From: Zhenhua Huang <quic_zhenhuah@quicinc.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: <akpm@linux-foundation.org>, <linux-mm@kvack.org>,
<quic_tingweiz@quicinc.com>
Subject: Re: [PATCH v2] mm/page_owner.c: remove redudant drain_all_pages
Date: Fri, 9 Sep 2022 14:18:06 +0800 [thread overview]
Message-ID: <656ffdc5-2b7e-1ecb-f7a6-5456f113d190@quicinc.com> (raw)
In-Reply-To: <20220908145538.in2ttdaejp2zxwxk@techsingularity.net>
On 2022/9/8 22:55, Mel Gorman wrote:
> On Thu, Sep 08, 2022 at 06:33:24PM +0800, Zhenhua Huang wrote:
>> Remove an expensive and unnecessary operation as PCP pages are safely
>> skipped when reading page owner. PCP pages can be skipped because
>> PAGE_EXT_OWNER_ALLOCATED is cleared.
>>
>> With draining PCP pages, these pages are moved to buddy list so they
>> can be identified as buddy pages and skipped quickly. Although it improved
>> efficiency of PFN walker, the drain is guaranteed expensive that is
>> unlikely to be offset by a slight increase in efficiency when skipping
>> free pages.
>>
>> PAGE_EXT_OWNER_ALLOCATED is cleared in the page owner reset path below:
>> free_unref_page
>> -> free_unref_page_prepare
>> -> free_pcp_prepare
>> -> free_pages_prepare which do page owner
>> reset
>> -> free_unref_page_commit which add pages into pcp list
>>
>> Acked-by: Mel Gorman <mgorman@techsingularity.net>
>> Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
>
> Should be;
>
> Signed-off-by: Zhenhua Huang <quic_zhenhuah@quicinc.com>
> Acked-by: Mel Gorman <mgorman@techsingularity.net>
>
> Otherwise looks good!
Thanks Mel for your guide.
Will update.
>
prev parent reply other threads:[~2022-09-09 6:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-08 10:33 [PATCH v2] mm/page_owner.c: remove redudant drain_all_pages Zhenhua Huang
2022-09-08 14:55 ` Mel Gorman
2022-09-09 6:18 ` Zhenhua Huang [this message]
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