From 490dea45d00f01847ebebd007685d564aaf2cd98 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon, 24 Nov 2008 17:06:57 +0100
Subject: itimers: remove the per-cpu-ish-ness
Either we bounce once cacheline per cpu per tick, yielding n^2 bounces
or we just bounce a single..
Also, using per-cpu allocations for the thread-groups complicates the
per-cpu allocator in that its currently aimed to be a fixed sized
allocator and the only possible extention to that would be vmap based,
which is seriously constrained on 32 bit archs.
So making the per-cpu memory requirement depend on the number of
processes is an issue.
Lastly, it didn't deal with cpu-hotplug, although admittedly that might
be fixable.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/init_task.h | 6 ++++++
include/linux/sched.h | 29 ++++++++++++++++++-----------
2 files changed, 24 insertions(+), 11 deletions(-)
(limited to 'include/linux')
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 2f3c2d4ef73..ea0ea1a4c36 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -48,6 +48,12 @@ extern struct fs_struct init_fs;
.posix_timers = LIST_HEAD_INIT(sig.posix_timers), \
.cpu_timers = INIT_CPU_TIMERS(sig.cpu_timers), \
.rlim = INIT_RLIMITS, \
+ .cputime = { .totals = { \
+ .utime = cputime_zero, \
+ .stime = cputime_zero, \
+ .sum_exec_runtime = 0, \
+ .lock = __SPIN_LOCK_UNLOCKED(sig.cputime.totals.lock), \
+ }, }, \
}
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 4cae9b81a1f..c20943eabb4 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -450,6 +450,7 @@ struct task_cputime {
cputime_t utime;
cputime_t stime;
unsigned long long sum_exec_runtime;
+ spinlock_t lock;
};
/* Alternate field names when used to cache expirations. */
#define prof_exp stime
@@ -465,7 +466,7 @@ struct task_cputime {
* used for thread group CPU clock calculations.
*/
struct thread_group_cputime {
- struct task_cputime *totals;
+ struct task_cputime totals;
};
/*
@@ -2180,24 +2181,30 @@ static inline int spin_needbreak(spinlock_t *lock)
* Thread group CPU time accounting.
*/
-extern int thread_group_cputime_alloc(struct task_struct *);
-extern void thread_group_cputime(struct task_struct *, struct task_cputime *);
-
-static inline void thread_group_cputime_init(struct signal_struct *sig)
+static inline
+void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
{
- sig->cputime.totals = NULL;
+ struct task_cputime *totals = &tsk->signal->cputime.totals;
+ unsigned long flags;
+
+ spin_lock_irqsave(&totals->lock, flags);
+ *times = *totals;
+ spin_unlock_irqrestore(&totals->lock, flags);
}
-static inline int thread_group_cputime_clone_thread(struct task_struct *curr)
+static inline void thread_group_cputime_init(struct signal_struct *sig)
{
- if (curr->signal->cputime.totals)
- return 0;
- return thread_group_cputime_alloc(curr);
+ sig->cputime.totals = (struct task_cputime){
+ .utime = cputime_zero,
+ .stime = cputime_zero,
+ .sum_exec_runtime = 0,
+ };
+
+ spin_lock_init(&sig->cputime.totals.lock);
}
static inline void thread_group_cputime_free(struct signal_struct *sig)
{
- free_percpu(sig->cputime.totals);
}
/*
--
cgit v1.2.3-70-g09d2
From 6d612b0f943289856c6e8186c564cda922cd040e Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon, 12 Jan 2009 12:52:23 +0100
Subject: locking, hpet: annotate false positive warning
Alexander Beregalov reported that this warning is caused by the HPET code:
> hpet0: at MMIO 0xfed00000, IRQs 2, 8, 0
> hpet0: 3 comparators, 64-bit 14.318180 MHz counter
> ODEBUG: object is on stack, but not annotated
> ------------[ cut here ]------------
> WARNING: at lib/debugobjects.c:251 __debug_object_init+0x2a4/0x352()
> Bisected down to 26afe5f2fbf06ea0765aaa316640c4dd472310c0
> (x86: HPET_MSI Initialise per-cpu HPET timers)
The commit is fine - but the on-stack workqueue entry needs annotation.
Reported-and-bisected-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/hpet.c | 2 +-
include/linux/workqueue.h | 6 ++++++
2 files changed, 7 insertions(+), 1 deletion(-)
(limited to 'include/linux')
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index cd759ad9069..bb2e0f0975a 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -628,7 +628,7 @@ static int hpet_cpuhp_notify(struct notifier_block *n,
switch (action & 0xf) {
case CPU_ONLINE:
- INIT_DELAYED_WORK(&work.work, hpet_work);
+ INIT_DELAYED_WORK_ON_STACK(&work.work, hpet_work);
init_completion(&work.complete);
/* FIXME: add schedule_work_on() */
schedule_delayed_work_on(cpu, &work.work, 0);
diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index b36291130f2..47151c8495a 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -118,6 +118,12 @@ struct execute_work {
init_timer(&(_work)->timer); \
} while (0)
+#define INIT_DELAYED_WORK_ON_STACK(_work, _func) \
+ do { \
+ INIT_WORK(&(_work)->work, (_func)); \
+ init_timer_on_stack(&(_work)->timer); \
+ } while (0)
+
#define INIT_DELAYED_WORK_DEFERRABLE(_work, _func) \
do { \
INIT_WORK(&(_work)->work, (_func)); \
--
cgit v1.2.3-70-g09d2