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[PATCH] schedule_on_each_cpu(): reduce kmalloc() size

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schedule_on_each_cpu() presently does a large kmalloc - 96 kbytes on 1024 CPU
64-bit.

Rework it so that we do one 8192-byte allocation and then a pile of tiny ones,
via alloc_percpu().  This has a much higher chance of success (100% in the
current VM).

This also has the effect of reducing the memory requirements from NR_CPUS*n to
num_possible_cpus()*n.

Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andrew Morton 2006-06-25 05:47:49 -07:00 committed by Linus Torvalds
parent 232acbcf53
commit b61367732f
1 changed files with 20 additions and 8 deletions
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28
kernel/workqueue.c
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@ -428,22 +428,34 @@ int schedule_delayed_work_on(int cpu,
return ret;
}
int schedule_on_each_cpu(void (*func) (void *info), void *info)
/**
* schedule_on_each_cpu - call a function on each online CPU from keventd
* @func: the function to call
* @info: a pointer to pass to func()
*
* Returns zero on success.
* Returns -ve errno on failure.
*
* Appears to be racy against CPU hotplug.
*
* schedule_on_each_cpu() is very slow.
*/
int schedule_on_each_cpu(void (*func)(void *info), void *info)
{
int cpu;
struct work_struct *work;
struct work_struct *works;
work = kmalloc(NR_CPUS * sizeof(struct work_struct), GFP_KERNEL);
if (!work)
works = alloc_percpu(struct work_struct);
if (!works)
return -ENOMEM;
for_each_online_cpu(cpu) {
INIT_WORK(work + cpu, func, info);
INIT_WORK(per_cpu_ptr(works, cpu), func, info);
__queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu),
work + cpu);
per_cpu_ptr(works, cpu));
}
flush_workqueue(keventd_wq);
kfree(work);
free_percpu(works);
return 0;
}