Re: [PATCH] Documentation: incorrect formula to calculate CommitLimit value

From: Randy Dunlap
Date: Thu May 22 2014 - 16:20:58 EST


On 05/22/2014 05:04 AM, Petr Oros wrote:
> 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>

Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

Jiri, please grab this patch.

Thanks.


> ---
> 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.
>


--
~Randy
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