Re: [PATCH 1/2] memcg: Use gfp_mask __GFP_NORETRY in try charge

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Mon, 12 Dec 2011 18:16:27 -0800
Ying Han <yinghan@google.com> wrote:

> In __mem_cgroup_try_charge() function, the parameter "oom" is passed from the
> caller indicating whether or not the charge should enter memcg oom kill. In
> fact, we should be able to eliminate that by using the existing gfp_mask and
> __GFP_NORETRY flag.
> 
> This patch removed the "oom" parameter, and add the __GFP_NORETRY flag into
> gfp_mask for those doesn't want to enter memcg oom. There is no functional
> change for those setting false to "oom" like mem_cgroup_move_parent(), but
> __GFP_NORETRY now is checked for those even setting true to "oom".
> 
> The __GFP_NORETRY is used in page allocator to bypass retry and oom kill. I
> believe there is a reason for callers to use that flag, and in memcg charge
> we need to respect it as well.
> 
> Signed-off-by: Ying Han <yinghan@google.com>


I don't like this. _GFP_NORETRY is included in GFP_RECLAIM_MASK and
may be affeced by future changes in vmscan.c


Bye,
-Kame

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