From: Mel Gorman <mgorman@techsingularity.net>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Vlastimil Babka <vbabka@suse.cz>, Hillf Danton <hdanton@sina.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Michal Hocko <mhocko@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: [PATCH] mm/page_alloc: Introduce vm.percpu_pagelist_high_fraction -fix
Date: Fri, 28 May 2021 16:10:10 +0100 [thread overview]
Message-ID: <20210528151010.GQ30378@techsingularity.net> (raw)
Vlastimil Babka pointed out that the documentation for
vm.percpu_pagelist_high_fraction is potentially misleading so fix it.
This is a fix to the mmotm patch
mm-page_alloc-introduce-vmpercpu_pagelist_high_fraction.patch
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
---
Documentation/admin-guide/sysctl/vm.rst | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index e85c2f21d209..2da25735a629 100644
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -793,15 +793,16 @@ why oom happens. You can get snapshot.
percpu_pagelist_high_fraction
=============================
-This is the fraction of pages in each zone that are allocated for each
-per cpu page list. The min value for this is 8. It means that we do
-not allow more than 1/8th of pages in each zone to be allocated in any
-single per_cpu_pagelist. This entry only changes the value of hot per
-cpu pagelists. User can specify a number like 100 to allocate 1/100th
-of each zone to each per cpu page list.
-
-The batch value of each per cpu pagelist remains the same regardless of the
-value of the high fraction so allocation latencies are unaffected.
+This is the fraction of pages in each zone that are can be stored to
+per-cpu page lists. It is an upper boundary that is divided depending
+on the number of online CPUs. The min value for this is 8 which means
+that we do not allow more than 1/8th of pages in each zone to be stored
+on per-cpu page lists. This entry only changes the value of hot per-cpu
+page lists. A user can specify a number like 100 to allocate 1/100th of
+each zone between per-cpu lists.
+
+The batch value of each per-cpu page list remains the same regardless of
+the value of the high fraction so allocation latencies are unaffected.
The initial value is zero. Kernel uses this value to set the high pcp->high
mark based on the low watermark for the zone and the number of local
reply other threads:[~2021-05-28 15:10 UTC|newest]
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