Re: [PATCH 10/13] x86: Move cond resched for copy_{from,to}_user intolow level code 64bit

From: KOSAKI Motohiro
Date: Tue Aug 20 2013 - 17:03:39 EST


>> Hmm. I can do that, but wouldn't that make CONFIG_PREEMPT_VOLUNTARY
>> mostly equivalent to CONFIG_PREEMPT_NONE?
>
> According the the Kconfig help, PREEMPT_VOLUNTARY is about the
> *explicit* preemption points. And we do have a lot of them in
> "might_sleep()".
>
> And personally, I think it makes a *lot* more sense to have a
> "might_sleep()" in the MM allocators than it does to have it in
> copy_from_user().

AFAIK, MM allocation already does that.

struct page *
__alloc_pages_nodemask(gfp_t gfp_mask, unsigned int order,
struct zonelist *zonelist, nodemask_t *nodemask)
{
(snip)
might_sleep_if(gfp_mask & __GFP_WAIT);


btw, Sorry for the very late response. I haven't noticed this thread.
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