linux-kernel - Re: [PATCH] mm, oom: do not check 0 mask in out_of

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Message-ID: <ZFkFnY052onmeFnp@dhcp22.suse.cz>
Date:   Mon, 8 May 2023 16:22:21 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     Haifeng Xu <haifeng.xu@...pee.com>
Cc:     shakeelb@...gle.com, hannes@...xchg.org, akpm@...ux-foundation.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm, oom: do not check 0 mask in out_of_memory()

On Mon 08-05-23 07:35:38, Haifeng Xu wrote:
> Since commit 60e2793d440a ("mm, oom: do not trigger out_of_memory
> from the #PF"), no user sets gfp_mask to 0. Remove the 0 mask check
> and update the comments.
> 
> Signed-off-by: Haifeng Xu <haifeng.xu@...pee.com>

Acked-by: Michal Hocko <mhocko@...e.com>
Thanks!

> ---
>  mm/oom_kill.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/mm/oom_kill.c b/mm/oom_kill.c
> index 044e1eed720e..612b5597d3af 100644
> --- a/mm/oom_kill.c
> +++ b/mm/oom_kill.c
> @@ -1130,12 +1130,10 @@ bool out_of_memory(struct oom_control *oc)
>  
>  	/*
>  	 * The OOM killer does not compensate for IO-less reclaim.
> -	 * pagefault_out_of_memory lost its gfp context so we have to
> -	 * make sure exclude 0 mask - all other users should have at least
> -	 * ___GFP_DIRECT_RECLAIM to get here. But mem_cgroup_oom() has to
> -	 * invoke the OOM killer even if it is a GFP_NOFS allocation.
> +	 * But mem_cgroup_oom() has to invoke the OOM killer even
> +	 * if it is a GFP_NOFS allocation.
>  	 */
> -	if (oc->gfp_mask && !(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc))
> +	if (!(oc->gfp_mask & __GFP_FS) && !is_memcg_oom(oc))
>  		return true;
>  
>  	/*
> -- 
> 2.25.1

-- 
Michal Hocko
SUSE Labs