Re: [patch] make sysctl_overcommit_memory enumeration sensible

[Nick Piggin]

Coywolf Qi Hunt wrote:
> I see system admins often confused when they sysctl vm.overcommit_memory.
> This patch makes overcommit_memory enumeration sensible.

What's the point? The current has been there for a long time, and
is well documented.

> 0 - no overcommit
> 1 - always overcommit
> 2 - heuristic overcommit (default)
>
> I don't feel this would break any userspace scripts.

You mean, except for the ones that go `echo 0 > /proc/sys/vm/overcommit_memory`;
or `echo 2 > /proc/sys/vm/overcommit_memory` ?

And those sysctl configuration files that get set at bootup?

> If it seems OK, I'll
> update the documents.
>
> Signed-off-by: Coywolf Qi Hunt <qiyong@xxxxxxxxx>
> ---
> diff --git a/include/linux/mman.h b/include/linux/mman.h
> index 18a5689..e50f5ad 100644
> --- a/include/linux/mman.h
> +++ b/include/linux/mman.h
> @@ -10,9 +10,9 @@
>  #define MREMAP_MAYMOVE	1
>  #define MREMAP_FIXED	2
>  
> -#define OVERCOMMIT_GUESS		0
> +#define OVERCOMMIT_NEVER		0
>  #define OVERCOMMIT_ALWAYS		1
> -#define OVERCOMMIT_NEVER		2
> +#define OVERCOMMIT_GUESS		2
>  extern int sysctl_overcommit_memory;
>  extern int sysctl_overcommit_ratio;
>  extern atomic_t vm_committed_space;


--
SUSE Labs, Novell Inc.
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