From: Christian Brauner Date: Mon, 12 Jan 2026 10:07:30 +0000 (+0100) Subject: Merge patch series "Fix vm.dirtytime_expire_seconds=0 causing 100% CPU" X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e16688084df76e719b329a1a56b338ec491002e0;p=thirdparty%2Flinux.git Merge patch series "Fix vm.dirtytime_expire_seconds=0 causing 100% CPU" Laveesh Bansal 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 --- e16688084df76e719b329a1a56b338ec491002e0