linux-kernel - Re: [PATCH v4 001/002] mm: limit growth of 3% hardcoded other user reserve

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Date:	Wed, 06 Mar 2013 07:46:29 +0800
From:	Simon Jeons <simon.jeons@...il.com>
To:	Andrew Shewmaker <agshew@...il.com>
CC:	akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, alan@...rguk.ukuu.org.uk,
	ric.masonn@...il.com
Subject: Re: [PATCH v4 001/002] mm: limit growth of 3% hardcoded other user
 reserve

On 03/06/2013 07:38 AM, Andrew Shewmaker wrote:
> Limit the growth of the memory reserved for other processes
> to the smaller of 3% or 8MB.
>
> This affects only OVERCOMMIT_NEVER.
>
> Signed-off-by: Andrew Shewmaker <agshew@...il.com>

Please add changelog, otherwise it's for other guys to review.

>
> ---
>
> Rebased onto v3.8-mmotm-2013-03-01-15-50
>
> No longer assumes 4kb pages.
> Code duplicated for nommu.
>
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 49dc7d5..4eb2b1a 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -184,9 +184,11 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
>   	allowed += total_swap_pages;
>   
>   	/* Don't let a single process grow too big:
> -	   leave 3% of the size of this process for other processes */
> +	 * leave the smaller of 3% of the size of this process
> +         * or 8MB for other processes
> +         */
>   	if (mm)
> -		allowed -= mm->total_vm / 32;
> +		allowed -= min(mm->total_vm / 32, 1 << (23 - PAGE_SHIFT));
>   
>   	if (percpu_counter_read_positive(&vm_committed_as) < allowed)
>   		return 0;
> diff --git a/mm/nommu.c b/mm/nommu.c
> index f5d57a3..a93d214 100644
> --- a/mm/nommu.c
> +++ b/mm/nommu.c
> @@ -1945,9 +1945,11 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
>   	allowed += total_swap_pages;
>   
>   	/* Don't let a single process grow too big:
> -	   leave 3% of the size of this process for other processes */
> +	 * leave the smaller of 3% of the size of this process
> +         * or 8MB for other processes
> +         */
>   	if (mm)
> -		allowed -= mm->total_vm / 32;
> +		allowed -= min(mm->total_vm / 32, 1 << (23 - PAGE_SHIFT));
>   
>   	if (percpu_counter_read_positive(&vm_committed_as) < allowed)
>   		return 0;

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