lkml.org 
[lkml]   [2012]   [Oct]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch for-3.7] mm, mempolicy: fix printing stack contents in numa_maps
On Wed, 17 Oct 2012, KOSAKI Motohiro wrote:

> > I think this refcounting is better than using task_lock().
>
> I don't think so. get_vma_policy() is used from fast path. In other
> words, number of
> atomic ops is sensible for allocation performance.

There are enhancements that we can make with refcounting: for instance, we
may want to avoid doing it in the super-fast path when the policy is
default_policy and then just do

if (mpol != &default_policy)
mpol_put(mpol);

> Instead, I'd like
> to use spinlock
> for shared mempolicy instead of mutex.
>

Um, this was just changed to a mutex last week in commit b22d127a39dd
("mempolicy: fix a race in shared_policy_replace()") so that sp_alloc()
can be done with GFP_KERNEL, so I didn't consider reverting that behavior.
Are you nacking that patch, which you acked, now?


\
 
 \ /
  Last update: 2012-10-17 22:41    [W:1.344 / U:0.508 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site