GitHub-Mirror/linux-bl808
2
0
Fork 0
mirror of https://github.com/Fishwaldo/linux-bl808.git synced 2025-06-17 20:25:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

itimers: remove the per-cpu-ish-ness

Browse source 
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>
This commit is contained in:
Peter Zijlstra 2008-11-24 17:06:57 +01:00 • committed by Ingo Molnar
parent ede6f5aea0
commit 490dea45d0
5 changed files with 46 additions and 107 deletions
Download patch file Download diff file Expand all files Collapse all files

29
include/linux/sched.h
View file

@ -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(struct task_struct *tsk, struct task_cputime *times)
{
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 void thread_group_cputime_init(struct signal_struct *sig)
{
sig->cputime.totals = NULL;
}
sig->cputime.totals = (struct task_cputime){
.utime = cputime_zero,
.stime = cputime_zero,
.sum_exec_runtime = 0,
};
static inline int thread_group_cputime_clone_thread(struct task_struct *curr)
{
if (curr->signal->cputime.totals)
return 0;
return thread_group_cputime_alloc(curr);
spin_lock_init(&sig->cputime.totals.lock);
}
static inline void thread_group_cputime_free(struct signal_struct *sig)
{
free_percpu(sig->cputime.totals);
}
/*