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Message-ID: <227d931f-18b8-48d5-8306-64940fcf1425@gmail.com>
Date: Tue, 11 Jun 2024 16:59:11 +0100
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Subject: Re: [PATCH] mm: Do not start/end writeback for pages stored in zswap
To: Chengming Zhou <chengming.zhou@linux.dev>, akpm@linux-foundation.org
Cc: willy@infradead.org, hannes@cmpxchg.org, yosryahmed@google.com,
 nphamcs@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org,
 kernel-team@meta.com, Shakeel Butt <shakeel.butt@linux.dev>
References: <20240610143037.812955-1-usamaarif642@gmail.com>
 <5d051998-015c-4da4-83f0-1b4fb9009c68@linux.dev>
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From: Usama Arif <usamaarif642@gmail.com>
In-Reply-To: <5d051998-015c-4da4-83f0-1b4fb9009c68@linux.dev>
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On 11/06/2024 10:53, Chengming Zhou wrote:
> On 2024/6/10 22:30, Usama Arif wrote:
>> start/end writeback combination incorrectly increments NR_WRITTEN
>> counter, eventhough the pages aren't written to disk. Pages successfully
>> stored in zswap should just unlock folio and return from writepage.
>>
>> Signed-off-by: Usama Arif <usamaarif642@gmail.com>
> Looks good to me, thanks.
>
> Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>


Fororgot to add:

Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>

>
>> ---
>>   mm/page_io.c | 2 --
>>   1 file changed, 2 deletions(-)
>>
>> diff --git a/mm/page_io.c b/mm/page_io.c
>> index a360857cf75d..501784d79977 100644
>> --- a/mm/page_io.c
>> +++ b/mm/page_io.c
>> @@ -196,9 +196,7 @@ int swap_writepage(struct page *page, struct writeback_control *wbc)
>>   		return ret;
>>   	}
>>   	if (zswap_store(folio)) {
>> -		folio_start_writeback(folio);
>>   		folio_unlock(folio);
>> -		folio_end_writeback(folio);
>>   		return 0;
>>   	}
>>   	if (!mem_cgroup_zswap_writeback_enabled(folio_memcg(folio))) {