linux-kernel - Re: [PATCH 1/4] vmscan: delegate pageout io to flusher thread if current is kswapd

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 for Android: free password hash cracker in your pocket

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

Date:	Thu, 15 Apr 2010 17:18:56 +0900 (JST)
From:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
To:	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
Cc:	kosaki.motohiro@...fujitsu.com, Dave Chinner <david@...morbit.com>,
	Mel Gorman <mel@....ul.ie>,
	Chris Mason <chris.mason@...cle.com>,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 1/4] vmscan: delegate pageout io to flusher thread if current is kswapd

> Now, vmscan pageout() is one of IO throuput degression source.
> Some IO workload makes very much order-0 allocation and reclaim
> and pageout's 4K IOs are making annoying lots seeks.
> 
> At least, kswapd can avoid such pageout() because kswapd don't
> need to consider OOM-Killer situation. that's no risk.

I've found one bug in this patch myself. flusher thread don't
pageout anon pages. then, we need PageAnon() check ;)



> 
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>
> ---
>  mm/vmscan.c |    7 +++++++
>  1 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 3ff3311..d392a50 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -614,6 +614,13 @@ static enum page_references page_check_references(struct page *page,
>  	if (referenced_page)
>  		return PAGEREF_RECLAIM_CLEAN;
>  
> +	/*
> +	 * Delegate pageout IO to flusher thread. They can make more
> +	 * effective IO pattern.
> +	 */
> +	if (current_is_kswapd())
> +		return PAGEREF_RECLAIM_CLEAN;
> +
>  	return PAGEREF_RECLAIM;
>  }
>  
> -- 
> 1.6.5.2
> 
> 
> 



--
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/