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b=h67Rk/Mgh6v0/yt1TXHrNCtuEEH5o2qoHegLeGlNDBLYcwN1yd4ORLxymfm+mARqx 8ykDCr4OlpJd6nqWIU24jSRypkf/8DAhuE7cpAt4IhaJoNw7Rk6IAqSCqto0o/YPzK ilQIHsXaDAAz3AGYtNgiTqdDBmed4sX7dBr3aqjNz/Z9l0ALUsHPym8r5omHRC9+r9 Jxy/Uh/wIAjo+kkEZISKORtKQgrPzB5FhVMewrJrsp7a+OZ6daTIn7q4auBq6o4g+B M1iHWqw35cmU/0UvjjsKswrlVPwmWKw5L6bngXUhUHCfevojFI7sdAyLP+qPeEf1+z zKjfMtIp4T0LA== From: SJ Park To: Cc: SJ Park , Andrew Morton , damon@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: [RFC PATCH 00/11] mm/damon: refactor damon_{start,stop,commit}() for simple error handling Date: Sat, 4 Jul 2026 11:11:23 -0700 Message-ID: <20260704181135.132956-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 9C2D040003 X-Stat-Signature: im81ei98xfdg35afbauhabrnramuph36 X-HE-Tag: 1783188705-485024 X-HE-Meta: U2FsdGVkX1+l86ao91yCrM4gQG/QwWTaok51XuQOVYT4yvJmcD4PTJQE6F/6t2hH+SYxDGhAQo85YnNOlIMiztSWP6XP/wa3unFINYJ2tRDi3z6JUPLP2HL0WlurLYJW7FMi8cuaJPgIgvHVMPp6o3DFdcO278vnwSYFUi9qsldP6Ayx15ef0HXQwphs0cfEUXHPOoiTBRnXmkDcRG7DflvXbyIfIRy9atBhTQKPEyHY3rNBQ8w7MnPdktdjlseyvui/P45yrpLMuPe3L29X9Gr+E7DSoRslxGztgj2LYkomT4Jg3ZvcHQv8AWoBEX8v6TVEyzVLnP7dIN//v6mjBETyM9yAtczwN1iPZtiXax7bNvl+u7oscZj3gulFXohyavjDEAzIY71X2C2YYxr+ewgf6Ej3In7kXkVC5Br6aqkPNCtcpn2esk+DXPVIDDZHWoIENz1hbLbRx2aQ+pXeqU0g33//EACeJ1g0uCxLUQLelO2EQqWEvmhCvrkyQlSO8IDnYlMM1RhZy4Ku7ibxRaXGQcwALLXrQ5vFHQ0+8JikW2QcznUrNW5ENMtGSi91Ai6JgK5EWirp1KYh2W6apCECz58UpPfQiw/UKe0+Onxd+gfOBREPNRo9DA1knu7zVV5VAJNjg2e89c+a4qiAwr9cT9K0K2D4AHfQvnosu6crQm2fwiCvVRgkija7XDXC7SEsK0OHcXSzZ96cgysiFW/aTCf/houZgKws83izFUyYoFtHlMtBWnuOXBcinFus+WBXgq9d/V6IQjg0oprAJ0HTxd561ImnCrIRvpCbmVtGQkmYgEBlGwhTRmPBMXftH5OkRsqxKdn5D4mEePEKUJK9SARUdm5KYsmvukSbCWwMf6CWqwqOucG1+PLBbgTFFxlwMoxvGRty9xVtFoYVvaiGA0cUzdd6EA2/ArWJ8yTTkEmIrvEccgY+SpOmktFfGTjaoYuM5Rvl8xk7RwC szw6LMxk IIcJramrm6jaZB8jit6hv4hliOmzNSvkMuKv2rw6MUn/Oo34+yRv2Onw+RXWDHxcCr4TZsXR4TjYEvAivqPJM+0VUS5krHwZ+gFaz9f2jNxc2pCK7hm7qULV77orCKZBxb4jtXHxXFnhE89e/OFQIwPU0dKTXNQmhjDQvwNNeFGpGBXMpoTpqAbnL89xeHoOVk0IC4x2FtYCiSztMBi+L86T7L0xkWaOBL9NBuR5lOTvgNMmitaPrXFxBFyGxt9eMuv12 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: damon_start() and damon_stop() could leave a few of requested DAMON contexts running when they return an error. damon_commit() failure stops the DAMON context, but in an asynchronous way. Callers should stop the left-over DAMON contexts. It is easy to mistake, and indeed a few bugs from such mistakes were found and fixed. Refactor the core API functions to stop all contexts to avoid the mistakes. Also remove the unnecessary error handlings from callers. Patches Sequence ================ Patch 1 refactors damon_start() to ensure all contexts are stopped for failures. Patch 2 updates unnecessary damon_start() error handling from mtier sample module. Patch 3 refactors damon_stop() to always success. Patches 4-6 updates callers (damon_{sysfs,reclaim lru_sort}) to ignore the return value. Patch 7 update damon_stop() return value to void. Patch 8 simplifies damon_stop() error handling in mtier sample module. Patch 9 refactors damon_call() to stop the context before returning the error. Patches 10 and 11 remove unnecessary error handlings from callers (wsse and prcl sample modules). SJ Park (11): mm/damon/core: stop ctxs in damon_start() before returning an error samples/damon/mtier: do not stop first context for damon_start() failure mm/damon/core: make damon_stop() never fails mm/damon/sysfs: ignore damon_stop() return value mm/damon/reclaaim: ignore damon_stop() return value mm/damon/lru_sort: ignore damon_stop() return value mm/damon/core: change damon_stop() return type to void samples/damon/mtier: stop all contexts with single damon_stop() call mm/damon/core: stop ctx in damon_call() before reruning an error samples/damon/wsse: do not stop ctx for damon_call() failure samples/damon/prcl: do not stop DAMON for damon_call() failure include/linux/damon.h | 2 +- mm/damon/core.c | 37 ++++++++++++++++++------------------- mm/damon/lru_sort.c | 6 ++++-- mm/damon/reclaim.c | 6 ++++-- mm/damon/sysfs.c | 3 ++- samples/damon/mtier.c | 5 +---- samples/damon/prcl.c | 4 +--- samples/damon/wsse.c | 4 +--- 8 files changed, 32 insertions(+), 35 deletions(-) base-commit: 39f9f608b1858e65db6d2766d692a7a700b1e0fb -- 2.47.3