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AJvYcCVLMbfQWwRfrBtyKzc2qCz9Nk/fXMAgMZMGXytgEBtyVFz0fA4mAyoi+fkIMZLnkpBXRLfbJaGdbg==@kvack.org X-Gm-Message-State: AOJu0YwfcZJtggGr8aYBwaMMpfTYKsAZBsRrjze8qL0h5/xIU7Q/W0Tg c5MFxmrDRR2/ZpXDXLBtEMjbFQhynKlfF+LbTRClH3Q0VtTwDqWnYshNKYEDyeKV47cCdMDDpfA BAxVEyNcfzx5Y8Sm5uqepRi3rB0LxnWbSrMuH X-Gm-Gg: ASbGnctotazVdgaUUHZW425tu4ro2IpnFspRuRvjlN1pxGPXKXuAZXm8gH/fdEpMKn4 joRySSyT7UHLjq9APIjEEQDUdbxsuAIcwsibQDQ7kkiOqPofFUaq4lLxqumnuPadPfa7O/dSJvo LTbeb/HKcAcrtoVb6zVirDdYQ9PQ== X-Google-Smtp-Source: AGHT+IFSgyka4WC1voAzOEbVYGRfiKD2rPwZmgBJm5bmCEG2w77v71gm7DM31qNjr/YtvVbNnr/XQWUzc/NWKh6R9Qk= X-Received: by 2002:a05:622a:4acf:b0:476:d668:fd1c with SMTP id d75a77b69052e-4771e0a7e7dmr5053721cf.2.1742573600117; Fri, 21 Mar 2025 09:13:20 -0700 (PDT) MIME-Version: 1.0 References: <20250320173931.1583800-1-surenb@google.com> <20250320173931.1583800-3-surenb@google.com> In-Reply-To: From: Suren Baghdasaryan Date: Fri, 21 Mar 2025 09:13:09 -0700 X-Gm-Features: AQ5f1Jr9bSIHVG9XyNi5uOulPdcHUxw5kGAy9us8_XrILBTKaK6kzxC5mMI3vcM Message-ID: Subject: Re: [RFC 2/3] mm: introduce GCMA To: Christoph Hellwig Cc: akpm@linux-foundation.org, willy@infradead.org, david@redhat.com, vbabka@suse.cz, lorenzo.stoakes@oracle.com, liam.howlett@oracle.com, alexandru.elisei@arm.com, peterx@redhat.com, hannes@cmpxchg.org, mhocko@kernel.org, m.szyprowski@samsung.com, iamjoonsoo.kim@lge.com, mina86@mina86.com, axboe@kernel.dk, viro@zeniv.linux.org.uk, brauner@kernel.org, jack@suse.cz, hbathini@linux.ibm.com, sourabhjain@linux.ibm.com, ritesh.list@gmail.com, aneesh.kumar@kernel.org, bhelgaas@google.com, sj@kernel.org, fvdl@google.com, ziy@nvidia.com, yuzhao@google.com, minchan@kernel.org, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, Minchan Kim Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 4A05140015 X-Stat-Signature: r9h7mn3i7y5bfahxp459nsrpd3h8hz37 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1742573602-300631 X-HE-Meta: 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 Kc7fBaRd O/n9vSrIqFUAXWds= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000002, 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 20, 2025 at 10:14=E2=80=AFPM Christoph Hellwig wrote: > > On Thu, Mar 20, 2025 at 10:39:30AM -0700, Suren Baghdasaryan wrote: > > From: Minchan Kim > > > > This patch introduces GCMA (Guaranteed Contiguous Memory Allocator) > > cleacache backend which reserves some amount of memory at the boot > > and then donates it to store clean file-backed pages in the cleancache. > > GCMA aims to guarantee contiguous memory allocation success as well as > > low and deterministic allocation latency. > > > > Notes: > > Originally, the idea was posted by SeongJae Park and Minchan Kim [1]. > > Later Minchan reworked it to be used in Android as a reference for > > Android vendors to use [2]. > > That is not a very good summay. It needs to explain how you ensure > that the pages do stay clean forever. Sure, I'm happy to improve the description. Do you want more details about how only clean pages end up in the cleancache and how they get invalidated once the original page gets modified? Or is the concern that donated pages might be changed by the donor without taking them away from the cleancache? >