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git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag
Pull metag architecture fix from James Hogan:
"A single fix for a boot crash since a commit in the merge window.
Metag was unusual in calling show_mem() early, before setup_per_cpu_pageset(),
which is no longer safe. It doesn't add much value to the log, so the
fix just drops the call"
* tag 'metag-for-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag:
metag: Drop show_mem() from mem_init()
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If get_maintainer is not given any filename arguments on the command line,
the standard input is read for a patch.
But checking if a VCS has a file named &STDIN is not a good idea and fails.
Verify the nominal input file is not &STDIN before checking the VCS.
Fixes: 4cad35a7ca69 ("get_maintainer.pl: reduce need for command-line option -f")
Reported-by: Christopher Covington <[email protected]>
Signed-off-by: Joe Perches <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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We have some tests that assume we're using std=gnu99, which is fine on
most compilers, but some old compilers use a different default.
So make it explicit that we want to use std=gnu99.
Signed-off-by: Michael Ellerman <[email protected]>
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For SKL and later Intel chips, we control the power well per codec
basis via link_power callback since the commit [03b135cebc47: ALSA:
hda - remove dependency on i915 power well for SKL].
However, there are a few exceptional cases where the gfx registers are
accessed from the audio driver: namely the wakeup override bit
toggling at (both system and runtime) resume. This seems causing a
kernel warning when accessed during the power well down (and likely
resulting in the bogus register accesses).
This patch puts the proper power up / down sequence around the resume
code so that the wakeup bit is fiddled properly while the power is
up. (The other callback, sync_audio_rate, is used only in the PCM
callback, so it's guaranteed in the power-on.)
Also, by this proper power up/down, the instantaneous flip of wakeup
bit in the resume callback that was introduced by the commit
[033ea349a7cd: ALSA: hda - Fix Skylake codec timeout] becomes
superfluous, as snd_hdac_display_power() already does it. So we can
clean it up together.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=96214
Fixes: 03b135cebc47 ('ALSA: hda - remove dependency on i915 power well for SKL')
Cc: <[email protected]> # v4.2+
Tested-by: Hans de Goede <[email protected]>
Signed-off-by: Takashi Iwai <[email protected]>
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When using if_changed, we need to add FORCE as a dependency (see
Documentation/kbuild/makefiles.txt) otherwise we don't get command line
change checking amongst other things. This has resulted in vdsos not
being rebuilt when switching between big and little endian.
The vdso64/32ld commands have to be changed around to avoid pulling
FORCE into the linker command line (code copied from x86).
Signed-off-by: Nicholas Piggin <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
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When we introduced the little endian support, we added the endian flags
to CC directly using override. I don't know the history of why we did
that, I suspect no one does.
Although this mostly works, it has one bug, which is that CROSS32CC
doesn't get -mbig-endian. That means when the compiler is little endian
by default and the user is building big endian, vdso32 is incorrectly
compiled as little endian and the kernel fails to build.
Instead we can add the endian flags to cflags-y/aflags-y, and then
append those to KBUILD_CFLAGS/KBUILD_AFLAGS.
This has the advantage of being 1) less ugly, 2) the documented way of
adding flags in the arch Makefile and 3) it fixes building vdso32 with a
LE toolchain.
Signed-off-by: Michael Ellerman <[email protected]>
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Ville Syrjälä reports "The first time I run hwclock after rebooting
I get this:
open("/dev/rtc", O_RDONLY) = 3
ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = 0
select(4, [3], NULL, NULL, {10, 0}) = 0 (Timeout)
ioctl(3, PHN_NOT_OH or RTC_UIE_OFF, 0) = 0
close(3) = 0
On all subsequent runs I get this:
open("/dev/rtc", O_RDONLY) = 3
ioctl(3, PHN_SET_REGS or RTC_UIE_ON, 0) = -1 EINVAL (Invalid argument)
ioctl(3, RTC_RD_TIME, 0x7ffd76b3ae70) = -1 EINVAL (Invalid argument)
close(3) = 0"
This was caused by a stupid typo in a patch that should have been
a simple rename to move around contents of a header file, but
accidentally wrote zeroes into the rtc rather than reading from
it:
463a86304cae ("char/genrtc: x86: remove remnants of asm/rtc.h")
Reported-by: Ville Syrjälä <[email protected]>
Tested-by: Jarkko Nikula <[email protected]>
Tested-by: Ville Syrjälä <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
Cc: Alessandro Zummo <[email protected]>
Cc: Alexandre Belloni <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Geert Uytterhoeven <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Fixes: 463a86304cae ("char/genrtc: x86: remove remnants of asm/rtc.h")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Signed-off-by: Ingo Molnar <[email protected]>
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It's obviously wrong to set stat to NULL. So lets remove it.
Otherwise it is always zero when we check the latency of kick/wake.
Signed-off-by: Pan Xinhui <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Waiman Long <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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When the lock holder vCPU is racing with the queue head:
CPU 0 (lock holder) CPU1 (queue head)
=================== =================
spin_lock(); spin_lock();
pv_kick_node(): pv_wait_head_or_lock():
if (!lp) {
lp = pv_hash(lock, pn);
xchg(&l->locked, _Q_SLOW_VAL);
}
WRITE_ONCE(pn->state, vcpu_halted);
cmpxchg(&pn->state,
vcpu_halted, vcpu_hashed);
WRITE_ONCE(l->locked, _Q_SLOW_VAL);
(void)pv_hash(lock, pn);
In this case, lock holder inserts the pv_node of queue head into the
hash table and set _Q_SLOW_VAL unnecessary. This patch avoids it by
restoring/setting vcpu_hashed state after failing adaptive locking
spinning.
Signed-off-by: Wanpeng Li <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Pan Xinhui <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Waiman Long <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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This patch aims to get rid of endianness in queued_write_unlock(). We
want to set __qrwlock->wmode to NULL, however the address is not
&lock->cnts in big endian machine. That causes queued_write_unlock()
write NULL to the wrong field of __qrwlock.
So implement __qrwlock_write_byte() which returns the correct
__qrwlock->wmode address.
Suggested-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Pan Xinhui <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Signed-off-by: Ingo Molnar <[email protected]>
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The following warning can be triggered by hot-unplugging the CPU
on which an active SCHED_DEADLINE task is running on:
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0
releasing a pinned lock
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
? dl_task_timer+0x1a1/0x2b0
warn_slowpath_fmt+0x4f/0x60
? sched_clock+0x13/0x20
lock_release+0x690/0x6a0
? enqueue_pushable_dl_task+0x9b/0xa0
? enqueue_task_dl+0x1ca/0x480
_raw_spin_unlock+0x1f/0x40
dl_task_timer+0x1a1/0x2b0
? push_dl_task.part.31+0x190/0x190
WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0
unpinning an unpinned lock
Call Trace:
dump_stack+0x99/0xd0
__warn+0xd1/0xf0
warn_slowpath_fmt+0x4f/0x60
lock_unpin_lock+0x181/0x1a0
dl_task_timer+0x127/0x2b0
? push_dl_task.part.31+0x190/0x190
As per the comment before this code, its safe to drop the RQ lock
here, and since we (potentially) change rq, unpin and repin to avoid
the splat.
Signed-off-by: Wanpeng Li <[email protected]>
[ Rewrote changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Luca Abeni <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Commit:
6e998916dfe3 ("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency")
fixed a problem whereby clock_nanosleep() followed by clock_gettime() could
allow a task to wake early. It addressed the problem by calling the scheduling
classes update_curr() when the cputimer starts.
Said change induced a considerable performance regression on the syscalls
times() and clock_gettimes(CLOCK_PROCESS_CPUTIME_ID). There are some
debuggers and applications that monitor their own performance that
accidentally depend on the performance of these specific calls.
This patch mitigates the performace loss by prefetching data in the CPU
cache, as stalls due to cache misses appear to be where most time is spent
in our benchmarks.
Here are the performance gain of this patch over v4.7-rc7 on a Sandy Bridge
box with 32 logical cores and 2 NUMA nodes. The test is repeated with a
variable number of threads, from 2 to 4*num_cpus; the results are in
seconds and correspond to the average of 10 runs; the percentage gain is
computed with (before-after)/before so a positive value is an improvement
(it's faster). The improvement varies between a few percents for 5-20
threads and more than 10% for 2 or >20 threads.
pound_clock_gettime:
threads 4.7-rc7 patched 4.7-rc7
[num] [secs] [secs (percent)]
2 3.48 3.06 ( 11.83%)
5 3.33 3.25 ( 2.40%)
8 3.37 3.26 ( 3.30%)
12 3.32 3.37 ( -1.60%)
21 4.01 3.90 ( 2.74%)
30 3.63 3.36 ( 7.41%)
48 3.71 3.11 ( 16.27%)
79 3.75 3.16 ( 15.74%)
110 3.81 3.25 ( 14.80%)
128 3.88 3.31 ( 14.76%)
pound_times:
threads 4.7-rc7 patched 4.7-rc7
[num] [secs] [secs (percent)]
2 3.65 3.25 ( 11.03%)
5 3.45 3.17 ( 7.92%)
8 3.52 3.22 ( 8.69%)
12 3.29 3.36 ( -2.04%)
21 4.07 3.92 ( 3.78%)
30 3.87 3.40 ( 12.17%)
48 3.79 3.16 ( 16.61%)
79 3.88 3.28 ( 15.42%)
110 3.90 3.38 ( 13.35%)
128 4.00 3.38 ( 15.45%)
pound_clock_gettime and pound_clock_gettime are two benchmarks included in
the MMTests framework. They launch a given number of threads which
repeatedly call times() or clock_gettimes(). The results above can be
reproduced with cloning MMTests from github.com and running the "poundtime"
workload:
$ git clone https://github.com/gormanm/mmtests.git
$ cd mmtests
$ cp configs/config-global-dhp__workload_poundtime config
$ ./run-mmtests.sh --run-monitor $(uname -r)
The above will run "poundtime" measuring the kernel currently running on
the machine; Once a new kernel is installed and the machine rebooted,
running again
$ cd mmtests
$ ./run-mmtests.sh --run-monitor $(uname -r)
will produce results to compare with. A comparison table will be output
with:
$ cd mmtests/work/log
$ ../../compare-kernels.sh
the table will contain a lot of entries; grepping for "Amean" (as in
"arithmetic mean") will give the tables presented above. The source code
for the two benchmarks is reported at the end of this changelog for
clairity.
The cache misses addressed by this patch were found using a combination of
`perf top`, `perf record` and `perf annotate`. The incriminated lines were
found to be
struct sched_entity *curr = cfs_rq->curr;
and
delta_exec = now - curr->exec_start;
in the function update_curr() from kernel/sched/fair.c. This patch
prefetches the data from memory just before update_curr is called in the
interested execution path.
A comparison of the total number of cycles before and after the patch
follows; the data is obtained using `perf stat -r 10 -ddd <program>`
running over the same sequence of number of threads used above (a positive
gain is an improvement):
threads cycles before cycles after gain
2 19,699,563,964 +-1.19% 17,358,917,517 +-1.85% 11.88%
5 47,401,089,566 +-2.96% 45,103,730,829 +-0.97% 4.85%
8 80,923,501,004 +-3.01% 71,419,385,977 +-0.77% 11.74%
12 112,326,485,473 +-0.47% 110,371,524,403 +-0.47% 1.74%
21 193,455,574,299 +-0.72% 180,120,667,904 +-0.36% 6.89%
30 315,073,519,013 +-1.64% 271,222,225,950 +-1.29% 13.92%
48 321,969,515,332 +-1.48% 273,353,977,321 +-1.16% 15.10%
79 337,866,003,422 +-0.97% 289,462,481,538 +-1.05% 14.33%
110 338,712,691,920 +-0.78% 290,574,233,170 +-0.77% 14.21%
128 348,384,794,006 +-0.50% 292,691,648,206 +-0.66% 15.99%
A comparison of cache miss vs total cache loads ratios, before and after
the patch (again from the `perf stat -r 10 -ddd <program>` tables):
threads L1 misses/total*100 L1 misses/total*100 gain
before after
2 7.43 +-4.90% 7.36 +-4.70% 0.94%
5 13.09 +-4.74% 13.52 +-3.73% -3.28%
8 13.79 +-5.61% 12.90 +-3.27% 6.45%
12 11.57 +-2.44% 8.71 +-1.40% 24.72%
21 12.39 +-3.92% 9.97 +-1.84% 19.53%
30 13.91 +-2.53% 11.73 +-2.28% 15.67%
48 13.71 +-1.59% 12.32 +-1.97% 10.14%
79 14.44 +-0.66% 13.40 +-1.06% 7.20%
110 15.86 +-0.50% 14.46 +-0.59% 8.83%
128 16.51 +-0.32% 15.06 +-0.78% 8.78%
As a final note, the following shows the evolution of performance figures
in the "poundtime" benchmark and pinpoints commit 6e998916dfe3
("sched/cputime: Fix clock_nanosleep()/clock_gettime() inconsistency") as a
major source of degradation, mostly unaddressed to this day (figures
expressed in seconds).
pound_clock_gettime:
threads parent of 6e998916dfe3 4.7-rc7
6e998916dfe3 itself
2 2.23 3.68 ( -64.56%) 3.48 (-55.48%)
5 2.83 3.78 ( -33.42%) 3.33 (-17.43%)
8 2.84 4.31 ( -52.12%) 3.37 (-18.76%)
12 3.09 3.61 ( -16.74%) 3.32 ( -7.17%)
21 3.14 4.63 ( -47.36%) 4.01 (-27.71%)
30 3.28 5.75 ( -75.37%) 3.63 (-10.80%)
48 3.02 6.05 (-100.56%) 3.71 (-22.99%)
79 2.88 6.30 (-118.90%) 3.75 (-30.26%)
110 2.95 6.46 (-119.00%) 3.81 (-29.24%)
128 3.05 6.42 (-110.08%) 3.88 (-27.04%)
pound_times:
threads parent of 6e998916dfe3 4.7-rc7
6e998916dfe3 itself
2 2.27 3.73 ( -64.71%) 3.65 (-61.14%)
5 2.78 3.77 ( -35.56%) 3.45 (-23.98%)
8 2.79 4.41 ( -57.71%) 3.52 (-26.05%)
12 3.02 3.56 ( -17.94%) 3.29 ( -9.08%)
21 3.10 4.61 ( -48.74%) 4.07 (-31.34%)
30 3.33 5.75 ( -72.53%) 3.87 (-16.01%)
48 2.96 6.06 (-105.04%) 3.79 (-28.10%)
79 2.88 6.24 (-116.83%) 3.88 (-34.81%)
110 2.98 6.37 (-114.08%) 3.90 (-31.12%)
128 3.10 6.35 (-104.61%) 4.00 (-28.87%)
The source code of the two benchmarks follows. To compile the two:
NR_THREADS=42
for FILE in pound_times pound_clock_gettime; do
gcc -lrt -O2 -lpthread -DNUM_THREADS=$NR_THREADS $FILE.c -o $FILE
done
==== BEGIN pound_times.c ====
struct tms start;
void *pound (void *threadid)
{
struct tms end;
int oldutime = 0;
int utime;
int i;
for (i = 0; i < 5000000 / NUM_THREADS; i++) {
times(&end);
utime = ((int)end.tms_utime - (int)start.tms_utime);
if (oldutime > utime) {
printf("utime decreased, was %d, now %d!\n", oldutime, utime);
}
oldutime = utime;
}
pthread_exit(NULL);
}
int main()
{
pthread_t th[NUM_THREADS];
long i;
times(&start);
for (i = 0; i < NUM_THREADS; i++) {
pthread_create (&th[i], NULL, pound, (void *)i);
}
pthread_exit(NULL);
return 0;
}
==== END pound_times.c ====
==== BEGIN pound_clock_gettime.c ====
void *pound (void *threadid)
{
struct timespec ts;
int rc, i;
unsigned long prev = 0, this = 0;
for (i = 0; i < 5000000 / NUM_THREADS; i++) {
rc = clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts);
if (rc < 0)
perror("clock_gettime");
this = (ts.tv_sec * 1000000000) + ts.tv_nsec;
if (0 && this < prev)
printf("%lu ns timewarp at iteration %d\n", prev - this, i);
prev = this;
}
pthread_exit(NULL);
}
int main()
{
pthread_t th[NUM_THREADS];
long rc, i;
pid_t pgid;
for (i = 0; i < NUM_THREADS; i++) {
rc = pthread_create(&th[i], NULL, pound, (void *)i);
if (rc < 0)
perror("pthread_create");
}
pthread_exit(NULL);
return 0;
}
==== END pound_clock_gettime.c ====
Suggested-by: Mike Galbraith <[email protected]>
Signed-off-by: Giovanni Gherdovich <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stanislaw Gruszka <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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We should update cfs_rq->throttled_clock_task, not
pcfs_rq->throttle_clock_task.
The effects of this bug was probably occasionally erratic
group scheduling, particularly in cgroups-intense workloads.
Signed-off-by: Xunlei Pang <[email protected]>
[ Added changelog. ]
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Konstantin Khlebnikov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: 55e16d30bd99 ("sched/fair: Rework throttle_count sync")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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Current code in cpudeadline.c has a bug in re-heapifying when adding a
new element at the end of the heap, because a deadline value of 0 is
temporarily set in the new elem, then cpudl_change_key() is called
with the actual elem deadline as param.
However, the function compares the new deadline to set with the one
previously in the elem, which is 0. So, if current absolute deadlines
grew so much to have negative values as s64, the comparison in
cpudl_change_key() makes the wrong decision. Instead, as from
dl_time_before(), the kernel should handle correctly abs deadlines
wrap-arounds.
This patch fixes the problem with a minimally invasive change that
forces cpudl_change_key() to heapify up in this case.
Signed-off-by: Tommaso Cucinotta <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Luca Abeni <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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There's a perf stat bug easy to observer on a machine with only one cgroup:
$ perf stat -e cycles -I 1000 -C 0 -G /
# time counts unit events
1.000161699 <not counted> cycles /
2.000355591 <not counted> cycles /
3.000565154 <not counted> cycles /
4.000951350 <not counted> cycles /
We'd expect some output there.
The underlying problem is that there is an optimization in
perf_cgroup_sched_{in,out}() that skips the switch of cgroup events
if the old and new cgroups in a task switch are the same.
This optimization interacts with the current code in two ways
that cause a CPU context's cgroup (cpuctx->cgrp) to be NULL even if a
cgroup event matches the current task. These are:
1. On creation of the first cgroup event in a CPU: In current code,
cpuctx->cpu is only set in perf_cgroup_sched_in, but due to the
aforesaid optimization, perf_cgroup_sched_in will run until the next
cgroup switches in that CPU. This may happen late or never happen,
depending on system's number of cgroups, CPU load, etc.
2. On deletion of the last cgroup event in a cpuctx: In list_del_event,
cpuctx->cgrp is set NULL. Any new cgroup event will not be sched in
because cpuctx->cgrp == NULL until a cgroup switch occurs and
perf_cgroup_sched_in is executed (updating cpuctx->cgrp).
This patch fixes both problems by setting cpuctx->cgrp in list_add_event,
mirroring what list_del_event does when removing a cgroup event from CPU
context, as introduced in:
commit 68cacd29167b ("perf_events: Fix stale ->cgrp pointer in update_cgrp_time_from_cpuctx()")
With this patch, cpuctx->cgrp is always set/clear when installing/removing
the first/last cgroup event in/from the CPU context. With cpuctx->cgrp
correctly set, event_filter_match works as intended when events are
sched in/out.
After the fix, the output is as expected:
$ perf stat -e cycles -I 1000 -a -G /
# time counts unit events
1.004699159 627342882 cycles /
2.007397156 615272690 cycles /
3.010019057 616726074 cycles /
Signed-off-by: David Carrillo-Cisneros <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paul Turner <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vegard Nossum <[email protected]>
Cc: Vince Weaver <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
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deference crash
Vegard Nossum reported that perf fuzzing generates a NULL
pointer dereference crash:
> Digging a bit deeper into this, it seems the event itself is getting
> created by perf_event_open() and it gets added to the pmu_event_list
> through:
>
> perf_event_open()
> - perf_event_alloc()
> - account_event()
> - account_pmu_sb_event()
> - attach_sb_event()
>
> so at this point the event is being attached but its ->ctx is still
> NULL. It seems like ->ctx is set just a bit later in
> perf_event_open(), though.
>
> But before that, __schedule() comes along and creates a stack trace
> similar to the one above:
>
> __schedule()
> - __perf_event_task_sched_out()
> - perf_iterate_sb()
> - perf_iterate_sb_cpu()
> - event_filter_match()
> - perf_cgroup_match()
> - __get_cpu_context()
> - (dereference ctx which is NULL)
>
> So I guess the question is... should the event be attached (= put on
> the list) before ->ctx gets set? Or should the cgroup code check for a
> NULL ->ctx?
The latter seems like the simplest solution. Moving the list-add later
creates a bit of a mess.
Reported-by: Vegard Nossum <[email protected]>
Tested-by: Vegard Nossum <[email protected]>
Tested-by: Vince Weaver <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: David Carrillo-Cisneros <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Stephane Eranian <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Fixes: f2fb6bef9251 ("perf/core: Optimize side-band event delivery")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
This patch eliminates a source of imprecise APIC timer interrupts,
which imprecision may result in double interrupts or even late
interrupts.
The TSC deadline clockevent devices' configuration and registration
happens before the TSC frequency calibration is refined in
tsc_refine_calibration_work().
This results in the TSC clocksource and the TSC deadline clockevent
devices being configured with slightly different frequencies: the former
gets the refined one and the latter are configured with the inaccurate
frequency detected earlier by means of the "Fast TSC calibration using PIT".
Within the APIC code, introduce the notifier function
lapic_update_tsc_freq() which reconfigures all per-CPU TSC deadline
clockevent devices with the current tsc_khz.
Call it from the TSC code after TSC calibration refinement has happened.
Signed-off-by: Nicolai Stange <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christopher S. Hall <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hidehiro Kawai <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Viresh Kumar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Pushed #ifdef CONFIG_X86_LOCAL_APIC into header, improved changelog. ]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
clockevents frequency roundoff error
I noticed the following bug/misbehavior on certain Intel systems: with a
single task running on a NOHZ CPU on an Intel Haswell, I recognized
that I did not only get the one expected local_timer APIC interrupt, but
two per second at minimum. (!)
Further tracing showed that the first one precedes the programmed deadline
by up to ~50us and hence, it did nothing except for reprogramming the TSC
deadline clockevent device to trigger shortly thereafter again.
The reason for this is imprecise calibration, the timeout we program into
the APIC results in 'too short' timer interrupts. The core (hr)timer code
notices this (because it has a precise ktime source and sees the short
interrupt) and fixes it up by programming an additional very short
interrupt period.
This is obviously suboptimal.
The reason for the imprecise calibration is twofold, and this patch
fixes the first reason:
In setup_APIC_timer(), the registered clockevent device's frequency
is calculated by first dividing tsc_khz by TSC_DIVISOR and multiplying
it with 1000 afterwards:
(tsc_khz / TSC_DIVISOR) * 1000
The multiplication with 1000 is done for converting from kHz to Hz and the
division by TSC_DIVISOR is carried out in order to make sure that the final
result fits into an u32.
However, with the order given in this calculation, the roundoff error
introduced by the division gets magnified by a factor of 1000 by the
following multiplication.
To fix it, reversing the order of the division and the multiplication a la:
(tsc_khz * 1000) / TSC_DIVISOR
... reduces the roundoff error already.
Furthermore, if TSC_DIVISOR divides 1000, associativity holds:
(tsc_khz * 1000) / TSC_DIVISOR = tsc_khz * (1000 / TSC_DIVISOR)
and thus, the roundoff error even vanishes and the whole operation can be
carried out within 32 bits.
The powers of two that divide 1000 are 2, 4 and 8. A value of 8 for
TSC_DIVISOR still allows for TSC frequencies up to
2^32 / 10^9ns * 8 = 34.4GHz which is way larger than anything to expect
in the next years.
Thus we also replace the current TSC_DIVISOR value of 32 by 8. Reverse
the order of the divison and the multiplication in the calculation of
the registered clockevent device's frequency.
Signed-off-by: Nicolai Stange <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Paolo Bonzini <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christopher S. Hall <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hidehiro Kawai <[email protected]>
Cc: Len Brown <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Viresh Kumar <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
[ Improved changelog. ]
Signed-off-by: Ingo Molnar <[email protected]>
|
|
We cannot do those initializations from apply_feature_fixups() as
this function runs in a very restricted environment on 32-bit where
the kernel isn't running at its linked address and the PTRRELOC()
macro must be used for any global accesss.
Instead, split them into a separtate steup_feature_keys() function
which is called in a more suitable spot on ppc32.
Fixes: 309b315b6ec6 ("powerpc: Call jump_label_init() in apply_feature_fixups()")
Reported-and-tested-by: Christian Kujau <[email protected]>
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
|
|
We don't identify the machine type anymore...
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
|
|
This makes it easier to debug crashes that happen very early before
the kernel takes over Open Firmware by allowing us to relate the OF
reported crashing addresses to offsets within the kernel.
Signed-off-by: Benjamin Herrenschmidt <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
|
|
Commit 8d460f6156cd ("powerpc/process: Add the function
flush_tmregs_to_thread") added flush_tmregs_to_thread() and included
the assumption that it would only be called for a task which is not
current.
Although this is correct for ptrace, when generating a core dump, some
of the routines which call flush_tmregs_to_thread() are called. This
leads to a WARNing such as:
Not expecting ptrace on self: TM regs may be incorrect
------------[ cut here ]------------
WARNING: CPU: 123 PID: 7727 at arch/powerpc/kernel/process.c:1088 flush_tmregs_to_thread+0x78/0x80
CPU: 123 PID: 7727 Comm: libvirtd Not tainted 4.8.0-rc1-gcc6x-g61e8a0d #1
task: c000000fe631b600 task.stack: c000000fe63b0000
NIP: c00000000001a1a8 LR: c00000000001a1a4 CTR: c000000000717780
REGS: c000000fe63b3420 TRAP: 0700 Not tainted (4.8.0-rc1-gcc6x-g61e8a0d)
MSR: 900000010282b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE,TM[E]> CR: 28004222 XER: 20000000
...
NIP [c00000000001a1a8] flush_tmregs_to_thread+0x78/0x80
LR [c00000000001a1a4] flush_tmregs_to_thread+0x74/0x80
Call Trace:
flush_tmregs_to_thread+0x74/0x80 (unreliable)
vsr_get+0x64/0x1a0
elf_core_dump+0x604/0x1430
do_coredump+0x5fc/0x1200
get_signal+0x398/0x740
do_signal+0x54/0x2b0
do_notify_resume+0x98/0xb0
ret_from_except_lite+0x70/0x74
So fix flush_tmregs_to_thread() to detect the case where it is called on
current, and a transaction is active, and in that case flush the TM regs
to the thread_struct.
This patch also moves flush_tmregs_to_thread() into ptrace.c as it is
only called from that file.
Fixes: 8d460f6156cd ("powerpc/process: Add the function flush_tmregs_to_thread")
Signed-off-by: Cyril Bur <[email protected]>
[mpe: Flesh out change log]
Signed-off-by: Michael Ellerman <[email protected]>
|
|
Commit 7aef4136566b0 ("powerpc32: rewrite csum_partial_copy_generic()
based on copy_tofrom_user()") introduced a bug when destination
address is odd and initial csum is not null
In that (rare) case the initial csum value has to be rotated one byte
as well as the resulting value is
This patch also fixes related comments
Fixes: 7aef4136566b0 ("powerpc32: rewrite csum_partial_copy_generic() based on copy_tofrom_user()")
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
|
|
Switch the setting of psl_fir_cntl from debug to production
environment recommended value. It mostly affects the PSL behavior when
an error is raised in psl_fir1/2.
Tested with cxlflash.
Signed-off-by: Frederic Barrat <[email protected]>
Reviewed-by: Uma Krishnan <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
|
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git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
User visible fixes:
- Fix the lookup for a kernel module in 'perf probe', fixing for instance, the
erroneous return of "[raid10]" when looking for "[raid1]" (Konstantin Khlebnikov)
- Disable counters in a group before reading them in 'perf stat', to avoid skew (Mark Rutland)
- Fix adding probes to function aliases in systems using kaslr (Masami Hiramatsu)
- Trip libtraceevent trace_seq buffers, removing unnecessary memory usage that could
bring a system using tracepoint events with 'perf top' to a crawl, as the trace_seq
buffers start at a whooping 4 KB, which is very rarely used in perf's usecases,
so realloc it to the really used space as a last measure after using libtraceevent
functions to format the fields of tracepoint events (Arnaldo Carvalho de Melo)
- Fix 'perf probe' location when using DWARF on ppc64le (Ravi Bangoria)
- Allow specifying signedness casts to a 'perf probe' variable, to shorten
the number of steps to see signed values that otherwise would always appear
as hex values (Naohiro Aota)
Documentation fixes:
- Add 'bpf-output' field to 'perf script' usage message (Brendan Gregg)
Infrastructure fixes:
- Sync kernel header files: cpufeatures.h, {disabled,required}-features.h,
bpf.h and vmx.h, so that we get a clean build, without warnings about files
being different from the kernel counterparts.
A verification of the need or desirability of changes in tools/ based on what
was done in the kernel changesets was made and documented in the respective
file sync changesets (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
|
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This reverts commit 874f9c7da9a4acbc1b9e12ca722579fb50e4d142.
Geert Uytterhoeven reports:
"This change seems to have an (unintendent?) side-effect.
Before, pr_*() calls without a trailing newline characters would be
printed with a newline character appended, both on the console and in
the output of the dmesg command.
After this commit, no new line character is appended, and the output
of the next pr_*() call of the same type may be appended, like in:
- Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000
- Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)
+ Truncating RAM at 0x0000000040000000-0x00000000c0000000 to -0x0000000070000000Ignoring RAM at 0x0000000200000000-0x0000000240000000 (!CONFIG_HIGHMEM)"
Joe Perches says:
"No, that is not intentional.
The newline handling code inside vprintk_emit is a bit involved and
for now I suggest a revert until this has all the same behavior as
earlier"
Reported-by: Geert Uytterhoeven <[email protected]>
Requested-by: Joe Perches <[email protected]>
Cc: Andrew Morton <[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 tracing fix from Steven Rostedt:
"Fix tick_stop tracepoint symbols for user export.
Luiz Capitulino noticed that the tick_stop tracepoint wasn't being
parsed properly by the tracing user space tools.
This was due to the TRACE_DEFINE_ENUM() being set to a define, when it
should have been set to the enum itself. The define was of the MASK
that used the BIT to shift. The BIT was the enum and by adding that,
everything gets converted nicely. The MASK is still kept just in case
it gets converted to an enum in the future"
* tag 'trace-v4.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix tick_stop tracepoint symbols for user export
|
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git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux
Pull gcc plugin improvements from Kees Cook:
"Several fixes/improvements for the gcc plugin infrastructure:
- fix a problem with gcc plugins interfering with cc-option tests.
- abort more gracefully when gcc plugin headers or compiler support
is missing.
- improve the gcc plugin rule generation to be more dynamic, pass
arguments, and build from subdirectories"
* tag 'gcc-plugin-infrastructure-v4.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
gcc-plugins: Add support for plugin subdirectories
gcc-plugins: Automate make rule generation
gcc-plugins: Add support for passing plugin arguments
gcc-plugins: abort builds cleanly when not supported
kbuild: no gcc-plugins during cc-option tests
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git://git.infradead.org/users/dvhart/linux-platform-drivers-x86
Pull x86 platform driver update from Darren Hart:
"dell-wmi: ignore battery remove/insert event"
* tag 'platform-drivers-x86-v4.8-3' of git://git.infradead.org/users/dvhart/linux-platform-drivers-x86:
dell-wmi: Ignore WMI event 0xe00e
|
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Pull drm fixes from Dave Airlie:
"This contains a bunch of amdgpu fixes, and some i915 regression fixes.
It also contains some fixes for an older regression with some EDID
changes and some 6bpc panels.
Then there are the lockdep, cirrus and rcar-du regression fixes from
this window"
* tag 'drm-fixes-for-4.8-rc2' of git://people.freedesktop.org/~airlied/linux:
drm/cirrus: Fix NULL pointer dereference when registering the fbdev
drm/edid: Set 8 bpc color depth for displays with "DFP 1.x compliant TMDS".
drm/i915/dp: Revert "drm/i915/dp: fall back to 18 bpp when sink capability is unknown"
drm/edid: Add 6 bpc quirk for display AEO model 0.
drm: Paper over locking inversion after registration rework
drm: rcar-du: Link HDMI encoder with bridge
drm/ttm: Wait for a BO to become idle before unbinding it from GTT
drm/i915/fbdev: Check for the framebuffer before use
drm/amdgpu: update golden setting of polaris10
drm/amdgpu: update golden setting of stoney
drm/amdgpu: update golden setting of polaris11
drm/amdgpu: update golden setting of carrizo
drm/amdgpu: update golden setting of iceland
drm/amd/amdgpu: change pptable output format from ASCII to binary
drm/amdgpu/ci: add mullins to default case for smc ucode
drm/amdgpu/gmc7: add missing mullins case
drm/i915: Never fully mask the the EI up rps interrupt on SNB/IVB
drm/i915: Wait up to 3ms for the pcu to ack the cdclk change request on SKL
|
|
Commit b195d5e2bffd ("ipr: Wait to do async scan until scsi host is
initialized") fixed async scan for ipr, but broke sync scan for ipr.
This fixes sync scan back up.
Signed-off-by: Brian King <[email protected]>
Reported-and-tested-by: Michael Ellerman <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
To distinguish non-slab pages charged to kmemcg we mark them PageKmemcg,
which sets page->_mapcount to -512. Currently, we set/clear PageKmemcg
in __alloc_pages_nodemask()/free_pages_prepare() for any page allocated
with __GFP_ACCOUNT, including those that aren't actually charged to any
cgroup, i.e. allocated from the root cgroup context. To avoid overhead
in case cgroups are not used, we only do that if memcg_kmem_enabled() is
true. The latter is set iff there are kmem-enabled memory cgroups
(online or offline). The root cgroup is not considered kmem-enabled.
As a result, if a page is allocated with __GFP_ACCOUNT for the root
cgroup when there are kmem-enabled memory cgroups and is freed after all
kmem-enabled memory cgroups were removed, e.g.
# no memory cgroups has been created yet, create one
mkdir /sys/fs/cgroup/memory/test
# run something allocating pages with __GFP_ACCOUNT, e.g.
# a program using pipe
dmesg | tail
# remove the memory cgroup
rmdir /sys/fs/cgroup/memory/test
we'll get bad page state bug complaining about page->_mapcount != -1:
BUG: Bad page state in process swapper/0 pfn:1fd945c
page:ffffea007f651700 count:0 mapcount:-511 mapping: (null) index:0x0
flags: 0x1000000000000000()
To avoid that, let's mark with PageKmemcg only those pages that are
actually charged to and hence pin a non-root memory cgroup.
Fixes: 4949148ad433 ("mm: charge/uncharge kmemcg from generic page allocator paths")
Reported-and-tested-by: Eric Dumazet <[email protected]>
Signed-off-by: Vladimir Davydov <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
|
|
pathbase is the base inode; set it to 0 if we've got no path.
Coverity-id: 146348
Signed-off-by: Ilya Dryomov <[email protected]>
Reviewed-by: Alex Elder <[email protected]>
|
|
ceph_file_layout::pool_id is now s64. rbd_add_get_pool_id() and
ceph_pg_poolid_by_name() both return an int, so it's bogus anyway.
Signed-off-by: Ilya Dryomov <[email protected]>
Reviewed-by: Alex Elder <[email protected]>
|
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Powerpc has Global Entry Point and Local Entry Point for functions. LEP
catches call from both the GEP and the LEP. Symbol table of ELF contains
GEP and Offset from which we can calculate LEP, but debuginfo does not
have LEP info.
Currently, perf prioritize symbol table over dwarf to probe on LEP for
ppc64le. But when user tries to probe with function parameter, we fall
back to using dwarf(i.e. GEP) and when function called via LEP, probe
will never hit.
For example:
$ objdump -d vmlinux
...
do_sys_open():
c0000000002eb4a0: e8 00 4c 3c addis r2,r12,232
c0000000002eb4a4: 60 00 42 38 addi r2,r2,96
c0000000002eb4a8: a6 02 08 7c mflr r0
c0000000002eb4ac: d0 ff 41 fb std r26,-48(r1)
$ sudo ./perf probe do_sys_open
$ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/do_sys_open _text+3060904
$ sudo ./perf probe 'do_sys_open filename:string'
$ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string
For second case, perf probed on GEP. So when function will be called via
LEP, probe won't hit.
$ sudo ./perf record -a -e probe:do_sys_open ls
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.195 MB perf.data ]
To resolve this issue, let's not prioritize symbol table, let perf
decide what it wants to use. Perf is already converting GEP to LEP when
it uses symbol table. When perf uses debuginfo, let it find LEP offset
form symbol table. This way we fall back to probe on LEP for all cases.
After patch:
$ sudo ./perf probe 'do_sys_open filename:string'
$ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string
$ sudo ./perf record -a -e probe:do_sys_open ls
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.197 MB perf.data (11 samples) ]
Signed-off-by: Ravi Bangoria <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/1470723805-5081-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Instead of inline code, introduce function to post process kernel
probe trace events.
Signed-off-by: Ravi Bangoria <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ananth N Mavinakayanahalli <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Naveen N. Rao <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/1470723805-5081-1-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
Due to:
1e61f78baf89 ("x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated")
No changes to tools using those headers (tools/arch/x86/lib/mem{set,cpu}_64.S)
seems necessary.
Detected by the tools build header drift checker:
$ make -C tools/perf O=/tmp/build/perf
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
GEN /tmp/build/perf/common-cmds.h
Warning: tools/arch/x86/include/asm/disabled-features.h differs from kernel
Warning: tools/arch/x86/include/asm/required-features.h differs from kernel
Warning: tools/arch/x86/include/asm/cpufeatures.h differs from kernel
CC /tmp/build/perf/util/probe-finder.o
CC /tmp/build/perf/builtin-help.o
<SNIP>
^C$
Cc: Adrian Hunter <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
|
|
The way we're using kernel headers in tools/ now, with a copy that is
made to the same path prefixed by "tools/" plus checking if that copy
got stale, i.e. if the kernel counterpart changed, helps in keeping
track with new features that may be useful for tools to exploit.
For instance, looking at all the changes to bpf.h since it was last
copied to tools/include brings this to toolers' attention:
Need to investigate this one to check how to run a program via perf, setting up
a BPF event, that will take advantage of the way perf already calls clang/LLVM,
sets up the event and runs the workload in a single command line, helping in
debugging such semi cooperative programs:
96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
This one needs further investigation about using the feature it improves
in 'perf trace' to do some tcpdumpin' mixed with syscalls, tracepoints,
probe points, callgraphs, etc:
555c8a8623a3 ("bpf: avoid stack copy and use skb ctx for event output")
Add tracing just packets that are related to some container to that mix:
4a482f34afcc ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
4ed8ec521ed5 ("cgroup: bpf: Add BPF_MAP_TYPE_CGROUP_ARRAY")
Definetely needs to have example programs accessing task_struct from a bpf proggie
started from 'perf trace':
606274c5abd8 ("bpf: introduce bpf_get_current_task() helper")
Core networking related, XDP:
6ce96ca348a9 ("bpf: add XDP_TX xdp_action for direct forwarding")
6a773a15a1e8 ("bpf: add XDP prog type for early driver filter")
13c5c240f789 ("bpf: add bpf_get_hash_recalc helper")
d2485c4242a8 ("bpf: add bpf_skb_change_type helper")
6578171a7ff0 ("bpf: add bpf_skb_change_proto helper")
Changes detected by the tools build system:
$ make -C tools/perf O=/tmp/build/perf install-bin
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
Warning: tools/include/uapi/linux/bpf.h differs from kernel
INSTALL GTK UI
CC /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
<SNIP>
$
Cc: Adrian Hunter <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Brenden Blanco <[email protected]>
Cc: Daniel Borkmann <[email protected]>
Cc: David Ahern <[email protected]>
Cc: David S. Miller <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Martin KaFai Lau <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Sargun Dhillon <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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There were changes related to the deprecation of the "pcommit"
instruction:
fd1d961dd681 ("x86/insn: remove pcommit")
dfa169bbee00 ("Revert "KVM: x86: add pcommit support"")
No need to update anything in the tools, as "pcommit" wasn't being
listed on the VMX_EXIT_REASONS in the tools/perf/arch/x86/util/kvm-stat.c
file.
Just grab fresh copies of these files to silence the file cache
coherency detector:
$ make -C tools/perf O=/tmp/build/perf install-bin
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
Warning: tools/arch/x86/include/asm/cpufeatures.h differs from kernel
Warning: tools/arch/x86/include/uapi/asm/vmx.h differs from kernel
INSTALL GTK UI
<SNIP>
#
Cc: Adrian Hunter <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Ross Zwisler <[email protected]>
Cc: Wang Nan <[email protected]>
Cc: Xiao Guangrong <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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The 'perf probe' tool detects a variable's type and use the detected
type to add a new probe. Then, kprobes prints its variable in
hexadecimal format if the variable is unsigned and prints in decimal if
it is signed.
We sometimes want to see unsigned variable in decimal format (i.e.
sector_t or size_t). In that case, we need to investigate the variable's
size manually to specify just signedness.
This patch add signedness casting support. By specifying "s" or "u" as a
type, perf-probe will investigate variable size as usual and use the
specified signedness.
E.g. without this:
$ perf probe -a 'submit_bio bio->bi_iter.bi_sector'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
$ cat trace_pipe|head
dbench-9692 [003] d..1 971.096633: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d00
dbench-9692 [003] d..1 971.096685: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x1a3d80
dbench-9692 [003] d..1 971.096687: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d80
...
// need to investigate the variable size
$ perf probe -a 'submit_bio bio->bi_iter.bi_sector:s64'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s64)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
With this:
// just use "s" to cast its signedness
$ perf probe -v -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
$ cat trace_pipe|head
dbench-9689 [001] d..1 1212.391237: submit_bio: (submit_bio+0x0/0x140) bi_sector=128
dbench-9689 [001] d..1 1212.391252: submit_bio: (submit_bio+0x0/0x140) bi_sector=131072
dbench-9697 [006] d..1 1212.398611: submit_bio: (submit_bio+0x0/0x140) bi_sector=30208
This commit also update perf-probe.txt to describe "types". Most parts
are based on existing documentation: Documentation/trace/kprobetrace.txt
Committer note:
Testing using 'perf trace':
# perf probe -a 'submit_bio bio->bi_iter.bi_sector'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
# trace --no-syscalls --ev probe:submit_bio
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=0xc133c0)
3181.861 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffb8)
3181.881 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc0)
3184.488 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc8)
<SNIP>
4717.927 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7a88)
4717.970 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7880)
^C[root@jouet ~]#
Now, using this new feature:
[root@jouet ~]# perf probe -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
[root@jouet ~]# trace --no-syscalls --ev probe:submit_bio
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145704)
0.017 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145712)
0.019 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145720)
2.567 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145728)
5631.919 probe:submit_bio:(ffffffffac3aee00) bi_sector=0)
5631.941 probe:submit_bio:(ffffffffac3aee00) bi_sector=8)
5631.945 probe:submit_bio:(ffffffffac3aee00) bi_sector=16)
5631.948 probe:submit_bio:(ffffffffac3aee00) bi_sector=24)
^C#
With callchains:
# trace --no-syscalls --ev probe:submit_bio/max-stack=10/
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662544)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
0.023 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662552)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
0.027 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662560)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
2.593 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662568)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
journal_submit_commit_record+0xa82001ac ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa82012e8 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
^C#
Signed-off-by: Naohiro Aota <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Hemant Kumar <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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The symbols used in the tick_stop tracepoint were not being converted
properly into integers in the trace_stop format file. Instead we had this:
print fmt: "success=%d dependency=%s", REC->success,
__print_symbolic(REC->dependency, { 0, "NONE" },
{ (1 << TICK_DEP_BIT_POSIX_TIMER), "POSIX_TIMER" },
{ (1 << TICK_DEP_BIT_PERF_EVENTS), "PERF_EVENTS" },
{ (1 << TICK_DEP_BIT_SCHED), "SCHED" },
{ (1 << TICK_DEP_BIT_CLOCK_UNSTABLE), "CLOCK_UNSTABLE" })
User space tools have no idea how to parse "TICK_DEP_BIT_SCHED" or the other
symbols used to do the bit shifting. The reason is that the conversion was
done with using the TICK_DEP_MASK_* symbols which are just macros that
convert to the BIT shift itself (with the exception of NONE, which was
converted properly, because it doesn't use bits, and is defined as zero).
The TICK_DEP_BIT_* needs to be denoted by TRACE_DEFINE_ENUM() in order to
have this properly converted for user space tools to parse this event.
Cc: [email protected]
Cc: Frederic Weisbecker <[email protected]>
Fixes: e6e6cc22e067 ("nohz: Use enum code for tick stop failure tracing message")
Reported-by: Luiz Capitulino <[email protected]>
Tested-by: Luiz Capitulino <[email protected]>
Signed-off-by: Steven Rostedt <[email protected]>
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When we don't have a tracee (i.e. we're attaching to a task or CPU),
counters can still be running after our workload finishes, and can still
be running as we read their values. As we read events one-by-one, there
can be arbitrary skew between values of events, even within a group.
This means that ratios within an event group are not reliable.
This skew can be seen if measuring a group of identical events, e.g:
# perf stat -a -C0 -e '{cycles,cycles}' sleep 1
To avoid this, we must stop groups from counting before we read the
values of any constituent events. This patch adds and makes use of a new
disable_counters() helper, which disables group leaders (and thus each
group as a whole). This mirrors the use of enable_counters() for
starting event groups in the absence of a tracee.
Closing a group leader splits the group, and without a disabled group
leader the newly split events will begin counting. Thus to ensure counts
are reliable we must defer closing group leaders until all counts have
been read. To do so this patch removes the event closing logic from the
read_counters() helper, explicitly closes the events using
perf_evlist__close(), which also aids legibility.
Signed-off-by: Mark Rutland <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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If module is "module" then dso->short_name is "[module]". Substring
comparing is't enough: "raid10" matches to "[raid1]". This patch also
checks terminating zero in module name.
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Acked-by: Masami Hiramatsu <[email protected]>
Link: http://lkml.kernel.org/r/147039975648.715620.12985971832789032159.stgit@buzz
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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Adjust map->reloc offset for the unmapped address when finding
alternative symbol address from map, because KASLR can relocate the
kernel symbol address.
The same adjustment has been done when finding appropriate kernel symbol
address from map which was introduced by commit f90acac75713 ("perf
probe: Find given address from offline dwarf")
Reported-by: Arnaldo Carvalho de Melo <[email protected]>
Signed-off-by: Masami Hiramatsu <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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When we use libtraceevent to format trace event fields into printable
strings to use in hist entries it is important to trim it from the
default 4 KiB it starts with to what is really used, to reduce the
memory footprint, so use realloc(seq.buffer, seq.len + 1) when returning
the seq.buffer formatted with the fields contents.
Reported-and-Tested-by: Wang Nan <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Namhyung Kim <[email protected]>
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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This adds the 'bpf-output' field to the perf script usage message, and docs.
Signed-off-by: Brendan Gregg <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Wang Nan <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
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The recent commit 599d0c954f91 ("mm, vmscan: move LRU lists to node"),
changed memory management code so that show_mem() is no longer safe to
call prior to setup_per_cpu_pageset(), as pgdat->per_cpu_nodestats will
still be NULL. This causes an oops on metag due to the call to
show_mem() from mem_init():
node_page_state_snapshot(...) + 0x48
pgdat_reclaimable(struct pglist_data * pgdat = 0x402517a0)
show_free_areas(unsigned int filter = 0) + 0x2cc
show_mem(unsigned int filter = 0) + 0x18
mem_init()
mm_init()
start_kernel() + 0x204
This wasn't a problem before with zone_reclaimable() as zone_pcp_init()
was already setting zone->pageset to &boot_pageset, via setup_arch() and
paging_init(), which happens before mm_init():
zone_pcp_init(...)
free_area_init_core(...) + 0x138
free_area_init_node(int nid = 0, ...) + 0x1a0
free_area_init_nodes(...) + 0x440
paging_init(unsigned long mem_end = 0x4fe00000) + 0x378
setup_arch(char ** cmdline_p = 0x4024e038) + 0x2b8
start_kernel() + 0x54
No other arches appear to call show_mem() during boot, and it doesn't
really add much value to the log, so lets just drop it from mem_init().
Signed-off-by: James Hogan <[email protected]>
Acked-by: Mel Gorman <[email protected]>
Cc: [email protected]
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There only ever have been two host implementations of the old
s390-virtio (pre-ccw) transport: the experimental kuli userspace,
and qemu. As qemu switched its default to ccw with 2.4 (with most
users having used ccw well before that) and removed the old transport
entirely in 2.6, s390-virtio probably hasn't been in active use for
quite some time and is therefore likely to bitrot.
Let's start the slow march towards removing the code by deprecating
it.
Note that this also deprecates the early virtio console code, which
has been causing trouble in the guest without being wired up in any
relevant hypervisor code.
Acked-by: Christian Borntraeger <[email protected]>
Reviewed-by: Dong Jia Shi <[email protected]>
Reviewed-by: Sascha Silbe <[email protected]>
Signed-off-by: Cornelia Huck <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
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