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Fri, 02 Feb 2024 14:25:25 -0800 (PST) MIME-Version: 1.0 References: <20240201-b4-zswap-invalidate-entry-v1-0-56ed496b6e55@bytedance.com> <20240201-b4-zswap-invalidate-entry-v1-1-56ed496b6e55@bytedance.com> In-Reply-To: <20240201-b4-zswap-invalidate-entry-v1-1-56ed496b6e55@bytedance.com> From: Nhat Pham Date: Fri, 2 Feb 2024 14:25:14 -0800 Message-ID: Subject: Re: [PATCH 1/6] mm/zswap: add more comments in shrink_memcg_cb() To: Chengming Zhou Cc: Johannes Weiner , Andrew Morton , Yosry Ahmed , linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 7BDCAC001A X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: gk9b4gmtf46trf5w8jg3oj6aqc6hqrca X-HE-Tag: 1706912726-363789 X-HE-Meta: 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 6TNseapN 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.001168, 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 Thu, Feb 1, 2024 at 7:50=E2=80=AFAM Chengming Zhou wrote: > > Add more comments in shrink_memcg_cb() to describe the deref dance > which is implemented to fix race problem between lru writeback and > swapoff, and the reason why we rotate the entry at the beginning. > > Also fix the stale comments in zswap_writeback_entry(), and add > more comments to state that we only deref the tree after we get > the swapcache reference. > > Suggested-by: Yosry Ahmed > Suggested-by: Johannes Weiner > Signed-off-by: Chengming Zhou > --- Reviewed-by: Nhat Pham