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Thu, 21 Mar 2024 17:18:43 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Chris Li Date: Thu, 21 Mar 2024 17:18:32 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [RFC] Storing same-filled pages without a zswap_entry To: Yosry Ahmed Cc: Johannes Weiner , Nhat Pham , Chengming Zhou , Linux-MM Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4406B140002 X-Rspam-User: X-Rspamd-Server: rspam02 X-Stat-Signature: rw1ajs3rrjjizcehhh4fjf75ydkqotwh X-HE-Tag: 1711066728-26557 X-HE-Meta: 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 rDa5q0Ub bXlB/z4O/7LjfXntK0AviiPS+viZVZyx7T0znntxFiRceJ4bLMnIFZ5s6yFuu5Hc12o8zR02bZ8Wubq+SJvu2CRqra7hrx7e3z+b9I19jjAS7yoYWDmL9eQud9/Lx+3vTIqUEh4DEgJjOROQwlC0la6kxk8e1W7lczNc6e5Pn96DvMlWgvz9ydeXud451NJB85skGdYry59cjbSh22L5oNNoXIypt7aEXR7xEDAbW99YNBk/YbxqyYYSRkEw0GsUI1Qmr2fOJ6Yc2h+oHBzm8hkx9tw== 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 Thu, Mar 21, 2024 at 11:50=E2=80=AFAM Yosry Ahmed wrote: > > On Wed, Mar 20, 2024 at 09:26:43PM -0700, Chris Li wrote: > > > > > Another idea is we can make the zero fill zswap entry immutable and > > share by different pages. That way it does not depend on the xarray > > pointer tagging. It can share the same code path with existing zero > > fill page handling. Just don't free the zero fill entry. > > The only relevant item in zswap_entry for same-filled pages is objcg. > That cannot be shared by different pages anyway. So basically the Ah, good points about the objcg can't be shared. Chris