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From: Michal Hocko <mhocko@suse.com>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Roman Gushchin <guro@fb.com>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH] mm: memcontrol: restore proper dirty throttling when memory.high changes
Date: Fri, 31 Jul 2020 10:18:04 +0200	[thread overview]
Message-ID: <20200731081804.GK18727@dhcp22.suse.cz> (raw)
In-Reply-To: <20200728135210.379885-1-hannes@cmpxchg.org>

On Tue 28-07-20 09:52:09, Johannes Weiner wrote:
> Commit 8c8c383c04f6 ("mm: memcontrol: try harder to set a new
> memory.high") inadvertently removed a callback to recalculate the
> writeback cache size in light of a newly configured memory.high limit.
> 
> Without letting the writeback cache know about a potentially heavily
> reduced limit, it may permit too many dirty pages, which can cause
> unnecessary reclaim latencies or even avoidable OOM situations.
> 
> This was spotted while reading the code, it hasn't knowingly caused
> any problems in practice so far.
> 
> Fixes: 8c8c383c04f6 ("mm: memcontrol: try harder to set a new memory.high")
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  mm/memcontrol.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 13f559af1ab6..805a44bf948c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -6071,6 +6071,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
>  			break;
>  	}
>  
> +	memcg_wb_domain_size_changed(memcg);
>  	return nbytes;
>  }
>  
> -- 
> 2.27.0

-- 
Michal Hocko
SUSE Labs

WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>
To: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>
Cc: Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Roman Gushchin <guro-b10kYP2dOMg@public.gmane.org>,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	kernel-team-b10kYP2dOMg@public.gmane.org
Subject: Re: [PATCH] mm: memcontrol: restore proper dirty throttling when memory.high changes
Date: Fri, 31 Jul 2020 10:18:04 +0200	[thread overview]
Message-ID: <20200731081804.GK18727@dhcp22.suse.cz> (raw)
In-Reply-To: <20200728135210.379885-1-hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>

On Tue 28-07-20 09:52:09, Johannes Weiner wrote:
> Commit 8c8c383c04f6 ("mm: memcontrol: try harder to set a new
> memory.high") inadvertently removed a callback to recalculate the
> writeback cache size in light of a newly configured memory.high limit.
> 
> Without letting the writeback cache know about a potentially heavily
> reduced limit, it may permit too many dirty pages, which can cause
> unnecessary reclaim latencies or even avoidable OOM situations.
> 
> This was spotted while reading the code, it hasn't knowingly caused
> any problems in practice so far.
> 
> Fixes: 8c8c383c04f6 ("mm: memcontrol: try harder to set a new memory.high")
> Signed-off-by: Johannes Weiner <hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org>

Acked-by: Michal Hocko <mhocko-IBi9RG/b67k@public.gmane.org>

> ---
>  mm/memcontrol.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 13f559af1ab6..805a44bf948c 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -6071,6 +6071,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
>  			break;
>  	}
>  
> +	memcg_wb_domain_size_changed(memcg);
>  	return nbytes;
>  }
>  
> -- 
> 2.27.0

-- 
Michal Hocko
SUSE Labs

  parent reply	other threads:[~2020-07-31  8:18 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-28 13:52 [PATCH] mm: memcontrol: restore proper dirty throttling when memory.high changes Johannes Weiner
2020-07-28 13:52 ` Johannes Weiner
2020-07-28 14:07 ` Chris Down
2020-07-28 14:07   ` Chris Down
2020-07-28 15:07 ` Shakeel Butt
2020-07-28 15:07   ` Shakeel Butt
2020-07-31  8:18 ` Michal Hocko [this message]
2020-07-31  8:18   ` Michal Hocko

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