Message-ID: <cf3788c7-1b84-dac2-6f83-6da6baa36dd6@suse.cz>
Date:   Tue, 7 Feb 2023 18:10:13 +0100
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Subject: Re: [PATCH 3/4] mm, compaction: Finish scanning the current pageblock
 if requested
Content-Language: en-US
To:     Mel Gorman <mgorman@techsingularity.net>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Jiri Slaby <jirislaby@kernel.org>,
        Maxim Levitsky <mlevitsk@redhat.com>,
        Michal Hocko <mhocko@kernel.org>,
        Pedro Falcato <pedro.falcato@gmail.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Chuyi Zhou <zhouchuyi@bytedance.com>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
References: <20230125134434.18017-1-mgorman@techsingularity.net>
 <20230125134434.18017-4-mgorman@techsingularity.net>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20230125134434.18017-4-mgorman@techsingularity.net>
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Precedence: bulk

On 1/25/23 14:44, Mel Gorman wrote:
> cc->finish_pageblock is set when the current pageblock should be
> rescanned but fast_find_migrateblock can select an alternative
> block. Disable fast_find_migrateblock when the current pageblock
> scan should be completed.
> 
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>

Acked-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>  mm/compaction.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 28711a21a8a2..4b3a0238879c 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -1762,6 +1762,13 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc)
>  	if (cc->ignore_skip_hint)
>  		return pfn;
>  
> +	/*
> +	 * If the pageblock should be finished then do not select a different
> +	 * pageblock.
> +	 */
> +	if (cc->finish_pageblock)
> +		return pfn;
> +
>  	/*
>  	 * If the migrate_pfn is not at the start of a zone or the start
>  	 * of a pageblock then assume this is a continuation of a previous