Re: [BUGFIX][PATCH] oom-kill: fix NUMA consraint check with nodemask v4.2

[David Rientjes <rientjes@google.com>]

On Wed, 11 Nov 2009, KAMEZAWA Hiroyuki wrote:

> From: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>
> 
> Fixing node-oriented allocation handling in oom-kill.c
> I myself think this as bugfix not as ehnancement.
> 
> In these days, things are changed as
>   - alloc_pages() eats nodemask as its arguments, __alloc_pages_nodemask().
>   - mempolicy don't maintain its own private zonelists.
>   (And cpuset doesn't use nodemask for __alloc_pages_nodemask())
> 
> So, current oom-killer's check function is wrong.
> 
> This patch does
>   - check nodemask, if nodemask && nodemask doesn't cover all
>     node_states[N_HIGH_MEMORY], this is CONSTRAINT_MEMORY_POLICY.
>   - Scan all zonelist under nodemask, if it hits cpuset's wall
>     this faiulre is from cpuset.
> And
>   - modifies the caller of out_of_memory not to call oom if __GFP_THISNODE.
>     This doesn't change "current" behavior. If callers use __GFP_THISNODE
>     it should handle "page allocation failure" by itself.
> 
>   - handle __GFP_NOFAIL+__GFP_THISNODE path.
>     This is something like a FIXME but this gfpmask is not used now.
> 
> Changelog: 2009/11/11(2)
>  - uses nodes_subset().
>  - clean up.
>  - added __GFP_NOFAIL case. And added waring.
>  - removed inline
>  - removed 'ret'
> 
> Changelog: 2009/11/11
>  - fixed nodes_equal() calculation.
>  - return CONSTRAINT_MEMPOLICY always if given nodemask is not enough big.
> 
> Changelog: 2009/11/06
>  - fixed lack of oom.h
> 
> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>

Acked-by: David Rientjes <rientjes@google.com>

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