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Pick up the latest fixes before applying new changes.
Signed-off-by: Ingo Molnar <[email protected]>
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In futex_wake() there is clearly no point in taking the hb->lock
if we know beforehand that there are no tasks to be woken. While
the hash bucket's plist head is a cheap way of knowing this, we
cannot rely 100% on it as there is a racy window between the
futex_wait call and when the task is actually added to the
plist. To this end, we couple it with the spinlock check as
tasks trying to enter the critical region are most likely
potential waiters that will be added to the plist, thus
preventing tasks sleeping forever if wakers don't acknowledge
all possible waiters.
Furthermore, the futex ordering guarantees are preserved,
ensuring that waiters either observe the changed user space
value before blocking or is woken by a concurrent waker. For
wakers, this is done by relying on the barriers in
get_futex_key_refs() -- for archs that do not have implicit mb
in atomic_inc(), we explicitly add them through a new
futex_get_mm function. For waiters we rely on the fact that
spin_lock calls already update the head counter, so spinners
are visible even if the lock hasn't been acquired yet.
For more details please refer to the updated comments in the
code and related discussion:
https://lkml.org/lkml/2013/11/26/556
Special thanks to tglx for careful review and feedback.
Suggested-by: Linus Torvalds <[email protected]>
Reviewed-by: Darren Hart <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Reviewed-by: Peter Zijlstra <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Jeff Mahoney <[email protected]>
Cc: Scott Norton <[email protected]>
Cc: Tom Vaden <[email protected]>
Cc: Aswin Chandramouleeswaran <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Jason Low <[email protected]>
Cc: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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That's essential, if you want to hack on futexes.
Reviewed-by: Darren Hart <[email protected]>
Reviewed-by: Peter Zijlstra <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Jeff Mahoney <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Scott Norton <[email protected]>
Cc: Tom Vaden <[email protected]>
Cc: Aswin Chandramouleeswaran <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Jason Low <[email protected]>
Cc: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Currently, the futex global hash table suffers from its fixed,
smallish (for today's standards) size of 256 entries, as well as
its lack of NUMA awareness. Large systems, using many futexes,
can be prone to high amounts of collisions; where these futexes
hash to the same bucket and lead to extra contention on the same
hb->lock. Furthermore, cacheline bouncing is a reality when we
have multiple hb->locks residing on the same cacheline and
different futexes hash to adjacent buckets.
This patch keeps the current static size of 16 entries for small
systems, or otherwise, 256 * ncpus (or larger as we need to
round the number to a power of 2). Note that this number of CPUs
accounts for all CPUs that can ever be available in the system,
taking into consideration things like hotpluging. While we do
impose extra overhead at bootup by making the hash table larger,
this is a one time thing, and does not shadow the benefits of
this patch.
Furthermore, as suggested by tglx, by cache aligning the hash
buckets we can avoid access across cacheline boundaries and also
avoid massive cache line bouncing if multiple cpus are hammering
away at different hash buckets which happen to reside in the
same cache line.
Also, similar to other core kernel components (pid, dcache,
tcp), by using alloc_large_system_hash() we benefit from its
NUMA awareness and thus the table is distributed among the nodes
instead of in a single one.
For a custom microbenchmark that pounds on the uaddr hashing --
making the wait path fail at futex_wait_setup() returning
-EWOULDBLOCK for large amounts of futexes, we can see the
following benefits on a 80-core, 8-socket 1Tb server:
+---------+--------------------+------------------------+-----------------------+-------------------------------+
| threads | baseline (ops/sec) | aligned-only (ops/sec) | large table (ops/sec) | large table+aligned (ops/sec) |
+---------+--------------------+------------------------+-----------------------+-------------------------------+
| 512 | 32426 | 50531 (+55.8%) | 255274 (+687.2%) | 292553 (+802.2%) |
| 256 | 65360 | 99588 (+52.3%) | 443563 (+578.6%) | 508088 (+677.3%) |
| 128 | 125635 | 200075 (+59.2%) | 742613 (+491.1%) | 835452 (+564.9%) |
| 80 | 193559 | 323425 (+67.1%) | 1028147 (+431.1%) | 1130304 (+483.9%) |
| 64 | 247667 | 443740 (+79.1%) | 997300 (+302.6%) | 1145494 (+362.5%) |
| 32 | 628412 | 721401 (+14.7%) | 965996 (+53.7%) | 1122115 (+78.5%) |
+---------+--------------------+------------------------+-----------------------+-------------------------------+
Reviewed-by: Darren Hart <[email protected]>
Reviewed-by: Peter Zijlstra <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Reviewed-by: Waiman Long <[email protected]>
Reviewed-and-tested-by: Jason Low <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Jeff Mahoney <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Scott Norton <[email protected]>
Cc: Tom Vaden <[email protected]>
Cc: Aswin Chandramouleeswaran <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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- Remove unnecessary head variables.
- Delete unused parameter in queue_unlock().
Reviewed-by: Darren Hart <[email protected]>
Reviewed-by: Peter Zijlstra <[email protected]>
Reviewed-by: Paul E. McKenney <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Jason Low <[email protected]>
Signed-off-by: Davidlohr Bueso <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Jeff Mahoney <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Scott Norton <[email protected]>
Cc: Tom Vaden <[email protected]>
Cc: Aswin Chandramouleeswaran <[email protected]>
Cc: Waiman Long <[email protected]>
Cc: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Refresh the tree with the latest fixes, before applying new changes.
Signed-off-by: Ingo Molnar <[email protected]>
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git://git.linaro.org/people/john.stultz/linux into timers/core
Pull timekeeping updates from John Stultz.
Signed-off-by: Ingo Molnar <[email protected]>
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Pick up the latest fixes and refresh the branch.
Signed-off-by: Ingo Molnar <[email protected]>
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Unlike recent modern userspace API such as:
epoll_create1 (EPOLL_CLOEXEC), eventfd (EFD_CLOEXEC),
fanotify_init (FAN_CLOEXEC), inotify_init1 (IN_CLOEXEC),
signalfd (SFD_CLOEXEC), timerfd_create (TFD_CLOEXEC),
or the venerable general purpose open (O_CLOEXEC),
perf_event_open() syscall lack a flag to atomically set FD_CLOEXEC
(eg. close-on-exec) flag on file descriptor it returns to userspace.
The present patch adds a PERF_FLAG_FD_CLOEXEC flag to allow
perf_event_open() syscall to atomically set close-on-exec.
Having this flag will enable userspace to remove the file descriptor
from the list of file descriptors being inherited across exec,
without the need to call fcntl(fd, F_SETFD, FD_CLOEXEC) and the
associated race condition between the current thread and another
thread calling fork(2) then execve(2).
Links:
- Secure File Descriptor Handling (Ulrich Drepper, 2008)
http://udrepper.livejournal.com/20407.html
- Excuse me son, but your code is leaking !!! (Dan Walsh, March 2012)
http://danwalsh.livejournal.com/53603.html
- Notes in DMA buffer sharing: leak and security hole
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/dma-buf-sharing.txt?id=v3.13-rc3#n428
Signed-off-by: Yann Droneaud <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Linus Torvalds <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.com
Signed-off-by: Ingo Molnar <[email protected]>
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This patch fixes a problem with the initialization of the
struct perf_event active_entry field. It is defined inside
an anonymous union and was initialized in perf_event_alloc()
using INIT_LIST_HEAD(). However at that time, we do not know
whether the event is going to use active_entry or hlist_entry (SW).
Or at last, we don't want to make that determination there.
The problem is that hlist and list_head are not initialized
the same way. One is okay with NULL (from kzmalloc), the other
needs to pointers to point to self.
This patch resolves this problem by dropping the union.
This will avoid problems later on, if someone starts using
active_entry or hlist_entry without verifying that they
actually overlap. This also solves the initialization
problem.
Signed-off-by: Stephane Eranian <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Unfortunately the seqlock lockdep enablement can't be used
in sched_clock(), since the lockdep infrastructure eventually
calls into sched_clock(), which causes a deadlock.
Thus, this patch changes all generic sched_clock() usage
to use the raw_* methods.
Acked-by: Linus Torvalds <[email protected]>
Reviewed-by: Stephen Boyd <[email protected]>
Reported-by: Krzysztof Hałasa <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Cc: Uwe Kleine-König <[email protected]>
Cc: Willy Tarreau <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Thomas Hellstrom bisected a regression where erratic 3D performance is
experienced on virtual machines as measured by glxgears. It identified
commit 58d081b5 ("sched/numa: Avoid overloading CPUs on a preferred NUMA
node") as the problem which had modified the behaviour of effective_load.
Effective load calculates the difference to the system-wide load if a
scheduling entity was moved to another CPU. The task group is not heavier
as a result of the move but overall system load can increase/decrease as a
result of the change. Commit 58d081b5 ("sched/numa: Avoid overloading CPUs
on a preferred NUMA node") changed effective_load to make it suitable for
calculating if a particular NUMA node was compute overloaded. To reduce
the cost of the function, it assumed that a current sched entity weight
of 0 was uninteresting but that is not the case.
wake_affine() uses a weight of 0 for sync wakeups on the grounds that it
is assuming the waking task will sleep and not contribute to load in the
near future. In this case, we still want to calculate the effective load
of the sched entity hierarchy. As effective_load is no longer used by
task_numa_compare since commit fb13c7ee (sched/numa: Use a system-wide
search to find swap/migration candidates), this patch simply restores the
historical behaviour.
Reported-and-tested-by: Thomas Hellstrom <[email protected]>
Signed-off-by: Rik van Riel <[email protected]>
[ Wrote changelog]
Signed-off-by: Mel Gorman <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI and power management fixes and new device IDs from Rafael Wysocki:
- Fix for a cpufreq regression causing stale sysfs files to be left
behind during system resume if cpufreq_add_dev() fails for one or
more CPUs from Viresh Kumar.
- Fix for a bug in cpufreq causing CONFIG_CPU_FREQ_DEFAULT_* to be
ignored when the intel_pstate driver is used from Jason Baron.
- System suspend fix for a memory leak in pm_vt_switch_unregister()
that forgot to release objects after removing them from
pm_vt_switch_list. From Masami Ichikawa.
- Intel Valley View device ID and energy unit encoding update for the
(recently added) Intel RAPL (Running Average Power Limit) driver from
Jacob Pan.
- Intel Bay Trail SoC GPIO and ACPI device IDs for the Low Power
Subsystem (LPSS) ACPI driver from Paul Drews.
* tag 'pm+acpi-3.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
powercap / RAPL: add support for ValleyView Soc
PM / sleep: Fix memory leak in pm_vt_switch_unregister().
cpufreq: Use CONFIG_CPU_FREQ_DEFAULT_* to set initial policy for setpolicy drivers
cpufreq: remove sysfs files for CPUs which failed to come back after resume
ACPI: Add BayTrail SoC GPIO and LPSS ACPI IDs
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* pm-cpufreq:
cpufreq: Use CONFIG_CPU_FREQ_DEFAULT_* to set initial policy for setpolicy drivers
cpufreq: remove sysfs files for CPUs which failed to come back after resume
* pm-sleep:
PM / sleep: Fix memory leak in pm_vt_switch_unregister().
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"Two fixes. One fixes a bug in the error path of cgroup_create(). The
other changes cgrp->id lifetime rule so that the id doesn't get
recycled before all controller states are destroyed. This premature
id recycling made memcg malfunction"
* 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: don't recycle cgroup id until all csses' have been destroyed
cgroup: fix cgroup_create() error handling path
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata
Pull libata fixes from Tejun Heo:
"There's one interseting commit - "libata, freezer: avoid block device
removal while system is frozen". It's an ugly hack working around a
deadlock condition between driver core resume and block layer device
removal paths through freezer which was made more reproducible by
writeback being converted to workqueue some releases ago. The bug has
nothing to do with libata but it's just an workaround which is easy to
backport. After discussion, Rafael and I seem to agree that we don't
really need kernel freezables - both kthread and workqueue. There are
few specific workqueues which constitute PM operations and require
freezing, which will be converted to use workqueue_set_max_active()
instead. All other kernel freezer uses are planned to be removed,
followed by the removal of kthread and workqueue freezer support,
hopefully.
Others are device-specific fixes. The most notable is the addition of
NO_NCQ_TRIM which is used to disable queued TRIM commands to Micro
M500 SSDs which otherwise suffers data corruption"
* 'for-3.13-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata:
libata, freezer: avoid block device removal while system is frozen
libata: implement ATA_HORKAGE_NO_NCQ_TRIM and apply it to Micro M500 SSDs
libata: disable a disk via libata.force params
ahci: bail out on ICH6 before using AHCI BAR
ahci: imx: Explicitly clear IMX6Q_GPR13_SATA_MPLL_CLK_EN
libata: add ATA_HORKAGE_BROKEN_FPDMA_AA quirk for Seagate Momentus SpinPoint M8
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Prior to 92bb1fcf57a0c2e45f7e67fbf0a8ed475a749236 (Only
do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD
systems), the comment here was accuate, but now we can
mostly avoid the extra rounding which causes the unlikey
to be actually likely here.
So remove the out of date comment.
Signed-off-by: John Stultz <[email protected]>
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Fix trivial comment typo for tk_setup_internals().
Signed-off-by: Yijing Wang <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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Since 48cdc135d4840 (Implement a shadow timekeeper), we have to
call timekeeping_update() after any adjustment to the timekeeping
structure in order to make sure that any adjustments to the structure
persist.
In the timekeeping suspend path, we udpate the timekeeper
structure, so we should be sure to update the shadow-timekeeper
before releasing the timekeeping locks. Currently this isn't done.
In most cases, the next time related code to run would be
timekeeping_resume, which does update the shadow-timekeeper, but
in an abundence of caution, this patch adds the call to
timekeeping_update() in the suspend path.
Cc: Sasha Levin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: stable <[email protected]> #3.10+
Signed-off-by: John Stultz <[email protected]>
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A think-o in the calculation of the monotonic -> tai time offset
results in CLOCK_TAI timers and nanosleeps to expire late (the
latency is ~2x the tai offset).
Fix this by adding the tai offset from the realtime offset instead
of subtracting.
Cc: Sasha Levin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: stable <[email protected]> #3.10+
Signed-off-by: John Stultz <[email protected]>
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Since the xtime lock was split into the timekeeping lock and
the jiffies lock, we no longer need to call update_wall_time()
while holding the jiffies lock.
Thus, this patch splits update_wall_time() out from do_timer().
This allows us to get away from calling clock_was_set_delayed()
in update_wall_time() and instead use the standard clock_was_set()
call that previously would deadlock, as it causes the jiffies lock
to be acquired.
Cc: Sasha Levin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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As part of normal operaions, the hrtimer subsystem frequently calls
into the timekeeping code, creating a locking order of
hrtimer locks -> timekeeping locks
clock_was_set_delayed() was suppoed to allow us to avoid deadlocks
between the timekeeping the hrtimer subsystem, so that we could
notify the hrtimer subsytem the time had changed while holding
the timekeeping locks. This was done by scheduling delayed work
that would run later once we were out of the timekeeing code.
But unfortunately the lock chains are complex enoguh that in
scheduling delayed work, we end up eventually trying to grab
an hrtimer lock.
Sasha Levin noticed this in testing when the new seqlock lockdep
enablement triggered the following (somewhat abrieviated) message:
[ 251.100221] ======================================================
[ 251.100221] [ INFO: possible circular locking dependency detected ]
[ 251.100221] 3.13.0-rc2-next-20131206-sasha-00005-g8be2375-dirty #4053 Not tainted
[ 251.101967] -------------------------------------------------------
[ 251.101967] kworker/10:1/4506 is trying to acquire lock:
[ 251.101967] (timekeeper_seq){----..}, at: [<ffffffff81160e96>] retrigger_next_event+0x56/0x70
[ 251.101967]
[ 251.101967] but task is already holding lock:
[ 251.101967] (hrtimer_bases.lock#11){-.-...}, at: [<ffffffff81160e7c>] retrigger_next_event+0x3c/0x70
[ 251.101967]
[ 251.101967] which lock already depends on the new lock.
[ 251.101967]
[ 251.101967]
[ 251.101967] the existing dependency chain (in reverse order) is:
[ 251.101967]
-> #5 (hrtimer_bases.lock#11){-.-...}:
[snipped]
-> #4 (&rt_b->rt_runtime_lock){-.-...}:
[snipped]
-> #3 (&rq->lock){-.-.-.}:
[snipped]
-> #2 (&p->pi_lock){-.-.-.}:
[snipped]
-> #1 (&(&pool->lock)->rlock){-.-...}:
[ 251.101967] [<ffffffff81194803>] validate_chain+0x6c3/0x7b0
[ 251.101967] [<ffffffff81194d9d>] __lock_acquire+0x4ad/0x580
[ 251.101967] [<ffffffff81194ff2>] lock_acquire+0x182/0x1d0
[ 251.101967] [<ffffffff84398500>] _raw_spin_lock+0x40/0x80
[ 251.101967] [<ffffffff81153e69>] __queue_work+0x1a9/0x3f0
[ 251.101967] [<ffffffff81154168>] queue_work_on+0x98/0x120
[ 251.101967] [<ffffffff81161351>] clock_was_set_delayed+0x21/0x30
[ 251.101967] [<ffffffff811c4bd1>] do_adjtimex+0x111/0x160
[ 251.101967] [<ffffffff811e2711>] compat_sys_adjtimex+0x41/0x70
[ 251.101967] [<ffffffff843a4b49>] ia32_sysret+0x0/0x5
[ 251.101967]
-> #0 (timekeeper_seq){----..}:
[snipped]
[ 251.101967] other info that might help us debug this:
[ 251.101967]
[ 251.101967] Chain exists of:
timekeeper_seq --> &rt_b->rt_runtime_lock --> hrtimer_bases.lock#11
[ 251.101967] Possible unsafe locking scenario:
[ 251.101967]
[ 251.101967] CPU0 CPU1
[ 251.101967] ---- ----
[ 251.101967] lock(hrtimer_bases.lock#11);
[ 251.101967] lock(&rt_b->rt_runtime_lock);
[ 251.101967] lock(hrtimer_bases.lock#11);
[ 251.101967] lock(timekeeper_seq);
[ 251.101967]
[ 251.101967] *** DEADLOCK ***
[ 251.101967]
[ 251.101967] 3 locks held by kworker/10:1/4506:
[ 251.101967] #0: (events){.+.+.+}, at: [<ffffffff81154960>] process_one_work+0x200/0x530
[ 251.101967] #1: (hrtimer_work){+.+...}, at: [<ffffffff81154960>] process_one_work+0x200/0x530
[ 251.101967] #2: (hrtimer_bases.lock#11){-.-...}, at: [<ffffffff81160e7c>] retrigger_next_event+0x3c/0x70
[ 251.101967]
[ 251.101967] stack backtrace:
[ 251.101967] CPU: 10 PID: 4506 Comm: kworker/10:1 Not tainted 3.13.0-rc2-next-20131206-sasha-00005-g8be2375-dirty #4053
[ 251.101967] Workqueue: events clock_was_set_work
So the best solution is to avoid calling clock_was_set_delayed() while
holding the timekeeping lock, and instead using a flag variable to
decide if we should call clock_was_set() once we've released the locks.
This works for the case here, where the do_adjtimex() was the deadlock
trigger point. Unfortuantely, in update_wall_time() we still hold
the jiffies lock, which would deadlock with the ipi triggered by
clock_was_set(), preventing us from calling it even after we drop the
timekeeping lock. So instead call clock_was_set_delayed() at that point.
Cc: Thomas Gleixner <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Sasha Levin <[email protected]>
Cc: stable <[email protected]> #3.10+
Reported-by: Sasha Levin <[email protected]>
Tested-by: Sasha Levin <[email protected]>
Signed-off-by: John Stultz <[email protected]>
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In 780427f0e11 (Indicate that clock was set in the pvclock
gtod notifier), logic was added to pass a CLOCK_WAS_SET
notification to the pvclock notifier chain.
While that patch added a action flag returned from
accumulate_nsecs_to_secs(), it only uses the returned value
in one location, and not in the logarithmic accumulation.
This means if a leap second triggered during the logarithmic
accumulation (which is most likely where it would happen),
the notification that the clock was set would not make it to
the pv notifiers.
This patch extends the logarithmic_accumulation pass down
that action flag so proper notification will occur.
This patch also changes the varialbe action -> clock_set
per Ingo's suggestion.
Cc: Sasha Levin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: David Vrabel <[email protected]>
Cc: Konrad Rzeszutek Wilk <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: <[email protected]>
Cc: stable <[email protected]> #3.11+
Signed-off-by: John Stultz <[email protected]>
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Since 48cdc135d4840 (Implement a shadow timekeeper), we have to
call timekeeping_update() after any adjustment to the timekeeping
structure in order to make sure that any adjustments to the structure
persist.
Unfortunately, the updates to the tai offset via adjtimex do not
trigger this update, causing adjustments to the tai offset to be
made and then over-written by the previous value at the next
update_wall_time() call.
This patch resovles the issue by calling timekeeping_update()
right after setting the tai offset.
Cc: Sasha Levin <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Prarit Bhargava <[email protected]>
Cc: Richard Cochran <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: stable <[email protected]> #3.10+
Signed-off-by: John Stultz <[email protected]>
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kmemleak reported a memory leak as below.
unreferenced object 0xffff880118f14700 (size 32):
comm "swapper/0", pid 1, jiffies 4294877401 (age 123.283s)
hex dump (first 32 bytes):
00 01 10 00 00 00 ad de 00 02 20 00 00 00 ad de .......... .....
00 d4 d2 18 01 88 ff ff 01 00 00 00 00 04 00 00 ................
backtrace:
[<ffffffff814edb1e>] kmemleak_alloc+0x4e/0xb0
[<ffffffff811889dc>] kmem_cache_alloc_trace+0x1ec/0x260
[<ffffffff810aba66>] pm_vt_switch_required+0x76/0xb0
[<ffffffff812f39f5>] register_framebuffer+0x195/0x320
[<ffffffff8130af18>] efifb_probe+0x718/0x780
[<ffffffff81391495>] platform_drv_probe+0x45/0xb0
[<ffffffff8138f407>] driver_probe_device+0x87/0x3a0
[<ffffffff8138f7f3>] __driver_attach+0x93/0xa0
[<ffffffff8138d413>] bus_for_each_dev+0x63/0xa0
[<ffffffff8138ee5e>] driver_attach+0x1e/0x20
[<ffffffff8138ea40>] bus_add_driver+0x180/0x250
[<ffffffff8138fe74>] driver_register+0x64/0xf0
[<ffffffff813913ba>] __platform_driver_register+0x4a/0x50
[<ffffffff8191e028>] efifb_driver_init+0x12/0x14
[<ffffffff8100214a>] do_one_initcall+0xfa/0x1b0
[<ffffffff818e40e0>] kernel_init_freeable+0x17b/0x201
In pm_vt_switch_required(), "entry" variable is allocated via kmalloc().
So, in pm_vt_switch_unregister(), it needs to call kfree() when object
is deleted from list.
Signed-off-by: Masami Ichikawa <[email protected]>
Reviewed-by: Pavel Machek <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>
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In struct page we have enough space to fit long-size page->ptl there,
but we use dynamically-allocated page->ptl if size(spinlock_t) is larger
than sizeof(int).
It hurts 64-bit architectures with CONFIG_GENERIC_LOCKBREAK, where
sizeof(spinlock_t) == 8, but it easily fits into struct page.
Signed-off-by: Kirill A. Shutemov <[email protected]>
Acked-by: Hugh Dickins <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull ftrace fix from Steven Rostedt:
"This fixes a long standing bug in the ftrace profiler. The problem is
that the profiler only initializes the online CPUs, and not possible
CPUs. This causes issues if the user takes CPUs online or offline
while the profiler is running.
If we online a CPU after starting the profiler, we lose all the trace
information on the CPU going online.
If we offline a CPU after running a test and start a new test, it will
not clear the old data from that CPU.
This bug causes incorrect data to be reported to the user if they
online or offline CPUs during the profiling"
* tag 'trace-fixes-v3.13-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
ftrace: Initialize the ftrace profiler for each possible cpu
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Freezable kthreads and workqueues are fundamentally problematic in
that they effectively introduce a big kernel lock widely used in the
kernel and have already been the culprit of several deadlock
scenarios. This is the latest occurrence.
During resume, libata rescans all the ports and revalidates all
pre-existing devices. If it determines that a device has gone
missing, the device is removed from the system which involves
invalidating block device and flushing bdi while holding driver core
layer locks. Unfortunately, this can race with the rest of device
resume. Because freezable kthreads and workqueues are thawed after
device resume is complete and block device removal depends on
freezable workqueues and kthreads (e.g. bdi_wq, jbd2) to make
progress, this can lead to deadlock - block device removal can't
proceed because kthreads are frozen and kthreads can't be thawed
because device resume is blocked behind block device removal.
839a8e8660b6 ("writeback: replace custom worker pool implementation
with unbound workqueue") made this particular deadlock scenario more
visible but the underlying problem has always been there - the
original forker task and jbd2 are freezable too. In fact, this is
highly likely just one of many possible deadlock scenarios given that
freezer behaves as a big kernel lock and we don't have any debug
mechanism around it.
I believe the right thing to do is getting rid of freezable kthreads
and workqueues. This is something fundamentally broken. For now,
implement a funny workaround in libata - just avoid doing block device
hot[un]plug while the system is frozen. Kernel engineering at its
finest. :(
v2: Add EXPORT_SYMBOL_GPL(pm_freezing) for cases where libata is built
as a module.
v3: Comment updated and polling interval changed to 10ms as suggested
by Rafael.
v4: Add #ifdef CONFIG_FREEZER around the hack as pm_freezing is not
defined when FREEZER is not configured thus breaking build.
Reported by kbuild test robot.
Signed-off-by: Tejun Heo <[email protected]>
Reported-by: Tomaž Šolc <[email protected]>
Reviewed-by: "Rafael J. Wysocki" <[email protected]>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=62801
Link: http://lkml.kernel.org/r/[email protected]
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: [email protected]
Cc: kbuild test robot <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"An RT group-scheduling fix and the sched-domains topology setup fix
from Mel"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/rt: Fix rq's cpupri leak while enqueue/dequeue child RT entities
sched: Assign correct scheduling domain to 'sd_llc'
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"An ABI documentation fix, and a mixed-PMU perf-info-corruption fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Document the new transaction sample type
perf: Disable all pmus on unthrottling and rescheduling
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Merge patches from Andrew Morton:
"23 fixes and a MAINTAINERS update"
* emailed patches from Andrew Morton <[email protected]>: (24 commits)
mm/hugetlb: check for pte NULL pointer in __page_check_address()
fix build with make 3.80
mm/mempolicy: fix !vma in new_vma_page()
MAINTAINERS: add Davidlohr as GPT maintainer
mm/memory-failure.c: recheck PageHuge() after hugetlb page migrate successfully
mm/compaction: respect ignore_skip_hint in update_pageblock_skip
mm/mempolicy: correct putback method for isolate pages if failed
mm: add missing dependency in Kconfig
sh: always link in helper functions extracted from libgcc
mm: page_alloc: exclude unreclaimable allocations from zone fairness policy
mm: numa: defer TLB flush for THP migration as long as possible
mm: numa: guarantee that tlb_flush_pending updates are visible before page table updates
mm: fix TLB flush race between migration, and change_protection_range
mm: numa: avoid unnecessary disruption of NUMA hinting during migration
mm: numa: clear numa hinting information on mprotect
sched: numa: skip inaccessible VMAs
mm: numa: avoid unnecessary work on the failure path
mm: numa: ensure anon_vma is locked to prevent parallel THP splits
mm: numa: do not clear PTE for pte_numa update
mm: numa: do not clear PMD during PTE update scan
...
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There are a few subtle races, between change_protection_range (used by
mprotect and change_prot_numa) on one side, and NUMA page migration and
compaction on the other side.
The basic race is that there is a time window between when the PTE gets
made non-present (PROT_NONE or NUMA), and the TLB is flushed.
During that time, a CPU may continue writing to the page.
This is fine most of the time, however compaction or the NUMA migration
code may come in, and migrate the page away.
When that happens, the CPU may continue writing, through the cached
translation, to what is no longer the current memory location of the
process.
This only affects x86, which has a somewhat optimistic pte_accessible.
All other architectures appear to be safe, and will either always flush,
or flush whenever there is a valid mapping, even with no permissions
(SPARC).
The basic race looks like this:
CPU A CPU B CPU C
load TLB entry
make entry PTE/PMD_NUMA
fault on entry
read/write old page
start migrating page
change PTE/PMD to new page
read/write old page [*]
flush TLB
reload TLB from new entry
read/write new page
lose data
[*] the old page may belong to a new user at this point!
The obvious fix is to flush remote TLB entries, by making sure that
pte_accessible aware of the fact that PROT_NONE and PROT_NUMA memory may
still be accessible if there is a TLB flush pending for the mm.
This should fix both NUMA migration and compaction.
[[email protected]: fix build]
Signed-off-by: Rik van Riel <[email protected]>
Signed-off-by: Mel Gorman <[email protected]>
Cc: Alex Thorlton <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Inaccessible VMA should not be trapping NUMA hint faults. Skip them.
Signed-off-by: Mel Gorman <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Cc: Alex Thorlton <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Commit 1b3a5d02ee07 ("reboot: move arch/x86 reboot= handling to generic
kernel") moved reboot= handling to generic code. In the process it also
removed the code in native_machine_shutdown() which are moving reboot
process to reboot_cpu/cpu0.
I guess that thought must have been that all reboot paths are calling
migrate_to_reboot_cpu(), so we don't need this special handling. But
kexec reboot path (kernel_kexec()) is not calling
migrate_to_reboot_cpu() so above change broke kexec. Now reboot can
happen on non-boot cpu and when INIT is sent in second kerneo to bring
up BP, it brings down the machine.
So start calling migrate_to_reboot_cpu() in kexec reboot path to avoid
this problem.
Bisected by WANG Chao.
Reported-by: Matthew Whitehead <[email protected]>
Reported-by: Dave Young <[email protected]>
Signed-off-by: Vivek Goyal <[email protected]>
Tested-by: Baoquan He <[email protected]>
Tested-by: WANG Chao <[email protected]>
Acked-by: H. Peter Anvin <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull crypto key patches from David Howells:
"There are four items:
- A patch to fix X.509 certificate gathering. The problem was that I
was coming up with a different path for signing_key.x509 in the
build directory if it didn't exist to if it did exist. This meant
that the X.509 cert container object file would be rebuilt on the
second rebuild in a build directory and the kernel would get
relinked.
- Unconditionally remove files generated by SYSTEM_TRUSTED_KEYRING=y
when doing make mrproper.
- Actually initialise the persistent-keyring semaphore for
init_user_ns. I have no idea why this works at all for users in
the base user namespace unless it's something to do with systemd
containerising the system.
- Documentation for module signing"
* 'keys-devel' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
Add Documentation/module-signing.txt file
KEYS: fix uninitialized persistent_keyring_register_sem
KEYS: Remove files generated when SYSTEM_TRUSTED_KEYRING=y
X.509: Fix certificate gathering
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"Three fixes for scheduler crashes, each triggers in relatively rare,
hardware environment dependent situations"
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/fair: Rework sched_fair time accounting
math64: Add mul_u64_u32_shr()
sched: Remove PREEMPT_NEED_RESCHED from generic code
sched: Initialize power_orig for overlapping groups
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When mutex debugging is enabled and an imbalanced mutex_unlock()
is called, we get the following, slightly confusing warning:
[ 364.208284] DEBUG_LOCKS_WARN_ON(lock->owner != current)
But in that case the warning is due to an imbalanced mutex_unlock() call,
and the lock->owner is NULL - so the message is misleading.
So improve the message by testing for this case specifically:
DEBUG_LOCKS_WARN_ON(!lock->owner)
Signed-off-by: Liu, Chuansheng <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Link: http://lkml.kernel.org/r/1386136693.3650.48.camel@cliu38-desktop-build
[ Improved the changelog, changed the patch to use !lock->owner consistently. ]
Signed-off-by: Ingo Molnar <[email protected]>
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Merge Linux 3.13-rc4, to refresh this rather old tree with the latest fixes.
Signed-off-by: Ingo Molnar <[email protected]>
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The original code is as intended and was meant to scale the difference
between the NUMA_PERIOD_THRESHOLD and local/remote ratio when adjusting
the scan period. The period_slot recalculation can be dropped.
Signed-off-by: Wanpeng Li <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Rik van Riel <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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group_faults
Use wrapper function task_faults_idx to calculate index in group_faults.
Signed-off-by: Wanpeng Li <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Rik van Riel <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Use wrapper function task_node to get node which task is on.
Signed-off-by: Wanpeng Li <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Reviewed-by: Naoya Horiguchi <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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commit 887c290e (sched/numa: Decide whether to favour task or group weights
based on swap candidate relationships) drop the check against
sysctl_numa_balancing_settle_count, this patch remove the sysctl.
Signed-off-by: Wanpeng Li <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Acked-by: David Rientjes <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Naoya Horiguchi <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Merge the latest batch of fixes before applying development patches.
Signed-off-by: Ingo Molnar <[email protected]>
|
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Vince Weaver reports that, on all architectures apart from ARM,
PERF_EVENT_IOC_PERIOD doesn't actually update the period until the next
event fires. This is counter-intuitive behaviour and is better dealt
with in the core code.
This patch ensures that the period is forcefully reset when dealing with
such a request in the core code. A subsequent patch removes the
equivalent hack from the ARM back-end.
Reported-by: Vince Weaver <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Signed-off-by: Will Deacon <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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This patch touches the RT group scheduling case.
Functions inc_rt_prio_smp() and dec_rt_prio_smp() change (global) rq's
priority, while rt_rq passed to them may be not the top-level rt_rq.
This is wrong, because changing of priority on a child level does not
guarantee that the priority is the highest all over the rq. So, this
leak makes RT balancing unusable.
The short example: the task having the highest priority among all rq's
RT tasks (no one other task has the same priority) are waking on a
throttle rt_rq. The rq's cpupri is set to the task's priority
equivalent, but real rq->rt.highest_prio.curr is less.
The patch below fixes the problem.
Signed-off-by: Kirill Tkhai <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
CC: Steven Rostedt <[email protected]>
CC: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Commit 42eb088e (sched: Avoid NULL dereference on sd_busy) corrected a NULL
dereference on sd_busy but the fix also altered what scheduling domain it
used for the 'sd_llc' percpu variable.
One impact of this is that a task selecting a runqueue may consider
idle CPUs that are not cache siblings as candidates for running.
Tasks are then running on CPUs that are not cache hot.
This was found through bisection where ebizzy threads were not seeing equal
performance and it looked like a scheduling fairness issue. This patch
mitigates but does not completely fix the problem on all machines tested
implying there may be an additional bug or a common root cause. Here are
the average range of performance seen by individual ebizzy threads. It
was tested on top of candidate patches related to x86 TLB range flushing.
4-core machine
3.13.0-rc3 3.13.0-rc3
vanilla fixsd-v3r3
Mean 1 0.00 ( 0.00%) 0.00 ( 0.00%)
Mean 2 0.34 ( 0.00%) 0.10 ( 70.59%)
Mean 3 1.29 ( 0.00%) 0.93 ( 27.91%)
Mean 4 7.08 ( 0.00%) 0.77 ( 89.12%)
Mean 5 193.54 ( 0.00%) 2.14 ( 98.89%)
Mean 6 151.12 ( 0.00%) 2.06 ( 98.64%)
Mean 7 115.38 ( 0.00%) 2.04 ( 98.23%)
Mean 8 108.65 ( 0.00%) 1.92 ( 98.23%)
8-core machine
Mean 1 0.00 ( 0.00%) 0.00 ( 0.00%)
Mean 2 0.40 ( 0.00%) 0.21 ( 47.50%)
Mean 3 23.73 ( 0.00%) 0.89 ( 96.25%)
Mean 4 12.79 ( 0.00%) 1.04 ( 91.87%)
Mean 5 13.08 ( 0.00%) 2.42 ( 81.50%)
Mean 6 23.21 ( 0.00%) 69.46 (-199.27%)
Mean 7 15.85 ( 0.00%) 101.72 (-541.77%)
Mean 8 109.37 ( 0.00%) 19.13 ( 82.51%)
Mean 12 124.84 ( 0.00%) 28.62 ( 77.07%)
Mean 16 113.50 ( 0.00%) 24.16 ( 78.71%)
It's eliminated for one machine and reduced for another.
Signed-off-by: Mel Gorman <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Alex Shi <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Fengguang Wu <[email protected]>
Cc: H Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Currently, only one PMU in a context gets disabled during unthrottling
and event_sched_{out,in}(), however, events in one context may belong to
different pmus, which results in PMUs being reprogrammed while they are
still enabled.
This means that mixed PMU use [which is rare in itself] resulted in
potentially completely unreliable results: corrupted events, bogus
results, etc.
This patch temporarily disables PMUs that correspond to
each event in the context while these events are being modified.
Signed-off-by: Alexander Shishkin <[email protected]>
Reviewed-by: Andi Kleen <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Paul Mackerras <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Link: http://lkml.kernel.org/r/1387196256-8030-1-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <[email protected]>
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|
Hugh reported this bug:
> CONFIG_MEMCG_SWAP is broken in 3.13-rc. Try something like this:
>
> mkdir -p /tmp/tmpfs /tmp/memcg
> mount -t tmpfs -o size=1G tmpfs /tmp/tmpfs
> mount -t cgroup -o memory memcg /tmp/memcg
> mkdir /tmp/memcg/old
> echo 512M >/tmp/memcg/old/memory.limit_in_bytes
> echo $$ >/tmp/memcg/old/tasks
> cp /dev/zero /tmp/tmpfs/zero 2>/dev/null
> echo $$ >/tmp/memcg/tasks
> rmdir /tmp/memcg/old
> sleep 1 # let rmdir work complete
> mkdir /tmp/memcg/new
> umount /tmp/tmpfs
> dmesg | grep WARNING
> rmdir /tmp/memcg/new
> umount /tmp/memcg
>
> Shows lots of WARNING: CPU: 1 PID: 1006 at kernel/res_counter.c:91
> res_counter_uncharge_locked+0x1f/0x2f()
>
> Breakage comes from 34c00c319ce7 ("memcg: convert to use cgroup id").
>
> The lifetime of a cgroup id is different from the lifetime of the
> css id it replaced: memsw's css_get()s do nothing to hold on to the
> old cgroup id, it soon gets recycled to a new cgroup, which then
> mysteriously inherits the old's swap, without any charge for it.
Instead of removing cgroup id right after all the csses have been
offlined, we should do that after csses have been destroyed.
To make sure an invalid css pointer won't be returned after the css
is destroyed, make sure css_from_id() returns NULL in this case.
tj: Updated comment to note planned changes for cgrp->id.
Reported-by: Hugh Dickins <[email protected]>
Signed-off-by: Li Zefan <[email protected]>
Reviewed-by: Michal Hocko <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
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|
Ftrace currently initializes only the online CPUs. This implementation has
two problems:
- If we online a CPU after we enable the function profile, and then run the
test, we will lose the trace information on that CPU.
Steps to reproduce:
# echo 0 > /sys/devices/system/cpu/cpu1/online
# cd <debugfs>/tracing/
# echo <some function name> >> set_ftrace_filter
# echo 1 > function_profile_enabled
# echo 1 > /sys/devices/system/cpu/cpu1/online
# run test
- If we offline a CPU before we enable the function profile, we will not clear
the trace information when we enable the function profile. It will trouble
the users.
Steps to reproduce:
# cd <debugfs>/tracing/
# echo <some function name> >> set_ftrace_filter
# echo 1 > function_profile_enabled
# run test
# cat trace_stat/function*
# echo 0 > /sys/devices/system/cpu/cpu1/online
# echo 0 > function_profile_enabled
# echo 1 > function_profile_enabled
# cat trace_stat/function*
# run test
# cat trace_stat/function*
So it is better that we initialize the ftrace profiler for each possible cpu
every time we enable the function profile instead of just the online ones.
Link: http://lkml.kernel.org/r/[email protected]
Cc: [email protected] # 2.6.31+
Signed-off-by: Miao Xie <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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|
Merge Linux 3.13-rc4, to refresh this branch with the latest fixes.
Signed-off-by: Ingo Molnar <[email protected]>
|