linux-kernel - Re: [PATCH] mm: memcontrol: don't throttle dying tasks on memory.high

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Message-ID: <ZaFxn7JC8FeR-Si0@tiehlicka>
Date: Fri, 12 Jan 2024 18:06:39 +0100
From: Michal Hocko <mhocko@...e.com>
To: Johannes Weiner <hannes@...xchg.org>
Cc: Roman Gushchin <roman.gushchin@...ux.dev>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Shakeel Butt <shakeelb@...gle.com>,
	Muchun Song <muchun.song@...ux.dev>, Tejun Heo <tj@...nel.org>,
	Dan Schatzberg <schatzberg.dan@...il.com>, cgroups@...r.kernel.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: memcontrol: don't throttle dying tasks on memory.high

On Thu 11-01-24 14:28:07, Johannes Weiner wrote:
[...]
> @@ -2867,11 +2882,17 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask,
>  		}
>  	} while ((memcg = parent_mem_cgroup(memcg)));
>  
> +	/*
> +	 * Reclaim is set up above to be called from the userland
> +	 * return path. But also attempt synchronous reclaim to avoid
> +	 * excessive overrun while the task is still inside the
> +	 * kernel. If this is successful, the return path will see it
> +	 * when it rechecks the overage and simply bail out.
> +	 */
>  	if (current->memcg_nr_pages_over_high > MEMCG_CHARGE_BATCH &&
>  	    !(current->flags & PF_MEMALLOC) &&
> -	    gfpflags_allow_blocking(gfp_mask)) {
> +	    gfpflags_allow_blocking(gfp_mask))
>  		mem_cgroup_handle_over_high(gfp_mask);

Have you lost the check for the dying task here?

Other than that looks good to me.
-- 
Michal Hocko
SUSE Labs