linux-kernel - Re: [PATCH v2] mm: vmscan: fix the page state calculation in too_many

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <54BA8DEC.1080508@codeaurora.org>
Date:	Sat, 17 Jan 2015 21:59:32 +0530
From:	Vinayak Menon <vinmenon@...eaurora.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
CC:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	hannes@...xchg.org, vdavydov@...allels.com, mhocko@...e.cz,
	mgorman@...e.de, minchan@...nel.org
Subject: Re: [PATCH v2] mm: vmscan: fix the page state calculation in too_many_isolated

On 01/16/2015 06:47 AM, Andrew Morton wrote:

> From: Andrew Morton <akpm@...ux-foundation.org>
> Subject: mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fix
>
> Move the zone_page_state_snapshot() fallback logic into
> too_many_isolated(), so shrink_inactive_list() doesn't incorrectly call
> congestion_wait().
>
> Cc: Johannes Weiner <hannes@...xchg.org>
> Cc: Mel Gorman <mgorman@...e.de>
> Cc: Michal Hocko <mhocko@...e.cz>
> Cc: Minchan Kim <minchan@...nel.org>
> Cc: Vinayak Menon <vinmenon@...eaurora.org>
> Cc: Vladimir Davydov <vdavydov@...allels.com>
> Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
> ---
>
>   mm/vmscan.c |   23 +++++++++++------------
>   1 file changed, 11 insertions(+), 12 deletions(-)
>
> diff -puN mm/vmscan.c~mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fix mm/vmscan.c
> --- a/mm/vmscan.c~mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated-fix
> +++ a/mm/vmscan.c
> @@ -1402,7 +1402,7 @@ int isolate_lru_page(struct page *page)
>   }
>
>   static int __too_many_isolated(struct zone *zone, int file,
> -	struct scan_control *sc, int safe)
> +			       struct scan_control *sc, int safe)
>   {
>   	unsigned long inactive, isolated;
>
> @@ -1435,7 +1435,7 @@ static int __too_many_isolated(struct zo
>    * unnecessary swapping, thrashing and OOM.
>    */
>   static int too_many_isolated(struct zone *zone, int file,
> -		struct scan_control *sc, int safe)
> +			     struct scan_control *sc)
>   {
>   	if (current_is_kswapd())
>   		return 0;
> @@ -1443,12 +1443,14 @@ static int too_many_isolated(struct zone
>   	if (!global_reclaim(sc))
>   		return 0;
>
> -	if (unlikely(__too_many_isolated(zone, file, sc, 0))) {
> -		if (safe)
> -			return __too_many_isolated(zone, file, sc, safe);
> -		else
> -			return 1;
> -	}
> +	/*
> +	 * __too_many_isolated(safe=0) is fast but inaccurate, because it
> +	 * doesn't account for the vm_stat_diff[] counters.  So if it looks
> +	 * like too_many_isolated() is about to return true, fall back to the
> +	 * slower, more accurate zone_page_state_snapshot().
> +	 */
> +	if (unlikely(__too_many_isolated(zone, file, sc, 0)))
> +		return __too_many_isolated(zone, file, sc, safe);

Just noticed now that, in the above statement it should be "1", instead 
of "safe". "safe" is not declared.



-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member of the Code Aurora Forum, hosted by The Linux Foundation
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/