From 61b5d77169e1d4a7b324adb1deea9c76c9170c62 Mon Sep 17 00:00:00 2001 From: Joel Savitz Date: Thu, 28 Apr 2022 23:16:01 -0700 Subject: [PATCH] Documentation/sysctl: document page_lock_unfairness commit 8d98e42fb20c25e8efdab4cc1ac46d52ba964aca upstream. commit 5ef64cc8987a ("mm: allow a controlled amount of unfairness in the page lock") introduced a new systctl but no accompanying documentation. Add a simple entry to the documentation. Link: https://lkml.kernel.org/r/20220325164437.120246-1-jsavitz@redhat.com Signed-off-by: Joel Savitz Cc: Jonathan Corbet Cc: Vlastimil Babka Cc: Mel Gorman Cc: Dave Hansen Cc: Suren Baghdasaryan Cc: Mike Rapoport Cc: "zhangyi (F)" Cc: Charan Teja Reddy Cc: Linus Torvalds Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- Documentation/admin-guide/sysctl/vm.rst | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index 64aeee1009ca..fdc9c99437d1 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -61,6 +61,7 @@ Currently, these files are in /proc/sys/vm: - overcommit_memory - overcommit_ratio - page-cluster +- page_lock_unfairness - panic_on_oom - percpu_pagelist_fraction - stat_interval @@ -741,6 +742,14 @@ extra faults and I/O delays for following faults if they would have been part of that consecutive pages readahead would have brought in. +page_lock_unfairness +==================== + +This value determines the number of times that the page lock can be +stolen from under a waiter. After the lock is stolen the number of times +specified in this file (default is 5), the "fair lock handoff" semantics +will apply, and the waiter will only be awakened if the lock can be taken. + panic_on_oom ============