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From: Andrew Morton <akpm@linux-foundation.org>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: tim.c.chen@intel.com, dave.hansen@intel.com,
	andi.kleen@intel.com, aaron.lu@intel.com, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
	Shaohua Li <shli@kernel.org>, Minchan Kim <minchan@kernel.org>,
	Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH -v2 01/10] swap: Change SWAPFILE_CLUSTER to 512
Date: Thu, 1 Sep 2016 14:22:46 -0700	[thread overview]
Message-ID: <20160901142246.631fe47a558bb7522f73c034@linux-foundation.org> (raw)
In-Reply-To: <1472743023-4116-2-git-send-email-ying.huang@intel.com>

On Thu,  1 Sep 2016 08:16:54 -0700 "Huang, Ying" <ying.huang@intel.com> wrote:

> From: Huang Ying <ying.huang@intel.com>
> 
> In this patch, the size of the swap cluster is changed to that of the
> THP (Transparent Huge Page) on x86_64 architecture (512).  This is for
> the THP swap support on x86_64.  Where one swap cluster will be used to
> hold the contents of each THP swapped out.  And some information of the
> swapped out THP (such as compound map count) will be recorded in the
> swap_cluster_info data structure.
> 
> In effect,  this will enlarge swap  cluster size by 2  times.  Which may
> make  it harder  to find  a  free cluster  when the  swap space  becomes
> fragmented.   So  that,  this  may  reduce  the  continuous  swap  space
> allocation and sequential write in theory.  The performance test in 0day
> show no regressions caused by this.
> 
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -196,7 +196,7 @@ static void discard_swap_cluster(struct swap_info_struct *si,
>  	}
>  }
>  
> -#define SWAPFILE_CLUSTER	256
> +#define SWAPFILE_CLUSTER	512
>  #define LATENCY_LIMIT		256
>  

What happens to architectures which have different HPAGE_SIZE and/or
PAGE_SIZE?

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  reply	other threads:[~2016-09-01 21:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-01 15:16 [PATCH -v2 00/10] THP swap: Delay splitting THP during swapping out Huang, Ying
2016-09-01 15:16 ` [PATCH -v2 01/10] swap: Change SWAPFILE_CLUSTER to 512 Huang, Ying
2016-09-01 21:22   ` Andrew Morton [this message]
2016-09-01 23:04     ` Huang, Ying
2016-09-02 20:30       ` Andrew Morton
2016-09-02 20:37         ` Huang, Ying
2016-09-01 15:16 ` [PATCH -v2 02/10] mm, memcg: Add swap_cgroup_iter iterator Huang, Ying
2016-09-01 15:16 ` [PATCH -v2 03/10] mm, memcg: Support to charge/uncharge multiple swap entries Huang, Ying
2016-09-01 15:16 ` [PATCH -v2 04/10] mm, THP, swap: Add swap cluster allocate/free functions Huang, Ying
2016-09-01 15:16 ` [PATCH -v2 05/10] mm, THP, swap: Add get_huge_swap_page() Huang, Ying
2016-09-01 15:16 ` [PATCH -v2 06/10] mm, THP, swap: Support to clear SWAP_HAS_CACHE for huge page Huang, Ying
2016-09-01 15:17 ` [PATCH -v2 07/10] mm, THP, swap: Support to add/delete THP to/from swap cache Huang, Ying
2016-09-01 15:17 ` [PATCH -v2 08/10] mm, THP: Add can_split_huge_page() Huang, Ying
2016-09-01 15:17 ` [PATCH -v2 09/10] mm, THP, swap: Support to split THP in swap cache Huang, Ying
2016-09-01 15:17 ` [PATCH -v2 10/10] mm, THP, swap: Delay splitting THP during swap out Huang, Ying

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