[PATCH] Documentation: incorrect formula to calculate CommitLimit value

From: Petr Oros
Date: Thu May 22 2014 - 08:05:17 EST


The formula to calculate "CommitLimit" value mentioned in kernel documentation is incorrect.
Right formula is: CommitLimit = ([total RAM pages] - [total huge TLB pages]) * overcommit_ratio / 100 + [total swap pages]

Signed-off-by: Petr Oros <poros@xxxxxxxxxx>
---
Documentation/filesystems/proc.txt | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 8b9cd8e..b58d764 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -854,7 +854,8 @@ WritebackTmp: Memory used by FUSE for temporary writeback buffers
if strict overcommit accounting is enabled (mode 2 in
'vm.overcommit_memory').
The CommitLimit is calculated with the following formula:
- CommitLimit = ('vm.overcommit_ratio' * Physical RAM) + Swap
+ CommitLimit = ([total RAM pages] - [total huge TLB pages]) *
+ overcommit_ratio / 100 + [total swap pages]
For example, on a system with 1G of physical RAM and 7G
of swap with a `vm.overcommit_ratio` of 30 it would
yield a CommitLimit of 7.3G.
--
1.9.0


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