Knowing the number of event entries in the ring buffer compared
to the total number that were written is useful information. The
latency format gives this information and there's no reason that the
default format does not.
This information is now added to the default header, along with the
number of online CPUs:
# tracer: nop
#
# entries-in-buffer/entries-written: 159836/64690869 #P:4
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
<idle>-0 [000] ...2 49.442971: local_touch_nmi <-cpu_idle
<idle>-0 [000] d..2 49.442973: enter_idle <-cpu_idle
<idle>-0 [000] d..2 49.442974: atomic_notifier_call_chain <-enter_idle
<idle>-0 [000] d..2 49.442976: __atomic_notifier_call_chain <-atomic_notifier
The above shows that the trace contains 159836 entries, but
64690869 were written. One could figure out that there were
64531033 entries that were dropped.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
People keep asking how to get the preempt count, irq, and need resched info
and we keep telling them to enable the latency format. Some developers think
that traces without this info is completely useless, and for a lot of tasks
it is useless.
The first option was to enable the latency trace as the default format, but
the header for the latency format is pretty useless for most tracers and
it also does the timestamp in straight microseconds from the time the trace
started. This is sometimes more difficult to read as the default trace is
seconds from the start of boot up.
Latency format:
# tracer: nop
#
# nop latency trace v1.1.5 on 3.2.0-rc1-test+
# --------------------------------------------------------------------
# latency: 0 us, #159771/64234230, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4)
# -----------------
# | task: -0 (uid:0 nice:0 policy:0 rt_prio:0)
# -----------------
#
# _------=> CPU#
# / _-----=> irqs-off
# | / _----=> need-resched
# || / _---=> hardirq/softirq
# ||| / _--=> preempt-depth
# |||| / delay
# cmd pid ||||| time | caller
# \ / ||||| \ | /
migratio-6 0...2 41778231us+: rcu_note_context_switch <-__schedule
migratio-6 0...2 41778233us : trace_rcu_utilization <-rcu_note_context_switch
migratio-6 0...2 41778235us+: rcu_sched_qs <-rcu_note_context_switch
migratio-6 0d..2 41778236us+: rcu_preempt_qs <-rcu_note_context_switch
migratio-6 0...2 41778238us : trace_rcu_utilization <-rcu_note_context_switch
migratio-6 0...2 41778239us+: debug_lockdep_rcu_enabled <-__schedule
default format:
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
migration/0-6 [000] 50.025810: rcu_note_context_switch <-__schedule
migration/0-6 [000] 50.025812: trace_rcu_utilization <-rcu_note_context_switch
migration/0-6 [000] 50.025813: rcu_sched_qs <-rcu_note_context_switch
migration/0-6 [000] 50.025815: rcu_preempt_qs <-rcu_note_context_switch
migration/0-6 [000] 50.025817: trace_rcu_utilization <-rcu_note_context_switch
migration/0-6 [000] 50.025818: debug_lockdep_rcu_enabled <-__schedule
migration/0-6 [000] 50.025820: debug_lockdep_rcu_enabled <-__schedule
The latency format header has latency information that is pretty meaningless
for most tracers. Although some of the header is useful, and we can add that
later to the default format as well.
What is really useful with the latency format is the irqs-off, need-resched
hard/softirq context and the preempt count.
This commit adds the option irq-info which is on by default that adds this
information:
# tracer: nop
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
<idle>-0 [000] d..2 49.309305: cpuidle_get_driver <-cpuidle_idle_call
<idle>-0 [000] d..2 49.309307: mwait_idle <-cpu_idle
<idle>-0 [000] d..2 49.309309: need_resched <-mwait_idle
<idle>-0 [000] d..2 49.309310: test_ti_thread_flag <-need_resched
<idle>-0 [000] d..2 49.309312: trace_power_start.constprop.13 <-mwait_idle
<idle>-0 [000] d..2 49.309313: trace_cpu_idle <-mwait_idle
<idle>-0 [000] d..2 49.309315: need_resched <-mwait_idle
If a user wants the old format, they can disable the 'irq-info' option:
# tracer: nop
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
<idle>-0 [000] 49.309305: cpuidle_get_driver <-cpuidle_idle_call
<idle>-0 [000] 49.309307: mwait_idle <-cpu_idle
<idle>-0 [000] 49.309309: need_resched <-mwait_idle
<idle>-0 [000] 49.309310: test_ti_thread_flag <-need_resched
<idle>-0 [000] 49.309312: trace_power_start.constprop.13 <-mwait_idle
<idle>-0 [000] 49.309313: trace_cpu_idle <-mwait_idle
<idle>-0 [000] 49.309315: need_resched <-mwait_idle
Requested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This patch solves the following problem:
Now some samples may be lost due to throttling. The number of samples is
restricted by sysctl_perf_event_sample_rate/HZ. A trace event is
divided on some samples according to event's period. I don't sure, that
we should generate more than one sample on each trace event. I think the
better way to use SAMPLE_PERIOD.
E.g.: I want to trace when a process sleeps. I created a process, which
sleeps for 1ms and for 4ms. perf got 100 events in both cases.
swapper 0 [000] 1141.371830: sched_stat_sleep: comm=foo pid=1801 delay=1386750 [ns]
swapper 0 [000] 1141.369444: sched_stat_sleep: comm=foo pid=1801 delay=4499585 [ns]
In the first case a kernel want to send 4499585 events and
in the second case it wants to send 1386750 events.
perf-reports shows that process sleeps in both places equal time. It's
bug.
With this patch kernel generates one event on each "sleep" and the time
slice is saved in the field "period". Perf knows how handle it.
Signed-off-by: Andrew Vagin <avagin@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1320670457-2633428-3-git-send-email-avagin@openvz.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Split the callchain code from the perf events core into
a new kernel/events/callchain.c file.
This simplifies a bit the big core.c
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
[keep ctx recursion handling inline and use internal headers]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1318778104-17152-1-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since commit 4a31a334, the name of this misc device is not initialized,
which leads to a funny device named /dev/(null) being created and
/proc/misc containing an entry with just a number but no name. The latter
leads to complaints by cryptsetup, which caused me to investigate this
matter.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
If the set_ftrace_filter is cleared by writing just whitespace to
it, then the filter hash refcounts will be decremented but not
updated. This causes two bugs:
1) No functions will be enabled for tracing when they all should be
2) If the users clears the set_ftrace_filter twice, it will crash ftrace:
------------[ cut here ]------------
WARNING: at /home/rostedt/work/git/linux-trace.git/kernel/trace/ftrace.c:1384 __ftrace_hash_rec_update.part.27+0x157/0x1a7()
Modules linked in:
Pid: 2330, comm: bash Not tainted 3.1.0-test+ #32
Call Trace:
[<ffffffff81051828>] warn_slowpath_common+0x83/0x9b
[<ffffffff8105185a>] warn_slowpath_null+0x1a/0x1c
[<ffffffff810ba362>] __ftrace_hash_rec_update.part.27+0x157/0x1a7
[<ffffffff810ba6e8>] ? ftrace_regex_release+0xa7/0x10f
[<ffffffff8111bdfe>] ? kfree+0xe5/0x115
[<ffffffff810ba51e>] ftrace_hash_move+0x2e/0x151
[<ffffffff810ba6fb>] ftrace_regex_release+0xba/0x10f
[<ffffffff8112e49a>] fput+0xfd/0x1c2
[<ffffffff8112b54c>] filp_close+0x6d/0x78
[<ffffffff8113a92d>] sys_dup3+0x197/0x1c1
[<ffffffff8113a9a6>] sys_dup2+0x4f/0x54
[<ffffffff8150cac2>] system_call_fastpath+0x16/0x1b
---[ end trace 77a3a7ee73794a02 ]---
Link: http://lkml.kernel.org/r/20111101141420.GA4918@debian
Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
If cpu A calls jump_label_inc() just after atomic_add_return() is
called by cpu B, atomic_inc_not_zero() will return value greater then
zero and jump_label_inc() will return to a caller before jump_label_update()
finishes its job on cpu B.
Link: http://lkml.kernel.org/r/20111018175551.GH17571@redhat.com
Cc: stable@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
A forced undef of a config value was used for testing and was
accidently left in during the final commit. This causes x86 to
run slower than needed while running function tracing as well
as causes the function graph selftest to fail when DYNMAIC_FTRACE
is not set. This is because the code in MCOUNT expects the ftrace
code to be processed with the config value set that happened to
be forced not set.
The forced config option was left in by:
commit 6331c28c96
ftrace: Fix dynamic selftest failure on some archs
Link: http://lkml.kernel.org/r/20111102150255.GA6973@debian
Cc: stable@vger.kernel.org
Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The pretty print of the lockdep debug splat uses just the lock name
to show how the locking scenario happens. But when it comes to
nesting locks, the output becomes confusing which takes away the point
of the pretty printing of the lock scenario.
Without displaying the subclass info, we get the following output:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(slock-AF_INET);
lock(slock-AF_INET);
lock(slock-AF_INET);
lock(slock-AF_INET);
*** DEADLOCK ***
The above looks more of a A->A locking bug than a A->B B->A.
By adding the subclass to the output, we can see what really happened:
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(slock-AF_INET);
lock(slock-AF_INET/1);
lock(slock-AF_INET);
lock(slock-AF_INET/1);
*** DEADLOCK ***
This bug was discovered while tracking down a real bug caught by lockdep.
Link: http://lkml.kernel.org/r/20111025202049.GB25043@hostway.ca
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Simon Kirby <sim@hostway.ca>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* 'upstream/jump-label-noearly' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
jump-label: initialize jump-label subsystem much earlier
x86/jump_label: add arch_jump_label_transform_static()
s390/jump-label: add arch_jump_label_transform_static()
jump_label: add arch_jump_label_transform_static() to optimise non-live code updates
sparc/jump_label: drop arch_jump_label_text_poke_early()
x86/jump_label: drop arch_jump_label_text_poke_early()
jump_label: if a key has already been initialized, don't nop it out
stop_machine: make stop_machine safe and efficient to call early
jump_label: use proper atomic_t initializer
Conflicts:
- arch/x86/kernel/jump_label.c
Added __init_or_module to arch_jump_label_text_poke_early vs
removal of that function entirely
- kernel/stop_machine.c
same patch ("stop_machine: make stop_machine safe and efficient
to call early") merged twice, with whitespace fix in one version
* 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: (230 commits)
Revert "tracing: Include module.h in define_trace.h"
irq: don't put module.h into irq.h for tracking irqgen modules.
bluetooth: macroize two small inlines to avoid module.h
ip_vs.h: fix implicit use of module_get/module_put from module.h
nf_conntrack.h: fix up fallout from implicit moduleparam.h presence
include: replace linux/module.h with "struct module" wherever possible
include: convert various register fcns to macros to avoid include chaining
crypto.h: remove unused crypto_tfm_alg_modname() inline
uwb.h: fix implicit use of asm/page.h for PAGE_SIZE
pm_runtime.h: explicitly requires notifier.h
linux/dmaengine.h: fix implicit use of bitmap.h and asm/page.h
miscdevice.h: fix up implicit use of lists and types
stop_machine.h: fix implicit use of smp.h for smp_processor_id
of: fix implicit use of errno.h in include/linux/of.h
of_platform.h: delete needless include <linux/module.h>
acpi: remove module.h include from platform/aclinux.h
miscdevice.h: delete unnecessary inclusion of module.h
device_cgroup.h: delete needless include <linux/module.h>
net: sch_generic remove redundant use of <linux/module.h>
net: inet_timewait_sock doesnt need <linux/module.h>
...
Fix up trivial conflicts (other header files, and removal of the ab3550 mfd driver) in
- drivers/media/dvb/frontends/dibx000_common.c
- drivers/media/video/{mt9m111.c,ov6650.c}
- drivers/mfd/ab3550-core.c
- include/linux/dmaengine.h
* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Add a 'reason' to wb_writeback_work
writeback: send work item to queue_io, move_expired_inodes
writeback: trace event balance_dirty_pages
writeback: trace event bdi_dirty_ratelimit
writeback: fix ppc compile warnings on do_div(long long, unsigned long)
writeback: per-bdi background threshold
writeback: dirty position control - bdi reserve area
writeback: control dirty pause time
writeback: limit max dirty pause time
writeback: IO-less balance_dirty_pages()
writeback: per task dirty rate limit
writeback: stabilize bdi->dirty_ratelimit
writeback: dirty rate control
writeback: add bg_threshold parameter to __bdi_update_bandwidth()
writeback: dirty position control
writeback: account per-bdi accumulated dirtied pages
* git://github.com/rustyrussell/linux:
module,bug: Add TAINT_OOT_MODULE flag for modules not built in-tree
module: Enable dynamic debugging regardless of taint
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (106 commits)
powerpc/p3060qds: Add support for P3060QDS board
powerpc/83xx: Add shutdown request support to MCU handling on MPC8349 MITX
powerpc/85xx: Make kexec to interate over online cpus
powerpc/fsl_booke: Fix comment in head_fsl_booke.S
powerpc/85xx: issue 15 EOI after core reset for FSL CoreNet devices
powerpc/8xxx: Fix interrupt handling in MPC8xxx GPIO driver
powerpc/85xx: Add 'fsl,pq3-gpio' compatiable for GPIO driver
powerpc/86xx: Correct Gianfar support for GE boards
powerpc/cpm: Clear muram before it is in use.
drivers/virt: add ioctl for 32-bit compat on 64-bit to fsl-hv-manager
powerpc/fsl_msi: add support for "msi-address-64" property
powerpc/85xx: Setup secondary cores PIR with hard SMP id
powerpc/fsl-booke: Fix settlbcam for 64-bit
powerpc/85xx: Adding DCSR node to dtsi device trees
powerpc/85xx: clean up FPGA device tree nodes for Freecsale QorIQ boards
powerpc/85xx: fix PHYS_64BIT selection for P1022DS
powerpc/fsl-booke: Fix setup_initial_memory_limit to not blindly map
powerpc: respect mem= setting for early memory limit setup
powerpc: Update corenet64_smp_defconfig
powerpc: Update mpc85xx/corenet 32-bit defconfigs
...
Fix up trivial conflicts in:
- arch/powerpc/configs/40x/hcu4_defconfig
removed stale file, edited elsewhere
- arch/powerpc/include/asm/udbg.h, arch/powerpc/kernel/udbg.c:
added opal and gelic drivers vs added ePAPR driver
- drivers/tty/serial/8250.c
moved UPIO_TSI to powerpc vs removed UPIO_DWAPB support
Use of the GPL or a compatible licence doesn't necessarily make the code
any good. We already consider staging modules to be suspect, and this
should also be true for out-of-tree modules which may receive very
little review.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Reviewed-by: Dave Jones <davej@redhat.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (patched oops-tracing.txt)
Dynamic debugging is currently disabled for tainted modules, except
for TAINT_CRAP. This prevents use of dynamic debugging for
out-of-tree modules once the next patch is applied.
This condition was apparently intended to avoid a crash if a force-
loaded module has an incompatible definition of dynamic debug
structures. However, a administrator that forces us to load a module
is claiming that it *is* compatible even though it fails our version
checks. If they are mistaken, there are any number of ways the module
could crash the system.
As a side-effect, proprietary and other tainted modules can now use
dynamic_debug.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The system filter can be used to set multiple event filters that
exist within the system. But currently it displays the last filter
written that does not necessarily correspond to the filters within
the system. The system filter itself is not used to filter any events.
The system filter is just a means to set filters of the events within
it.
Because this causes an ambiguous state when the system filter reads
a filter string but the events within the system have different strings
it is best to just show a boiler plate:
### global filter ###
# Use this to set filters for multiple events.
# Only events with the given fields will be affected.
# If no events are modified, an error message will be displayed here.
If an error occurs while writing to the system filter, the system
filter will replace the boiler plate with the error message as it
currently does.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Commit 27920651fe "PM / Freezer: Make fake_signal_wake_up() wake
TASK_KILLABLE tasks too" updated fake_signal_wake_up() used by freezer
to wake up KILLABLE tasks. Sending unsolicited wakeups to tasks in
killable sleep is dangerous as there are code paths which depend on
tasks not waking up spuriously from KILLABLE sleep.
For example. sys_read() or page can sleep in TASK_KILLABLE assuming
that wait/down/whatever _killable can only fail if we can not return
to the usermode. TASK_TRACED is another obvious example.
The previous patch updated wait_event_freezekillable() such that it
doesn't depend on the spurious wakeup. This patch reverts the
offending commit.
Note that the spurious KILLABLE wakeup had other implicit effects in
KILLABLE sleeps in nfs and cifs and those will need further updates to
regain freezekillable behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Remove an "if" check, that repeats an equivalent one 6 lines above.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
The CPU hotplug notifications sent out by the _cpu_up() and _cpu_down()
functions depend on the value of the 'tasks_frozen' argument passed to them
(which indicates whether tasks have been frozen or not).
(Examples for such CPU hotplug notifications: CPU_ONLINE, CPU_ONLINE_FROZEN,
CPU_DEAD, CPU_DEAD_FROZEN).
Thus, it is essential that while the callbacks for those notifications are
running, the state of the system with respect to the tasks being frozen or
not remains unchanged, *throughout that duration*. Hence there is a need for
synchronizing the CPU hotplug code with the freezer subsystem.
Since the freezer is involved only in the Suspend/Hibernate call paths, this
patch hooks the CPU hotplug code to the suspend/hibernate notifiers
PM_[SUSPEND|HIBERNATE]_PREPARE and PM_POST_[SUSPEND|HIBERNATE] to prevent
the race between CPU hotplug and freezer, thus ensuring that CPU hotplug
notifications will always be run with the state of the system really being
what the notifications indicate, _throughout_ their execution time.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
This reverts commit 144060fee0.
It causes a resume regression for Andi on his Acer Aspire 1830T post
3.1. The screen just stays black after wakeup.
Also, it really looks like the wrong way to suspend and resume perf
events: I think they should be done as part of the CPU suspend and
resume, rather than as a notifier that does smp_call_function().
Reported-by: Andi Kleen <andi@firstfloor.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While back-porting Johannes Weiner's patch "mm: memcg-aware global
reclaim" for an internal effort, we noticed a significant performance
regression during page-reclaim heavy workloads due to high contention of
the ss->id_lock. This lock protects idr map, and serializes calls to
idr_get_next() in css_get_next() (which is used during the memcg hierarchy
walk).
Since idr_get_next() is just doing a look up, we need only serialize it
with respect to idr_remove()/idr_get_new(). By making the ss->id_lock a
rwlock, contention is greatly reduced and performance improves.
Tested: cat a 256m file from a ramdisk in a 128m container 50 times on
each core (one file + container per core) in parallel on a NUMA machine.
Result is the time for the test to complete in 1 of the containers.
Both kernels included Johannes' memcg-aware global reclaim patches.
Before rwlock patch: 1710.778s
After rwlock patch: 152.227s
Signed-off-by: Andrew Bresticker <abrestic@google.com>
Cc: Paul Menage <menage@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Adding support for poll() in sysctl fs allows userspace to receive
notifications of changes in sysctl entries. This adds a infrastructure to
allow files in sysctl fs to be pollable and implements it for hostname and
domainname.
[akpm@linux-foundation.org: s/declare/define/ for definitions]
Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: Greg KH <gregkh@suse.de>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
{get,put}_mems_allowed() exist so that general kernel code may locklessly
access a task's set of allowable nodes without having the chance that a
concurrent write will cause the nodemask to be empty on configurations
where MAX_NUMNODES > BITS_PER_LONG.
This could incur a significant delay, however, especially in low memory
conditions because the page allocator is blocking and reclaim requires
get_mems_allowed() itself. It is not atypical to see writes to
cpuset.mems take over 2 seconds to complete, for example. In low memory
conditions, this is problematic because it's one of the most imporant
times to change cpuset.mems in the first place!
The only way a task's set of allowable nodes may change is through cpusets
by writing to cpuset.mems and when attaching a task to a generic code is
not reading the nodemask with get_mems_allowed() at the same time, and
then clearing all the old nodes. This prevents the possibility that a
reader will see an empty nodemask at the same time the writer is storing a
new nodemask.
If at least one node remains unchanged, though, it's possible to simply
set all new nodes and then clear all the old nodes. Changing a task's
nodemask is protected by cgroup_mutex so it's guaranteed that two threads
are not changing the same task's nodemask at the same time, so the
nodemask is guaranteed to be stored before another thread changes it and
determines whether a node remains set or not.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Paul Menage <paul@paulmenage.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a task has exited to the point it has called cgroup_exit() already,
then we can't migrate it to another cgroup anymore.
This can happen when we are attaching a task to a new cgroup between the
call to ->can_attach_task() on subsystems and the migration that is
eventually tried in cgroup_task_migrate().
In this case cgroup_task_migrate() returns -ESRCH and we don't want to
attach the task to the subsystems because the attachment to the new cgroup
itself failed.
Fix this by only calling ->attach_task() on the subsystems if the cgroup
migration succeeded.
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix unstable tasklist locking in cgroup_attach_proc.
According to this thread - https://lkml.org/lkml/2011/7/27/243 - RCU is
not sufficient to guarantee the tasklist is stable w.r.t. de_thread and
exit. Taking tasklist_lock for reading, instead of rcu_read_lock, ensures
proper exclusion.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Though not all events have field 'prev_pid', it was allowed to do this:
# echo 'prev_pid == 100' > events/sched/filter
but commit 75b8e98263 (tracing/filter: Swap
entire filter of events) broke it without any reason.
Link: http://lkml.kernel.org/r/4EAF46CF.8040408@cn.fujitsu.com
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* 'next/dt' of git://git.linaro.org/people/arnd/arm-soc:
ARM: gic: use module.h instead of export.h
ARM: gic: fix irq_alloc_descs handling for sparse irq
ARM: gic: add OF based initialization
ARM: gic: add irq_domain support
irq: support domains with non-zero hwirq base
of/irq: introduce of_irq_init
ARM: at91: add at91sam9g20 and Calao USB A9G20 DT support
ARM: at91: dt: at91sam9g45 family and board device tree files
arm/mx5: add device tree support for imx51 babbage
arm/mx5: add device tree support for imx53 boards
ARM: msm: Add devicetree support for msm8660-surf
msm_serial: Add devicetree support
msm_serial: Use relative resources for iomem
Fix up conflicts in arch/arm/mach-at91/{at91sam9260.c,at91sam9g45.c}
Quoth Andrew:
- Most of MM. Still waiting for the poweroc guys to get off their
butts and review some threaded hugepages patches.
- alpha
- vfs bits
- drivers/misc
- a few core kerenl tweaks
- printk() features
- MAINTAINERS updates
- backlight merge
- leds merge
- various lib/ updates
- checkpatch updates
* akpm: (127 commits)
epoll: fix spurious lockdep warnings
checkpatch: add a --strict check for utf-8 in commit logs
kernel.h/checkpatch: mark strict_strto<foo> and simple_strto<foo> as obsolete
llist-return-whether-list-is-empty-before-adding-in-llist_add-fix
wireless: at76c50x: follow rename pack_hex_byte to hex_byte_pack
fat: follow rename pack_hex_byte() to hex_byte_pack()
security: follow rename pack_hex_byte() to hex_byte_pack()
kgdb: follow rename pack_hex_byte() to hex_byte_pack()
lib: rename pack_hex_byte() to hex_byte_pack()
lib/string.c: fix strim() semantics for strings that have only blanks
lib/idr.c: fix comment for ida_get_new_above()
lib/percpu_counter.c: enclose hotplug only variables in hotplug ifdef
lib/bitmap.c: quiet sparse noise about address space
lib/spinlock_debug.c: print owner on spinlock lockup
lib/kstrtox: common code between kstrto*() and simple_strto*() functions
drivers/leds/leds-lp5521.c: check if reset is successful
leds: turn the blink_timer off before starting to blink
leds: save the delay values after a successful call to blink_set()
drivers/leds/leds-gpio.c: use gpio_get_value_cansleep() when initializing
drivers/leds/leds-lm3530.c: add __devexit_p where needed
...
There is no functional change.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently log_prefix is testing that the first character of the log level
and facility is less than '0' and greater than '9' (which is always
false).
Since the code being updated works because strtoul bombs out (endp isn't
updated) and 0 is returned anyway just remove the check and don't change
the behavior of the function.
Signed-off-by: William Douglas <william.douglas@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently log_prefix is testing that the first character of the log level
and facility is less than '0' and greater than '9' (which is always
false). It should be testing to see if the character less than '0' or
greater than '9' instead. This patch makes that change.
The code being changed worked because strtoul bombs out (endp isn't
updated) and 0 is returned anyway.
Signed-off-by: William Douglas <william.douglas@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are enabling some power features on medfield. To test suspend-2-RAM
conveniently, we need turn on/off console_suspend_enabled frequently.
Add a module parameter, so users could change it by:
/sys/module/printk/parameters/console_suspend
Signed-off-by: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We are enabling some power features on medfield. To test suspend-2-RAM
conveniently, we need turn on/off ignore_loglevel frequently without
rebooting.
Add a module parameter, so users can change it by:
/sys/module/printk/parameters/ignore_loglevel
Signed-off-by: Yanmin Zhang <yanmin.zhang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Userspace needs to know the highest valid capability of the running
kernel, which right now cannot reliably be retrieved from the header files
only. The fact that this value cannot be determined properly right now
creates various problems for libraries compiled on newer header files
which are run on older kernels. They assume capabilities are available
which actually aren't. libcap-ng is one example. And we ran into the
same problem with systemd too.
Now the capability is exported in /proc/sys/kernel/cap_last_cap.
[akpm@linux-foundation.org: make cap_last_cap const, per Ulrich]
Signed-off-by: Dan Ballard <dan@mindstab.net>
Cc: Randy Dunlap <rdunlap@xenotime.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Lennart Poettering <lennart@poettering.net>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Ulrich Drepper <drepper@akkadia.org>
Cc: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix compilation warnings for CONFIG_SYSCTL=n:
fixed compilation warnings in case of disabled CONFIG_SYSCTL
kernel/watchdog.c:483:13: warning: `watchdog_enable_all_cpus' defined but not used
kernel/watchdog.c:500:13: warning: `watchdog_disable_all_cpus' defined but not used
these functions are static and are used only in sysctl handler, so move
them inside #ifdef CONFIG_SYSCTL too
Signed-off-by: Vasily Averin <vvs@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Make stop_machine() safe to call early in boot, before SMP has been set
up, by simply calling the callback function directly if there's only one
CPU online.
[ Fixes from AKPM:
- add comment
- local_irq_flags, not save_flags
- also call hard_irq_disable() for systems which need it
Tejun suggested using an explicit flag rather than just looking at
the online cpu count. ]
Cc: Tejun Heo <tj@kernel.org>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: H. Peter Anvin <hpa@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Tejun Heo <htejun@gmail.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some kernel components pin user space memory (infiniband and perf) (by
increasing the page count) and account that memory as "mlocked".
The difference between mlocking and pinning is:
A. mlocked pages are marked with PG_mlocked and are exempt from
swapping. Page migration may move them around though.
They are kept on a special LRU list.
B. Pinned pages cannot be moved because something needs to
directly access physical memory. They may not be on any
LRU list.
I recently saw an mlockalled process where mm->locked_vm became
bigger than the virtual size of the process (!) because some
memory was accounted for twice:
Once when the page was mlocked and once when the Infiniband
layer increased the refcount because it needt to pin the RDMA
memory.
This patch introduces a separate counter for pinned pages and
accounts them seperately.
Signed-off-by: Christoph Lameter <cl@linux.com>
Cc: Mike Marciniszyn <infinipath@qlogic.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This removes mm->oom_disable_count entirely since it's unnecessary and
currently buggy. The counter was intended to be per-process but it's
currently decremented in the exit path for each thread that exits, causing
it to underflow.
The count was originally intended to prevent oom killing threads that
share memory with threads that cannot be killed since it doesn't lead to
future memory freeing. The counter could be fixed to represent all
threads sharing the same mm, but it's better to remove the count since:
- it is possible that the OOM_DISABLE thread sharing memory with the
victim is waiting on that thread to exit and will actually cause
future memory freeing, and
- there is no guarantee that a thread is disabled from oom killing just
because another thread sharing its mm is oom disabled.
Signed-off-by: David Rientjes <rientjes@google.com>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ying Han <yinghan@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The basic idea behind cross memory attach is to allow MPI programs doing
intra-node communication to do a single copy of the message rather than a
double copy of the message via shared memory.
The following patch attempts to achieve this by allowing a destination
process, given an address and size from a source process, to copy memory
directly from the source process into its own address space via a system
call. There is also a symmetrical ability to copy from the current
process's address space into a destination process's address space.
- Use of /proc/pid/mem has been considered, but there are issues with
using it:
- Does not allow for specifying iovecs for both src and dest, assuming
preadv or pwritev was implemented either the area read from or
written to would need to be contiguous.
- Currently mem_read allows only processes who are currently
ptrace'ing the target and are still able to ptrace the target to read
from the target. This check could possibly be moved to the open call,
but its not clear exactly what race this restriction is stopping
(reason appears to have been lost)
- Having to send the fd of /proc/self/mem via SCM_RIGHTS on unix
domain socket is a bit ugly from a userspace point of view,
especially when you may have hundreds if not (eventually) thousands
of processes that all need to do this with each other
- Doesn't allow for some future use of the interface we would like to
consider adding in the future (see below)
- Interestingly reading from /proc/pid/mem currently actually
involves two copies! (But this could be fixed pretty easily)
As mentioned previously use of vmsplice instead was considered, but has
problems. Since you need the reader and writer working co-operatively if
the pipe is not drained then you block. Which requires some wrapping to
do non blocking on the send side or polling on the receive. In all to all
communication it requires ordering otherwise you can deadlock. And in the
example of many MPI tasks writing to one MPI task vmsplice serialises the
copying.
There are some cases of MPI collectives where even a single copy interface
does not get us the performance gain we could. For example in an
MPI_Reduce rather than copy the data from the source we would like to
instead use it directly in a mathops (say the reduce is doing a sum) as
this would save us doing a copy. We don't need to keep a copy of the data
from the source. I haven't implemented this, but I think this interface
could in the future do all this through the use of the flags - eg could
specify the math operation and type and the kernel rather than just
copying the data would apply the specified operation between the source
and destination and store it in the destination.
Although we don't have a "second user" of the interface (though I've had
some nibbles from people who may be interested in using it for intra
process messaging which is not MPI). This interface is something which
hardware vendors are already doing for their custom drivers to implement
fast local communication. And so in addition to this being useful for
OpenMPI it would mean the driver maintainers don't have to fix things up
when the mm changes.
There was some discussion about how much faster a true zero copy would
go. Here's a link back to the email with some testing I did on that:
http://marc.info/?l=linux-mm&m=130105930902915&w=2
There is a basic man page for the proposed interface here:
http://ozlabs.org/~cyeoh/cma/process_vm_readv.txt
This has been implemented for x86 and powerpc, other architecture should
mainly (I think) just need to add syscall numbers for the process_vm_readv
and process_vm_writev. There are 32 bit compatibility versions for
64-bit kernels.
For arch maintainers there are some simple tests to be able to quickly
verify that the syscalls are working correctly here:
http://ozlabs.org/~cyeoh/cma/cma-test-20110718.tgz
Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Howells <dhowells@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: <linux-man@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Recent commit "irq: Track the owner of irq descriptor" in
commit ID b6873807a7 placed module.h into linux/irq.h
but we are trying to limit module.h inclusion to just C files
that really need it, due to its size and number of children
includes. This targets just reversing that include.
Add in the basic "struct module" since that is all we really need
to ensure things compile. In theory, b687380 should have added the
module.h include to the irqdesc.h header as well, but the implicit
module.h everywhere presence masked this from showing up. So give
it the "struct module" as well.
As for the C files, irqdesc.c is only using THIS_MODULE, so it
does not need module.h - give it export.h instead. The C file
irq/manage.c is now (as of b687380) using try_module_get and
module_put and so it needs module.h (which it already has).
Also convert the irq_alloc_descs variants to macros, since all
they really do is is call the __irq_alloc_descs primitive.
This avoids including export.h and no debug info is lost.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
These files were getting <linux/module.h> via an implicit non-obvious
path, but we want to crush those out of existence since they cost
time during compiles of processing thousands of lines of headers
for no reason. Give them the lightweight header that just contains
the EXPORT_SYMBOL infrastructure.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Fix a bug introduced by e9dbfae5, which prevents event_subsystem from
ever being released.
Ref_count was added to keep track of subsystem users, not for counting
events. Subsystem is created with ref_count = 1, so there is no need to
increment it for every event, we have nr_events for that. Fix this by
touching ref_count only when we actually have a new user -
subsystem_open().
Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Link: http://lkml.kernel.org/r/1320052062-7846-1-git-send-email-idryomov@gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
The file rcutiny.c does not need moduleparam.h header, as
there are no modparams in this file.
However rcutiny_plugin.h does define a module_init() and
a module_exit() and it uses the various MODULE_ macros, so
it really does need module.h included.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Through various other implicit include paths, some files were
getting the full module.h file, and hence living the illusion
that they really only needed moduleparam.h -- but the reality
is that once you remove the module.h presence, these show up:
kernel/params.c:583: warning: ‘struct module_kobject’ declared inside parameter list
Such files really require module.h so simply make it so. As the
file module.h grabs moduleparam.h on the fly, all will be well.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
With the module.h usage cleanup, we'll get this:
kernel/ksysfs.c:161: error: ‘S_IRUGO’ undeclared here (not in a function)
make[2]: *** [kernel/ksysfs.o] Error 1
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Up until now, this file was getting percpu.h because nearly every
file was implicitly getting module.h (and all its sub-includes).
But we want to clean that up, so call out percpu.h explicitly.
Otherwise we'll get things like this on an ARM build:
kernel/irq_work.c:48: error: expected declaration specifiers or '...' before 'irq_work_list'
kernel/irq_work.c:48: warning: type defaults to 'int' in declaration of 'DEFINE_PER_CPU'
The same thing was happening for builds on ARM for asm/processor.h
kernel/irq_work.c: In function 'irq_work_sync':
kernel/irq_work.c:166: error: implicit declaration of function 'cpu_relax'
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
These files were implicitly relying on <linux/kmod.h> coming in via
module.h, as without it we get things like:
kernel/power/suspend.c💯 error: implicit declaration of function ‘usermodehelper_disable’
kernel/power/suspend.c:109: error: implicit declaration of function ‘usermodehelper_enable’
kernel/power/user.c:254: error: implicit declaration of function ‘usermodehelper_disable’
kernel/power/user.c:261: error: implicit declaration of function ‘usermodehelper_enable’
kernel/sys.c:317: error: implicit declaration of function ‘usermodehelper_disable’
kernel/sys.c:1816: error: implicit declaration of function ‘call_usermodehelper_setup’
kernel/sys.c:1822: error: implicit declaration of function ‘call_usermodehelper_setfns’
kernel/sys.c:1824: error: implicit declaration of function ‘call_usermodehelper_exec’
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
