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Date: Mon, 10 Jun 2024 14:07:59 +0100
From: Matthew Wilcox <willy@infradead.org>
To: Usama Arif <usamaarif642@gmail.com>
Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, david@redhat.com,
	ying.huang@intel.com, hughd@google.com, yosryahmed@google.com,
	nphamcs@gmail.com, chengming.zhou@linux.dev, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH v3 1/2] mm: store zero pages to be swapped out in a bitmap
Message-ID: <Zmb6r6vrP2UTDQrK@casper.infradead.org>
References: <20240610121820.328876-1-usamaarif642@gmail.com>
 <20240610121820.328876-2-usamaarif642@gmail.com>
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On Mon, Jun 10, 2024 at 01:15:59PM +0100, Usama Arif wrote:
> +	if (is_folio_zero_filled(folio)) {
> +		swap_zeromap_folio_set(folio);
> +		folio_start_writeback(folio);
> +		folio_unlock(folio);
> +		folio_end_writeback(folio);

What's the point?  As far as I can see, the only thing this is going to
do is spend a lot of time messing with various counters only to end up
with incrementing NR_WRITTEN, which is wrong because you didn't actually
write it.