lkml.org 
[lkml]   [2014]   [Jul]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch 2/3] mm, oom: remove unnecessary check for NULL zonelist
On Wed, Jul 23, 2014 at 06:16:32PM -0700, David Rientjes wrote:
> If the pagefault handler is modified to pass a non-NULL zonelist then an
> unnecessary check for a NULL zonelist in constrained_alloc() can be removed.
>
> Signed-off-by: David Rientjes <rientjes@google.com>
> ---
> mm/oom_kill.c | 4 +---
> 1 file changed, 1 insertion(+), 3 deletions(-)
>
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -208,8 +208,6 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
> /* Default to all available memory */
> *totalpages = totalram_pages + total_swap_pages;
>
> - if (!zonelist)
> - return CONSTRAINT_NONE;
> /*
> * Reach here only when __GFP_NOFAIL is used. So, we should avoid
> * to kill current.We have to random task kill in this case.
> @@ -696,7 +694,7 @@ void pagefault_out_of_memory(void)
>
> zonelist = node_zonelist(first_memory_node, GFP_KERNEL);
> if (try_set_zonelist_oom(zonelist, GFP_KERNEL)) {
> - out_of_memory(NULL, 0, 0, NULL, false);
> + out_of_memory(zonelist, 0, 0, NULL, false);

out_of_memory() wants the zonelist that was used during allocation,
not just the random first node's zonelist that's simply picked to
serialize page fault OOM kills system-wide.

This would even change how panic_on_oom behaves for page fault OOMs
(in a completely unpredictable way) if we get CONSTRAINED_CPUSET.

This change makes no sense to me.


\
 
 \ /
  Last update: 2014-07-31 18:01    [W:0.056 / U:0.716 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site