15 Dec, 2011
1 commit
-
Make cputime_t and cputime64_t nocast to enable sparse checking to
detect incorrect use of cputime. Drop the cputime macros for simple
scalar operations. The conversion macros are still needed.Signed-off-by: Martin Schwidefsky
26 Oct, 2011
1 commit
-
* 'core-locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (27 commits)
rtmutex: Add missing rcu_read_unlock() in debug_rt_mutex_print_deadlock()
lockdep: Comment all warnings
lib: atomic64: Change the type of local lock to raw_spinlock_t
locking, lib/atomic64: Annotate atomic64_lock::lock as raw
locking, x86, iommu: Annotate qi->q_lock as raw
locking, x86, iommu: Annotate irq_2_ir_lock as raw
locking, x86, iommu: Annotate iommu->register_lock as raw
locking, dma, ipu: Annotate bank_lock as raw
locking, ARM: Annotate low level hw locks as raw
locking, drivers/dca: Annotate dca_lock as raw
locking, powerpc: Annotate uic->lock as raw
locking, x86: mce: Annotate cmci_discover_lock as raw
locking, ACPI: Annotate c3_lock as raw
locking, oprofile: Annotate oprofilefs lock as raw
locking, video: Annotate vga console lock as raw
locking, latencytop: Annotate latency_lock as raw
locking, timer_stats: Annotate table_lock as raw
locking, rwsem: Annotate inner lock as raw
locking, semaphores: Annotate inner lock as raw
locking, sched: Annotate thread_group_cputimer as raw
...Fix up conflicts in kernel/posix-cpu-timers.c manually: making
cputimer->cputime a raw lock conflicted with the ABBA fix in commit
bcd5cff7216f ("cputimer: Cure lock inversion").
18 Oct, 2011
1 commit
-
There's a lock inversion between the cputimer->lock and rq->lock;
notably the two callchains involved are:update_rlimit_cpu()
sighand->siglock
set_process_cpu_timer()
cpu_timer_sample_group()
thread_group_cputimer()
cputimer->lock
thread_group_cputime()
task_sched_runtime()
->pi_lock
rq->lockscheduler_tick()
rq->lock
task_tick_fair()
update_curr()
account_group_exec()
cputimer->lockWhere the first one is enabling a CLOCK_PROCESS_CPUTIME_ID timer, and
the second one is keeping up-to-date.This problem was introduced by e8abccb7193 ("posix-cpu-timers: Cure
SMP accounting oddities").Cure the problem by removing the cputimer->lock and rq->lock nesting,
this leaves concurrent enablers doing duplicate work, but the time
wasted should be on the same order otherwise wasted spinning on the
lock and the greater-than assignment filter should ensure we preserve
monotonicity.Reported-by: Dave Jones
Reported-by: Simon Kirby
Signed-off-by: Peter Zijlstra
Cc: stable@kernel.org
Cc: Linus Torvalds
Cc: Martin Schwidefsky
Link: http://lkml.kernel.org/r/1318928713.21167.4.camel@twins
Signed-off-by: Thomas Gleixner
30 Sep, 2011
1 commit
-
David reported:
Attached below is a watered-down version of rt/tst-cpuclock2.c from
GLIBC. Just build it with "gcc -o test test.c -lpthread -lrt" or
similar.Run it several times, and you will see cases where the main thread
will measure a process clock difference before and after the nanosleep
which is smaller than the cpu-burner thread's individual thread clock
difference. This doesn't make any sense since the cpu-burner thread
is part of the top-level process's thread group.I've reproduced this on both x86-64 and sparc64 (using both 32-bit and
64-bit binaries).For example:
[davem@boricha build-x86_64-linux]$ ./test
process: before(0.001221967) after(0.498624371) diff(497402404)
thread: before(0.000081692) after(0.498316431) diff(498234739)
self: before(0.001223521) after(0.001240219) diff(16698)
[davem@boricha build-x86_64-linux]$The diff of 'process' should always be >= the diff of 'thread'.
I make sure to wrap the 'thread' clock measurements the most tightly
around the nanosleep() call, and that the 'process' clock measurements
are the outer-most ones.---
#include
#include
#include
#include
#include
#include
#include
#includestatic pthread_barrier_t barrier;
static void *chew_cpu(void *arg)
{
pthread_barrier_wait(&barrier);
while (1)
__asm__ __volatile__("" : : : "memory");
return NULL;
}int main(void)
{
clockid_t process_clock, my_thread_clock, th_clock;
struct timespec process_before, process_after;
struct timespec me_before, me_after;
struct timespec th_before, th_after;
struct timespec sleeptime;
unsigned long diff;
pthread_t th;
int err;err = clock_getcpuclockid(0, &process_clock);
if (err)
return 1;err = pthread_getcpuclockid(pthread_self(), &my_thread_clock);
if (err)
return 1;pthread_barrier_init(&barrier, NULL, 2);
err = pthread_create(&th, NULL, chew_cpu, NULL);
if (err)
return 1;err = pthread_getcpuclockid(th, &th_clock);
if (err)
return 1;pthread_barrier_wait(&barrier);
err = clock_gettime(process_clock, &process_before);
if (err)
return 1;err = clock_gettime(my_thread_clock, &me_before);
if (err)
return 1;err = clock_gettime(th_clock, &th_before);
if (err)
return 1;sleeptime.tv_sec = 0;
sleeptime.tv_nsec = 500000000;
nanosleep(&sleeptime, NULL);err = clock_gettime(th_clock, &th_after);
if (err)
return 1;err = clock_gettime(my_thread_clock, &me_after);
if (err)
return 1;err = clock_gettime(process_clock, &process_after);
if (err)
return 1;diff = process_after.tv_nsec - process_before.tv_nsec;
printf("process: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n",
process_before.tv_sec, process_before.tv_nsec,
process_after.tv_sec, process_after.tv_nsec, diff);
diff = th_after.tv_nsec - th_before.tv_nsec;
printf("thread: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n",
th_before.tv_sec, th_before.tv_nsec,
th_after.tv_sec, th_after.tv_nsec, diff);
diff = me_after.tv_nsec - me_before.tv_nsec;
printf("self: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n",
me_before.tv_sec, me_before.tv_nsec,
me_after.tv_sec, me_after.tv_nsec, diff);return 0;
}This is due to us using p->se.sum_exec_runtime in
thread_group_cputime() where we iterate the thread group and sum all
data. This does not take time since the last schedule operation (tick
or otherwise) into account. We can cure this by using
task_sched_runtime() at the cost of having to take locks.This also means we can (and must) do away with
thread_group_sched_runtime() since the modified thread_group_cputime()
is now more accurate and would deadlock when called from
thread_group_sched_runtime().Aside of that it makes the function safe on 32 bit systems. The old
code added t->se.sum_exec_runtime unprotected. sum_exec_runtime is a
64bit value and could be changed on another cpu at the same time.Reported-by: David Miller
Signed-off-by: Peter Zijlstra
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/1314874459.7945.22.camel@twins
Tested-by: David Miller
Signed-off-by: Thomas Gleixner
13 Sep, 2011
1 commit
-
The thread_group_cputimer lock can be taken in atomic context and therefore
cannot be preempted on -rt - annotate it.In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.Signed-off-by: Thomas Gleixner
Signed-off-by: Ingo Molnar
23 May, 2011
1 commit
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Instead of iterating over all possible timer bases avoid it by marking
the active bases in the cpu base.Signed-off-by: Thomas Gleixner
Reviewed-by: Peter Zijlstra
31 Mar, 2011
1 commit
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Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: Lucas De Marchi
02 Feb, 2011
7 commits
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Rename register_posix_clock() to posix_timers_register_clock(). That's
what the function really does. As a side effect this cleans up the
posix_clock namespace for the upcoming dynamic posix_clock
infrastructure.Signed-off-by: Thomas Gleixner
Tested-by: Richard Cochran
Cc: John Stultz
LKML-Reference: -
All functions are accessed via clock_posix_cpu now. So make them static.
Signed-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Richard Cochran
LKML-Reference: -
Use the new kclock decoding function in clock_settime and cleanup all
kclocks which use the default functions. Rename the misnomed
common_clock_set() to posix_clock_realtime_set().Signed-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Richard Cochran
LKML-Reference: -
CLOCK_THREAD_CPUTIME_ID implements stub functions for nanosleep and
nanosleep_restart, which return -EINVAL. That return value is
wrong. The correct return value is -ENOTSUP.Remove the stubs and let the new dispatch code return the correct
error code.Signed-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Richard Cochran
LKML-Reference: -
posix timers still use the legacy arg0-arg3 members of
restart_block. Use restart_block.nanosleep insteadSigned-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Richard Cochran
LKML-Reference: -
The CLOCK_DISPATCH() macro is a horrible magic. We call common
functions if a function pointer is not set. That's just backwards.To support dynamic file decriptor based clocks we need to cleanup that
dispatch logic.Create a k_clock struct clock_posix_cpu which has all the
posix-cpu-timer functions filled in. After the cleanup the functions
can be made static.Signed-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Richard Cochran
LKML-Reference: -
Cosmetic. No functional change
Signed-off-by: Thomas Gleixner
Acked-by: John Stultz
Tested-by: Richard Cochran
LKML-Reference:
10 Nov, 2010
1 commit
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Commit 4221a9918e38b7494cee341dda7b7b4bb8c04bde "Add RCU check for
find_task_by_vpid()" introduced rcu_lockdep_assert to find_task_by_pid_ns.
Add rcu_read_lock/rcu_read_unlock to call find_task_by_vpid.Tetsuo Handa wrote:
| Quoting from one of posts in that thead
| http://kerneltrap.org/mailarchive/linux-kernel/2010/2/8/4536388
|
|| Usually tasklist gives enough protection, but if copy_process() fails
|| it calls free_pid() lockless and does call_rcu(delayed_put_pid().
|| This means, without rcu lock find_pid_ns() can't scan the hash table
|| safely.Thomas Gleixner wrote:
| We can remove the tasklist_lock while at it. rcu_read_lock is enough.Patch also replaces thread_group_leader with has_group_leader_pid
in accordance to comment by Oleg Nesterov:| ... thread_group_leader() check is not relaible without
| tasklist. If we race with de_thread() find_task_by_vpid() can find
| the new leader before it updates its ->group_leader.
|
| perhaps it makes sense to change posix_cpu_timer_create() to use
| has_group_leader_pid() instead, just to make this code not look racy
| and avoid adding new problems.Signed-off-by: Sergey Senozhatsky
Cc: Peter Zijlstra
Cc: Stanislaw Gruszka
Reviewed-by: Oleg Nesterov
LKML-Reference:
Signed-off-by: Thomas Gleixner
11 Aug, 2010
1 commit
-
* 'writable_limits' of git://decibel.fi.muni.cz/~xslaby/linux:
unistd: add __NR_prlimit64 syscall numbers
rlimits: implement prlimit64 syscall
rlimits: switch more rlimit syscalls to do_prlimit
rlimits: redo do_setrlimit to more generic do_prlimit
rlimits: add rlimit64 structure
rlimits: do security check under task_lock
rlimits: allow setrlimit to non-current tasks
rlimits: split sys_setrlimit
rlimits: selinux, do rlimits changes under task_lock
rlimits: make sure ->rlim_max never grows in sys_setrlimit
rlimits: add task_struct to update_rlimit_cpu
rlimits: security, add task_struct to setrlimitFix up various system call number conflicts. We not only added fanotify
system calls in the meantime, but asm-generic/unistd.h added a wait4
along with a range of reserved per-architecture system calls.
16 Jul, 2010
1 commit
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Add task_struct as a parameter to update_rlimit_cpu to be able to set
rlimit_cpu of different task than current.Signed-off-by: Jiri Slaby
Acked-by: James Morris
18 Jun, 2010
3 commits
-
fastpath_timer_check()->thread_group_cputimer() is racy and
unneeded.It is racy because another thread can clear ->running before
thread_group_cputimer() takes cputimer->lock. In this case
thread_group_cputimer() will set ->running = true again and call
thread_group_cputime(). But since we do not hold tasklist or
siglock, we can race with fork/exit and copy the wrong results
into cputimer->cputime.It is unneeded because if ->running == true we can just use
the numbers in cputimer->cputime we already have.Change fastpath_timer_check() to copy cputimer->cputime into
the local variable under cputimer->lock. We do not re-check
->running under cputimer->lock, run_posix_cpu_timers() does
this check later.Note: we can add more optimizations on top of this change.
Signed-off-by: Oleg Nesterov
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
run_posix_cpu_timers() doesn't work if current has already passed
exit_notify(). This was needed to prevent the races with do_wait().Since ea6d290c ->signal is always valid and can't go away. We can
remove the "tsk->exit_state == 0" in fastpath_timer_check() and
convert run_posix_cpu_timers() to use lock_task_sighand().Note: it makes sense to take group_leader's sighand instead, the
sub-thread still uses CPU after release_task(). But we need more
changes to do this.Signed-off-by: Oleg Nesterov
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar -
thread_group_cputime() looks as if it is rcu-safe, but in fact this
was wrong until ea6d290c which pins task->signal to task_struct.
It checks ->sighand != NULL under rcu, but this can't help if ->signal
can go away. Fortunately the caller either holds ->siglock, or it is
fastpath_timer_check() which uses current and checks exit_state == 0.- Since ea6d290c commit tsk->signal is stable, we can read it first
and avoid the initialization from INIT_CPUTIME.- Even if tsk->signal is always valid, we still have to check it
is safe to use next_thread() under rcu_read_lock(). Currently
the code checks ->sighand != NULL, change it to use pid_alive()
which is commonly used to ensure the task wasn't unhashed before
we take rcu_read_lock().Add the comment to explain this check.
- Change the main loop to use the while_each_thread() helper.
Signed-off-by: Oleg Nesterov
Signed-off-by: Peter Zijlstra
LKML-Reference:
Signed-off-by: Ingo Molnar
28 May, 2010
1 commit
-
Preparation to make task->signal immutable, no functional changes.
posix-cpu-timers.c checks task->signal != NULL to ensure this task is
alive and didn't pass __exit_signal(). This is correct but we are going
to change the lifetime rules for ->signal and never reset this pointer.Change the code to check ->sighand instead, it doesn't matter which
pointer we check under tasklist, they both are cleared simultaneously.As Roland pointed out, some of these changes are not strictly needed and
probably it makes sense to revert them later, when ->signal will be pinned
to task_struct. But this patch tries to ensure the subsequent changes in
fork/exit can't make any visible impact on posix cpu timers.Signed-off-by: Oleg Nesterov
Cc: Fenghua Yu
Acked-by: Roland McGrath
Cc: Stanislaw Gruszka
Cc: Tony Luck
Cc: Thomas Gleixner
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
10 May, 2010
2 commits
-
We can optimize and simplify things taking into account signal->cputimer
is always running when we have configured any process wide cpu timer.In check_process_timers(), we don't have to check if new updated value of
signal->cputime_expires is smaller, since we maintain new first expiration
time ({prof,virt,sched}_expires) in code flow and all other writes to
expiration cache are protected by sighand->siglock .Signed-off-by: Stanislaw Gruszka
Cc: Thomas Gleixner
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
Reason: Further posix_cpu_timer patches depend on mainline changes
Signed-off-by: Thomas Gleixner
27 Mar, 2010
1 commit
-
…el/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
time: Fix accumulation bug triggered by long delay.
posix-cpu-timers: Reset expire cache when no timer is running
timer stats: Fix del_timer_sync() and try_to_del_timer_sync()
clockevents: Sanitize min_delta_ns adjustment and prevent overflows
13 Mar, 2010
6 commits
-
Spread p->sighand->siglock locking scope to make sure that
fastpath_timer_check() never iterates over all threads. Without
locking there is small possibility that signal->cputimer will stop
running while we write values to signal->cputime_expires.Calling thread_group_cputime() from fastpath_timer_check() is not only
bad because it is slow, also it is racy with __exit_signal() which can
lead to invalid signal->{s,u}time values.Signed-off-by: Stanislaw Gruszka
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
When user sets up a timer without associated signal and process does
not use any other cpu timers and does not exit, tsk->signal->cputimer
is enabled and running forever.Avoid running the timer for no reason.
I used below program to check patch does not break current user space
visible behavior.#include
#include
#include
#include
#include
#include
#include
#includevoid consume_cpu(void)
{
int i = 0;
int count = 0;for(i=0; i< 30; i++) {
consume_cpu();
memset(&spec, 0, sizeof(spec));
assert(timer_gettime(tid, &spec) == 0);
printf("%lu.%09lu\n",
(unsigned long) spec.it_value.tv_sec,
(unsigned long) spec.it_value.tv_nsec);
}assert(timer_delete(tid) == 0);
return 0;
}Signed-off-by: Stanislaw Gruszka
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
According POSIX we need to correctly set old timer it_interval value when
user request that in timer_settime(). Tested using below program.#include
#include
#include
#include
#include
#include
#includeint main(void)
{
struct sigaction act;
struct sigevent evt = { };
timer_t tid;
struct itimerspec spec, u_spec, k_spec;evt.sigev_notify = SIGEV_SIGNAL;
evt.sigev_signo = SIGPROF;
assert(timer_create(CLOCK_PROCESS_CPUTIME_ID, &evt, &tid) == 0);spec.it_value.tv_sec = 1;
spec.it_value.tv_nsec = 2;
spec.it_interval.tv_sec = 3;
spec.it_interval.tv_nsec = 4;
u_spec = spec;
assert(timer_settime(tid, 0, &spec, NULL) == 0);spec.it_value.tv_sec = 5;
spec.it_value.tv_nsec = 6;
spec.it_interval.tv_sec = 7;
spec.it_interval.tv_nsec = 8;
assert(timer_settime(tid, 0, &spec, &k_spec) == 0);#define PRT(val) printf(#val ":\t%d/%d\n", (int) u_spec.val, (int) k_spec.val)
PRT(it_value.tv_sec);
PRT(it_value.tv_nsec);
PRT(it_interval.tv_sec);
PRT(it_interval.tv_nsec);return 0;
}Signed-off-by: Stanislaw Gruszka
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
Signed-off-by: Stanislaw Gruszka
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
Let always set signal->cputime_expires expiration cache when setting
new itimer, POSIX 1.b timer, and RLIMIT_CPU. Since we are
initializing prof_exp expiration cache during fork(), this allows to
remove "RLIMIT_CPU != inf" check from fastpath_timer_check() and do
some other cleanups.Checked against regression using test cases from:
http://marc.info/?l=linux-kernel&m=123749066504641&w=4
http://marc.info/?l=linux-kernel&m=123811277916642&w=2Signed-off-by: Stanislaw Gruszka
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Balbir Singh
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner -
When a process deletes cpu timer or a timer expires we do not clear
the expiration cache sig->cputimer_expires.As a result the fastpath_timer_check() which prevents us to loop over
all threads in case no timer is active is not working and we run the
slow path needlessly on every tick.Zero sig->cputimer_expires in stop_process_timers().
Signed-off-by: Stanislaw Gruszka
Cc: Ingo Molnar
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Cc: Hidetoshi Seto
Cc: Spencer Candland
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner
07 Mar, 2010
2 commits
-
Make sure compiler won't do weird things with limits. E.g. fetching them
twice may return 2 different values after writable limits are implemented.I.e. either use rlimit helpers added in commit 3e10e716abf3 ("resource:
add helpers for fetching rlimits") or ACCESS_ONCE if not applicable.Signed-off-by: Jiri Slaby
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: john stultz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Fetch rlimit (both hard and soft) values only once and work on them. It
removes many accesses through sig structure and makes the code cleaner.Mostly a preparation for writable resource limits support.
Signed-off-by: Jiri Slaby
Cc: Ingo Molnar
Cc: Peter Zijlstra
Cc: Thomas Gleixner
Cc: john stultz
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds
18 Nov, 2009
1 commit
-
We have already new_timer initialized to all-zeros hence in function
initializations are not needed. Document function expectation about
new_timer argument as well.Signed-off-by: Stanislaw Gruszka
Cc: johnstul@us.ibm.com
Cc: Oleg Nesterov
Cc: Peter Zijlstra
Signed-off-by: Andrew Morton
Signed-off-by: Thomas Gleixner
29 Aug, 2009
2 commits
-
Add tracepoints for all itimer variants: ITIMER_REAL, ITIMER_VIRTUAL
and ITIMER_PROF.[ tglx: Fixed comments and made the output more readable, parseable
and consistent. Replaced pid_vnr by pid_nr because the hrtimer
callback can happen in any namespace ]Signed-off-by: Xiao Guangrong
Cc: Steven Rostedt
Cc: Frederic Weisbecker
Cc: Mathieu Desnoyers
Cc: Anton Blanchard
Cc: Peter Zijlstra
Cc: KOSAKI Motohiro
Cc: Zhaolei
LKML-Reference:
Signed-off-by: Thomas Gleixner -
Merge reason: timer tracepoint patches depend on both branches
Signed-off-by: Thomas Gleixner
09 Aug, 2009
1 commit
-
When the process exits we don't have to run new cputimer nor
use running one (as it not accounts when tsk->exit_state != 0)
to get process CPU times. As there is only one thread we can
just use CPU times fields from task and signal structs.Signed-off-by: Stanislaw Gruszka
Cc: Peter Zijlstra
Cc: Roland McGrath
Cc: Vitaly Mayatskikh
Signed-off-by: Andrew Morton
Signed-off-by: Ingo Molnar
03 Aug, 2009
4 commits
-
For powerpc with CONFIG_VIRT_CPU_ACCOUNTING
jiffies_to_cputime(1) is not compile time constant and run time
calculations are quite expensive. To optimize we use
precomputed value. For all other architectures is is
preprocessor definition.Signed-off-by: Stanislaw Gruszka
Acked-by: Peter Zijlstra
Acked-by: Thomas Gleixner
Cc: Oleg Nesterov
Cc: Andrew Morton
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
LKML-Reference:
Signed-off-by: Ingo Molnar -
Don't update values in expiration cache when new ones are
equal. Add expire_le() and expire_gt() helpers to simplify the
code.Signed-off-by: Stanislaw Gruszka
Acked-by: Peter Zijlstra
Acked-by: Thomas Gleixner
Cc: Oleg Nesterov
Cc: Andrew Morton
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
LKML-Reference:
Signed-off-by: Ingo Molnar -
Measure ITIMER_PROF and ITIMER_VIRT timers interval error
between real ticks and requested by user. Take it into account
when scheduling next tick.This patch introduce possibility where time between two
consecutive tics is smaller then requested interval, it
preserve however dependency that n tick is generated not
earlier than n*interval time - counting from the beginning of
periodic signal generation.Signed-off-by: Stanislaw Gruszka
Acked-by: Peter Zijlstra
Acked-by: Thomas Gleixner
Cc: Oleg Nesterov
Cc: Andrew Morton
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
LKML-Reference:
Signed-off-by: Ingo Molnar -
Both cpu itimers have same data flow in the few places, this
patch make unification of code related with VIRT and PROF
itimers.Signed-off-by: Stanislaw Gruszka
Acked-by: Peter Zijlstra
Acked-by: Thomas Gleixner
Cc: Oleg Nesterov
Cc: Andrew Morton
Cc: Paul Mackerras
Cc: Benjamin Herrenschmidt
LKML-Reference:
Signed-off-by: Ingo Molnar