
- start to make the core code responsible for object memory
allocation
- drivers should convert struct device to struct ib_device via a
helper
- drivers have more tools to avoid use after unregister problems"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (280 commits)
net/mlx5: ODP support for XRC transport is not enabled by default in FW
IB/hfi1: Close race condition on user context disable and close
RDMA/umem: Revert broken 'off by one' fix
RDMA/umem: minor bug fix in error handling path
RDMA/hns: Use GFP_ATOMIC in hns_roce_v2_modify_qp
cxgb4: kfree mhp after the debug print
IB/rdmavt: Fix concurrency panics in QP post_send and modify to error
IB/rdmavt: Fix loopback send with invalidate ordering
IB/iser: Fix dma_nents type definition
IB/mlx5: Set correct write permissions for implicit ODP MR
bnxt_re: Clean cq for kernel consumers only
RDMA/uverbs: Don't do double free of allocated PD
RDMA: Handle ucontext allocations by IB/core
RDMA/core: Fix a WARN() message
bnxt_re: fix the regression due to changes in alloc_pbl
IB/mlx4: Increase the timeout for CM cache
IB/core: Abort page fault handler silently during owning process exit
IB/mlx5: Validate correct PD before prefetch MR
IB/mlx5: Protect against prefetch of invalid MR
RDMA/uverbs: Store PR pointer before it is overwritten
...
Cgroup has a standardized poll/notification mechanism for waking all
pollers on all fds when a filesystem node changes. To allow polling for
custom events, add a .poll callback that can override the default.
This is in preparation for pollable cgroup pressure files which have
per-fd trigger configurations.
Link: http://lkml.kernel.org/r/20190124211518.244221-3-surenb@google.com
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Dennis Zhou <dennis@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull networking updates from David Miller:
"Here we go, another merge window full of networking and #ebpf changes:
1) Snoop DHCPACKS in batman-adv to learn MAC/IP pairs in the DHCP
range without dealing with floods of ARP traffic, from Linus
Lüssing.
2) Throttle buffered multicast packet transmission in mt76, from
Felix Fietkau.
3) Support adaptive interrupt moderation in ice, from Brett Creeley.
4) A lot of struct_size conversions, from Gustavo A. R. Silva.
5) Add peek/push/pop commands to bpftool, as well as bash completion,
from Stanislav Fomichev.
6) Optimize sk_msg_clone(), from Vakul Garg.
7) Add SO_BINDTOIFINDEX, from David Herrmann.
8) Be more conservative with local resends due to local congestion,
from Yuchung Cheng.
9) Allow vetoing of unsupported VXLAN FDBs, from Petr Machata.
10) Add health buffer support to devlink, from Eran Ben Elisha.
11) Add TXQ scheduling API to mac80211, from Toke Høiland-Jørgensen.
12) Add statistics to basic packet scheduler filter, from Cong Wang.
13) Add GRE tunnel support for mlxsw Spectrum-2, from Nir Dotan.
14) Lots of new IP tunneling forwarding tests, also from Nir Dotan.
15) Add 3ad stats to bonding, from Nikolay Aleksandrov.
16) Lots of probing improvements for bpftool, from Quentin Monnet.
17) Various nfp drive #ebpf JIT improvements from Jakub Kicinski.
18) Allow #ebpf programs to access gso_segs from skb shared info, from
Eric Dumazet.
19) Add sock_diag support for AF_XDP sockets, from Björn Töpel.
20) Support 22260 iwlwifi devices, from Luca Coelho.
21) Use rbtree for ipv6 defragmentation, from Peter Oskolkov.
22) Add JMP32 instruction class support to #ebpf, from Jiong Wang.
23) Add spinlock support to #ebpf, from Alexei Starovoitov.
24) Support 256-bit keys and TLS 1.3 in ktls, from Dave Watson.
25) Add device infomation API to devlink, from Jakub Kicinski.
26) Add new timestamping socket options which are y2038 safe, from
Deepa Dinamani.
27) Add RX checksum offloading for various sh_eth chips, from Sergei
Shtylyov.
28) Flow offload infrastructure, from Pablo Neira Ayuso.
29) Numerous cleanups, improvements, and bug fixes to the PHY layer
and many drivers from Heiner Kallweit.
30) Lots of changes to try and make packet scheduler classifiers run
lockless as much as possible, from Vlad Buslov.
31) Support BCM957504 chip in bnxt_en driver, from Erik Burrows.
32) Add concurrency tests to tc-tests infrastructure, from Vlad
Buslov.
33) Add hwmon support to aquantia, from Heiner Kallweit.
34) Allow 64-bit values for SO_MAX_PACING_RATE, from Eric Dumazet.
And I would be remiss if I didn't thank the various major networking
subsystem maintainers for integrating much of this work before I even
saw it. Alexei Starovoitov, Daniel Borkmann, Pablo Neira Ayuso,
Johannes Berg, Kalle Valo, and many others. Thank you!"
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2207 commits)
net/sched: avoid unused-label warning
net: ignore sysctl_devconf_inherit_init_net without SYSCTL
phy: mdio-mux: fix Kconfig dependencies
net: phy: use phy_modify_mmd_changed in genphy_c45_an_config_aneg
net: dsa: mv88e6xxx: add call to mv88e6xxx_ports_cmode_init to probe for new DSA framework
selftest/net: Remove duplicate header
sky2: Disable MSI on Dell Inspiron 1545 and Gateway P-79
net/mlx5e: Update tx reporter status in case channels were successfully opened
devlink: Add support for direct reporter health state update
devlink: Update reporter state to error even if recover aborted
sctp: call iov_iter_revert() after sending ABORT
team: Free BPF filter when unregistering netdev
ip6mr: Do not call __IP6_INC_STATS() from preemptible context
isdn: mISDN: Fix potential NULL pointer dereference of kzalloc
net: dsa: mv88e6xxx: support in-band signalling on SGMII ports with external PHYs
cxgb4/chtls: Prefix adapter flags with CXGB4
net-sysfs: Switch to bitmap_zalloc()
mellanox: Switch to bitmap_zalloc()
bpf: add test cases for non-pointer sanitiation logic
mlxsw: i2c: Extend initialization by querying resources data
...
Add some logging to the core users of the fs_context log so that
information can be extracted from them as to the reason for failure.
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Make the cpuset filesystem use the filesystem context. This is potentially
tricky as the cpuset fs is almost an alias for the cgroup filesystem, but
with some special parameters.
This can, however, be handled by setting up an appropriate cgroup
filesystem and returning the root directory of that as the root dir of this
one.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Make kernfs support superblock creation/mount/remount with fs_context.
This requires that sysfs, cgroup and intel_rdt, which are built on kernfs,
be made to support fs_context also.
Notes:
(1) A kernfs_fs_context struct is created to wrap fs_context and the
kernfs mount parameters are moved in here (or are in fs_context).
(2) kernfs_mount{,_ns}() are made into kernfs_get_tree(). The extra
namespace tag parameter is passed in the context if desired
(3) kernfs_free_fs_context() is provided as a destructor for the
kernfs_fs_context struct, but for the moment it does nothing except
get called in the right places.
(4) sysfs doesn't wrap kernfs_fs_context since it has no parameters to
pass, but possibly this should be done anyway in case someone wants to
add a parameter in future.
(5) A cgroup_fs_context struct is created to wrap kernfs_fs_context and
the cgroup v1 and v2 mount parameters are all moved there.
(6) cgroup1 parameter parsing error messages are now handled by invalf(),
which allows userspace to collect them directly.
(7) cgroup1 parameter cleanup is now done in the context destructor rather
than in the mount/get_tree and remount functions.
Weirdies:
(*) cgroup_do_get_tree() calls cset_cgroup_from_root() with locks held,
but then uses the resulting pointer after dropping the locks. I'm
told this is okay and needs commenting.
(*) The cgroup refcount web. This really needs documenting.
(*) cgroup2 only has one root?
Add a suggestion from Thomas Gleixner in which the RDT enablement code is
placed into its own function.
[folded a leak fix from Andrey Vagin]
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
cc: Tejun Heo <tj@kernel.org>
cc: Li Zefan <lizefan@huawei.com>
cc: Johannes Weiner <hannes@cmpxchg.org>
cc: cgroups@vger.kernel.org
cc: fenghua.yu@intel.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
pass it fs_context instead of fs_type/flags/root triple, have
it return int instead of dentry and make it deal with setting
fc->root.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Note that this reference is *NOT* contributing to refcount of
cgroup_root in question and is valid only until cgroup_do_mount()
returns.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[again, carved out of patch by dhowells]
[NB: we probably want to handle "source" in parse_param here]
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Store the results in cgroup_fs_context. There's a nasty twist caused
by the enabling/disabling subsystems - we can't do the checks sensitive
to that until cgroup_mutex gets grabbed. Frankly, these checks are
complete bullshit (e.g. all,none combination is accepted if all subsystems
are disabled; so's cpusets,none and all,cpusets when cpusets is disabled,
etc.), but touching that would be a userland-visible behaviour change ;-/
So we do parsing in ->parse_monolithic() and have the consistency checks
done in check_cgroupfs_options(), with the latter called (on already parsed
options) from cgroup1_get_tree() and cgroup1_reconfigure().
Freeing the strdup'ed strings is done from fs_context destructor, which
somewhat simplifies the life for cgroup1_{get_tree,reconfigure}().
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Unfortunately, cgroup is tangled into kernfs infrastructure.
To avoid converting all kernfs-based filesystems at once,
we need to untangle the remount part of things, instead of
having it go through kernfs_sop_remount_fs(). Fortunately,
it's not hard to do.
This commit just gets cgroup/cgroup1 to use fs_context to
deliver options on mount and remount paths. Parsing those
is going to be done in the next commits; for now we do
pretty much what legacy case does.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This is a remnant of commit 5f155f27cb ("mm, cpuset: always use
seqlock when changing task's nodemask").
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
cgroup_rstat_cpu_pop_updated() is used to traverse the updated cgroups
on flush. While it was only visiting updated ones in the subtree, it
was visiting @root unconditionally. We can easily check whether @root
is updated or not by looking at its ->updated_next just as with the
cgroups in the subtree.
* Remove the unnecessary cgroup_parent() test. The system root cgroup
is never updated and thus its ->updated_next is always NULL. No
need to test whether cgroup_parent() exists in addition to
->updated_next.
* Terminate traverse if ->updated_next is NULL. This can only happen
for subtree @root and there's no reason to visit it if it's not
marked updated.
This reduces cpu consumption when reading a lot of rstat backed files.
In a micro benchmark reading stat from ~1600 cgroups, the sys time was
lowered by >40%.
Signed-off-by: Tejun Heo <tj@kernel.org>
The only user of cgroup_subsys->free() callback is pids_cgrp_subsys which
needs pids_free() to uncharge the pid.
However, ->free() is called from __put_task_struct()->cgroup_free() and this
is too late. Even the trivial program which does
for (;;) {
int pid = fork();
assert(pid >= 0);
if (pid)
wait(NULL);
else
exit(0);
}
can run out of limits because release_task()->call_rcu(delayed_put_task_struct)
implies an RCU gp after the task/pid goes away and before the final put().
Test-case:
mkdir -p /tmp/CG
mount -t cgroup2 none /tmp/CG
echo '+pids' > /tmp/CG/cgroup.subtree_control
mkdir /tmp/CG/PID
echo 2 > /tmp/CG/PID/pids.max
perl -e 'while ($p = fork) { wait; } $p // die "fork failed: $!\n"' &
echo $! > /tmp/CG/PID/cgroup.procs
Without this patch the forking process fails soon after migration.
Rename cgroup_subsys->free() to cgroup_subsys->release() and move the callsite
into the new helper, cgroup_release(), called by release_task() which actually
frees the pid(s).
Reported-by: Herton R. Krzesinski <hkrzesin@redhat.com>
Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Building with W=1 reveals some bitrot:
CC kernel/bpf/cgroup.o
kernel/bpf/cgroup.c:238: warning: Function parameter or member 'flags' not described in '__cgroup_bpf_attach'
kernel/bpf/cgroup.c:367: warning: Function parameter or member 'unused_flags' not described in '__cgroup_bpf_detach'
Add a kerneldoc line for 'flags'.
Fixing the warning for 'unused_flags' is best approached by
removing the unused parameter on the function call.
Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
RDMA cgroup registration routine always returns success, so simplify
function to be void and run clang formatter over whole CONFIG_CGROUP_RDMA
art of core_priv.h.
This reduces unwinding error path for regular registration and future net
namespace change functionality for rdma device.
Signed-off-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
* make the reference from superblock to cgroup_root counting -
do cgroup_put() in cgroup_kill_sb() whether we'd done
percpu_ref_kill() or not; matching grab is done when we allocate
a new root. That gives the same refcounting rules for all callers
of cgroup_do_mount() - a reference to cgroup_root has been grabbed
by caller and it either is transferred to new superblock or dropped.
* have cgroup_kill_sb() treat an already killed refcount as "just
don't bother killing it, then".
* after successful cgroup_do_mount() have cgroup1_mount() recheck
if we'd raced with mount/umount from somebody else and cgroup_root
got killed. In that case we drop the superblock and bugger off
with -ERESTARTSYS, same as if we'd found it in the list already
dying.
* don't bother with delayed initialization of refcount - it's
unreliable and not needed. No need to prevent attempts to bump
the refcount if we find cgroup_root of another mount in progress -
sget will reuse an existing superblock just fine and if the
other sb manages to die before we get there, we'll catch
that immediately after cgroup_do_mount().
* don't bother with kernfs_pin_sb() - no need for doing that
either.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
same story as with last May fixes in sysfs (7b745a4e40
"unfuck sysfs_mount()"); new_sb is left uninitialized
in case of early errors in kernfs_mount_ns() and papering
over it by treating any error from kernfs_mount_ns() as
equivalent to !new_ns ends up conflating the cases when
objects had never been transferred to a superblock with
ones when that has happened and resulting new superblock
had been dropped. Easily fixed (same way as in sysfs
case). Additionally, there's a superblock leak on
kernfs_node_dentry() failure *and* a dentry leak inside
kernfs_node_dentry() itself - the latter on probably
impossible errors, but the former not impossible to trigger
(as the matter of fact, injecting allocation failures
at that point *does* trigger it).
Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull cgroup updates from Tejun Heo:
- Waiman's cgroup2 cpuset support has been finally merged closing one
of the last remaining feature gaps.
- cgroup.procs could show non-leader threads when cgroup2 threaded mode
was used in certain ways. I forgot to push the fix during the last
cycle.
- A patch to fix mount option parsing when all mount options have been
consumed by someone else (LSM).
- cgroup_no_v1 boot param can now block named cgroup1 hierarchies too.
* 'for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: Add named hierarchy disabling to cgroup_no_v1 boot param
cgroup: fix parsing empty mount option string
cpuset: Remove set but not used variable 'cs'
cgroup: fix CSS_TASK_ITER_PROCS
cgroup: Add .__DEBUG__. prefix to debug file names
cpuset: Minor cgroup2 interface updates
cpuset: Expose cpuset.cpus.subpartitions with cgroup_debug
cpuset: Add documentation about the new "cpuset.sched.partition" flag
cpuset: Use descriptive text when reading/writing cpuset.sched.partition
cpuset: Expose cpus.effective and mems.effective on cgroup v2 root
cpuset: Make generate_sched_domains() work with partition
cpuset: Make CPU hotplug work with partition
cpuset: Track cpusets that use parent's effective_cpus
cpuset: Add an error state to cpuset.sched.partition
cpuset: Add new v2 cpuset.sched.partition flag
cpuset: Simply allocation and freeing of cpumasks
cpuset: Define data structures to support scheduling partition
cpuset: Enable cpuset controller in default hierarchy
cgroup: remove unnecessary unlikely()
