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| author | Christian Brauner <brauner@kernel.org> | 2026-01-12 11:07:30 +0100 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2026-01-12 11:07:30 +0100 |
| commit | e16688084df76e719b329a1a56b338ec491002e0 (patch) | |
| tree | 963f1ef602c5429bd97e53a2a17fabc5c83798c7 /tools/perf/scripts/python | |
| parent | readdir: require opt-in for d_type flags (diff) | |
| parent | docs: clarify that dirtytime_expire_seconds=0 disables writeback (diff) | |
| download | linux-e16688084df76e719b329a1a56b338ec491002e0.tar.gz linux-e16688084df76e719b329a1a56b338ec491002e0.zip | |
Merge patch series "Fix vm.dirtytime_expire_seconds=0 causing 100% CPU"
Laveesh Bansal <laveeshb@laveeshbansal.com> says:
Setting vm.dirtytime_expire_seconds to 0 causes wakeup_dirtytime_writeback()
to reschedule itself with a delay of 0, creating an infinite busy loop that
spins kworker at 100% CPU.
This series:
- Patch 1: Fixes the bug by handling interval=0 as "disable writeback"
(consistent with dirty_writeback_centisecs behavior)
- Patch 2: Documents that setting the value to 0 disables writeback
Tested by booting kernels in QEMU with virtme-ng:
- Buggy kernel: kworker CPU spikes to ~73% when interval set to 0
- Fixed kernel: CPU remains normal, writeback correctly disabled
- Re-enabling (0 -> non-zero): writeback resumes correctly
* patches from https://patch.msgid.link/20260106145059.543282-1-laveeshb@laveeshbansal.com:
docs: clarify that dirtytime_expire_seconds=0 disables writeback
writeback: fix 100% CPU usage when dirtytime_expire_interval is 0
Link: https://patch.msgid.link/20260106145059.543282-1-laveeshb@laveeshbansal.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'tools/perf/scripts/python')
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