linux-kernel - Re: [RFC PATCH] mm: check global free_list if there is ongoing reclaiming when pcp fail

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Date:   Mon, 19 Sep 2022 11:16:29 +0100
From:   Mel Gorman <mgorman@...hsingularity.net>
To:     "zhaoyang.huang" <zhaoyang.huang@...soc.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Zhaoyang Huang <huangzhaoyang@...il.com>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, ke.wang@...soc.com
Subject: Re: [RFC PATCH] mm: check global free_list if there is ongoing
 reclaiming when pcp fail

On Fri, Sep 16, 2022 at 06:58:12PM +0800, zhaoyang.huang wrote:
> From: Zhaoyang Huang <zhaoyang.huang@...soc.com>
> 
> Check the global free list again even if rmqueue_bulk failed for pcp pages when
> there is ongoing reclaiming, which could eliminate potential direct reclaim by
> chance.
> 
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@...soc.com>

Patch does not apply and may be based on a custom kernel that introduced
a problem. There is no description of what problem this is trying to
fix. Checking the status of reclaim for a specific zone in this path would
be a little unexpected.  If allocation pressure is exceeding the ability
of reclaim to make progress then the caller likely needs to take action
like direct reclaim. If the allocation failure is due to a high-order
failure then it may need to enter direct compaction etc.

-- 
Mel Gorman
SUSE Labs