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| author | Peter Zijlstra <peterz@infradead.org> | 2008-11-24 17:06:57 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-01-07 18:52:44 +0100 |
| commit | 490dea45d00f01847ebebd007685d564aaf2cd98 (patch) | |
| tree | a1f559fd497b10c21479b378ffb262d517cb627b /include/linux/sched.h | |
| parent | ede6f5aea054d3fb67c78857f7abdee602302043 (diff) | |
| download | lwn-490dea45d00f01847ebebd007685d564aaf2cd98.tar.gz lwn-490dea45d00f01847ebebd007685d564aaf2cd98.zip | |
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>
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 4cae9b81a1f8..c20943eabb4c 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); } /* |