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Message-ID: <0a6603c4-ac05-460c-8bad-66813570b426@gmail.com>
Date: Wed, 5 Jun 2024 11:44:24 +0800
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Subject: Re: [PATCH 09/10] mm/ksm: calc_checksum for folio
To: David Hildenbrand <david@redhat.com>, alexs@kernel.org,
 Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
 linux-kernel@vger.kernel.org, izik.eidus@ravellosystems.com,
 willy@infradead.org, aarcange@redhat.com, chrisw@sous-sol.org,
 hughd@google.com
References: <20240604042454.2012091-1-alexs@kernel.org>
 <20240604042454.2012091-10-alexs@kernel.org>
 <ddb33c85-35e4-47c5-8a81-13a2012aac5e@redhat.com>
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From: Alex Shi <seakeel@gmail.com>
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On 6/4/24 9:18 PM, David Hildenbrand wrote:
>> @@ -2369,7 +2371,7 @@ static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_ite
>>        * don't want to insert it in the unstable tree, and we don't want
>>        * to waste our time searching for something identical to it there.
>>        */
>> -    checksum = calc_checksum(page);
>> +    checksum = calc_checksum(folio);
> 
> So for a large folio you suddenly checksum more than a single page? That's wrong.
> 
> Or am I missing something?

I am not sure if this change are good too, anyway, comparing the whole folio may have it advantages on efficiency, but more splitting do save more pages.

Anyway, this change could be dropped.

Thanks!