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AJvYcCUQ3m8eruHc5I1divw199g0PBeWWGao3vLdi8jWuW1PgpFGPSLrHVS9hnIRg58tmgdvTg37+baxtA==@kvack.org X-Gm-Message-State: AOJu0YwVR+DxdD8RRAVYwGHUxo7b0VdL5vvi/cXJp/E4HfR9N8Fj9tgM ixiD0vDwQFsvCYf0VkP5IChX12XDlwdPUIJ0j8Y6nCHiJohf6bhTQcCPfTOC3HGMPp/3h2rPFc+ R6R5BW279GFiAHUdY8Hf2HM8uwuk= X-Gm-Gg: ASbGnctenpxhLQhDvLAdus9rCR9FIMT0ujhFN8iv8xtB8mPYESxNkwZYZK8a9L2kcFN Alu1aIgxuCIEKHIvbc2KNbSNB2bp6YTAm4uHc0HTRfoJIgUwtaS1Fukw3Pk7XRVyXgDbdi44MPC 6DS1wvKfXLbyIszleOs828ttllNFk= X-Google-Smtp-Source: AGHT+IEkV/RgXiDW1D8bFaCv+KKAgjpHm568eaTLfIKUTtEBWXzInj8ZP8S4Inyj5ExQY+g0lXgDbTw947IrRNQtLjo= X-Received: by 2002:a05:6902:2b83:b0:e73:126c:fdfa with SMTP id 3f1490d57ef6-e7316829eaamr3328647276.29.1745591332754; Fri, 25 Apr 2025 07:28:52 -0700 (PDT) MIME-Version: 1.0 References: <20250424153815.4003-1-haowenchao22@gmail.com> <20250424194200.GD840@cmpxchg.org> In-Reply-To: <20250424194200.GD840@cmpxchg.org> From: Wenchao Hao Date: Fri, 25 Apr 2025 22:28:42 +0800 X-Gm-Features: ATxdqUGPWMKahfXsbho5V4QfMOQWdI9zAo2KvWvl_MBadhn3O8BUxSa77qltUjM Message-ID: Subject: Re: [PATCH] mm/compaction: do not break pages whose order is larger than target order To: Johannes Weiner Cc: Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: C6AFBC0008 X-Stat-Signature: ejiz7d1hbybrmdpdw359sri6q4zjb3tq X-HE-Tag: 1745591333-143598 X-HE-Meta: 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 S/nepdde tgn7cd0Ry3t+MB8NQpT+uXq/pnXSPVQ3cpU4JK+gxqHbHU8PJzzUqylqDbCZ12P3Lqpt64WPACSMndZiha1zohXMfebyqqNMaH7jkAgAzw2NN1wKYC0XvWza3ZJwXXbKD/gOhrjb2F9FdE6LnAhifTt8M3Fl/p8YOxpHAAECJMYzS/cZuffAn5QwiY7vXbK9J3D2YUwBvvdV/wnsTkA/KHgGcKmsG66Aeu8TJKkMlzyty2YDuGQJ+mFjGD1DIdiavBiCJWWj13fz+dSsJDOirADZA3/6xNXQpOQ826rk4nTSM6h7h6ULGs4dj+zGF4pD8wthy++ZydR2vB9smZCLP4me/daNoi/vLzJ7B2rpq3n8huhmU9Qerux3I8QMTyKYno0WyvxEXdNGmsTHS3xGi94hJlcm3RB3hiqjmOfbKKkFs266gGx5LpPnE6w== 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, Apr 25, 2025 at 3:42=E2=80=AFAM Johannes Weiner wrote: > > On Thu, Apr 24, 2025 at 11:38:15PM +0800, Wenchao Hao wrote: > > When scanning free pages for memory compaction, if the compaction targe= t > > order is explicitly specified, do not split pages in buddy whose order > > are larger than compaction target order. > > Have you observed this to be an issue in practice? > > compact_finished() would have bailed if such a page had existed. > Yes, when proactive memory compaction is enabled, there may be situations where the order of isolated free pages is greater than the compaction requested order, and compact_finished() will return continue. > compaction_capture() would steal such a page upon production. > > It could help with blocks freed by chance from somewhere else, where > you'd preserve it to grab it later from the allocation retry. But if > that's the target, it might be better to indeed isolate the page, and > then capture it inside compaction_alloc()?