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From: Yosry Ahmed To: SeongJae Park Cc: Andrew Morton , Chengming Zhou , Johannes Weiner , Nhat Pham , kernel-team@meta.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 1/4] mm/zswap: remove unnecessary dlen writes for incompressible pages Message-ID: References: <20251003203851.43128-1-sj@kernel.org> <20251003203851.43128-2-sj@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20251003203851.43128-2-sj@kernel.org> X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Stat-Signature: jfshfp8swyf6gw86r3d7z87jp9xn6ntx X-Rspamd-Queue-Id: 392641C0010 X-Rspamd-Server: rspam09 X-HE-Tag: 1759880429-91154 X-HE-Meta: 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 PZ+Wl3dG d1NkSBYHfs8bIT2/VfjVt05Z8AD/KH/h51fQc7vmUoobeFCQVZDdXvAyFJjn3/SCnmvvjOsm9h+IGLBq3oDdzkY81xxEgAmmnVL6desCXz2ILM3j/Oq7+kWPTOC8mCdWQESv9yCK/BOOToJLqYakmyFLMl+G7KUQ11Qn/pVBcwOiHHEuMnrZv8n5/HZZLW+om4VvrAb5YhxdYYkghB1gjJczhuhHUpfANKBXR X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, Oct 03, 2025 at 01:38:48PM -0700, SeongJae Park wrote: > Incompressible pages handling logic in zswap_compress() is setting > 'dlen' as PAGE_SIZE twice. Once before deciding whether to save the > content as is, and once again after it is decided to save it as is. > But the value of 'dlen' is used only if it is decided to save the > content as is, so the first write is unnecessary. It is not causing > real user issues, but making code confusing to read. Remove the > unnecessary write operation. > > Signed-off-by: SeongJae Park Acked-by: Yosry Ahmed > --- > mm/zswap.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/mm/zswap.c b/mm/zswap.c > index c1af782e54ec..80619c8589a7 100644 > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -894,7 +894,6 @@ static bool zswap_compress(struct page *page, struct zswap_entry *entry, > * to the active LRU list in the case. > */ > if (comp_ret || !dlen || dlen >= PAGE_SIZE) { > - dlen = PAGE_SIZE; > if (!mem_cgroup_zswap_writeback_enabled( > folio_memcg(page_folio(page)))) { > comp_ret = comp_ret ? comp_ret : -EINVAL; > -- > 2.39.5