From: "Huang\, Ying" <ying.huang@intel.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "Huang, Ying" <ying.huang@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
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,
Andrea Arcangeli <aarcange@redhat.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Hugh Dickins <hughd@google.com>, Shaohua Li <shli@kernel.org>,
Minchan Kim <minchan@kernel.org>, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH -v3 05/10] mm, THP, swap: Add get_huge_swap_page()
Date: Thu, 08 Sep 2016 10:22:01 -0700 [thread overview]
Message-ID: <87d1ketih2.fsf@yhuang-mobile.sh.intel.com> (raw)
In-Reply-To: <20160908111353.GD17331@node> (Kirill A. Shutemov's message of "Thu, 8 Sep 2016 14:13:53 +0300")
"Kirill A. Shutemov" <kirill@shutemov.name> writes:
> On Wed, Sep 07, 2016 at 09:46:04AM -0700, Huang, Ying wrote:
>> From: Huang Ying <ying.huang@intel.com>
>>
>> A variation of get_swap_page(), get_huge_swap_page(), is added to
>> allocate a swap cluster (512 swap slots) based on the swap cluster
>> allocation function. A fair simple algorithm is used, that is, only the
>> first swap device in priority list will be tried to allocate the swap
>> cluster. The function will fail if the trying is not successful, and
>> the caller will fallback to allocate a single swap slot instead. This
>> works good enough for normal cases.
>
> For normal cases, yes. But the limitation is not obvious for users and
> performance difference after small change in configuration could be
> puzzling.
If the difference of the number of the free swap clusters among
multiple swap devices is significant, it is possible that some THP are
split earlier than necessary because we fail to allocate the swap
clusters for them. For example, this could be caused by big size
difference among multiple swap devices.
> At least this must be documented somewhere.
I can add the above description in the patch description. Any other
places do you suggest?
Best Regards,
Huang, Ying
[snip]
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next prev parent reply other threads:[~2016-09-08 17:22 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-07 16:45 [PATCH -v3 00/10] THP swap: Delay splitting THP during swapping out Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 01/10] mm, swap: Make swap cluster size same of THP size on x86_64 Huang, Ying
2016-09-08 5:45 ` Anshuman Khandual
2016-09-08 18:07 ` Huang, Ying
2016-09-19 17:09 ` Johannes Weiner
2016-09-20 2:01 ` Huang, Ying
2016-09-22 19:25 ` Johannes Weiner
2016-09-23 8:47 ` Huang, Ying
2016-09-08 8:21 ` Anshuman Khandual
2016-09-08 11:03 ` Kirill A. Shutemov
2016-09-08 17:39 ` Huang, Ying
2016-09-08 11:07 ` Kirill A. Shutemov
2016-09-08 17:23 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 02/10] mm, memcg: Add swap_cgroup_iter iterator Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 03/10] mm, memcg: Support to charge/uncharge multiple swap entries Huang, Ying
2016-09-08 5:46 ` Anshuman Khandual
2016-09-08 8:28 ` Anshuman Khandual
2016-09-08 18:15 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 04/10] mm, THP, swap: Add swap cluster allocate/free functions Huang, Ying
2016-09-08 5:49 ` Anshuman Khandual
2016-09-08 8:30 ` Anshuman Khandual
2016-09-08 18:14 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 05/10] mm, THP, swap: Add get_huge_swap_page() Huang, Ying
2016-09-08 11:13 ` Kirill A. Shutemov
2016-09-08 17:22 ` Huang, Ying [this message]
2016-09-07 16:46 ` [PATCH -v3 06/10] mm, THP, swap: Support to clear SWAP_HAS_CACHE for huge page Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 07/10] mm, THP, swap: Support to add/delete THP to/from swap cache Huang, Ying
2016-09-08 9:00 ` Anshuman Khandual
2016-09-08 18:10 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 08/10] mm, THP: Add can_split_huge_page() Huang, Ying
2016-09-08 11:17 ` Kirill A. Shutemov
2016-09-08 17:02 ` Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 09/10] mm, THP, swap: Support to split THP in swap cache Huang, Ying
2016-09-07 16:46 ` [PATCH -v3 10/10] mm, THP, swap: Delay splitting THP during swap out Huang, Ying
2016-09-09 5:43 ` [PATCH -v3 00/10] THP swap: Delay splitting THP during swapping out Minchan Kim
2016-09-09 15:53 ` Tim Chen
2016-09-09 20:35 ` Huang, Ying
2016-09-13 6:13 ` Minchan Kim
2016-09-13 6:40 ` Huang, Ying
2016-09-13 7:05 ` Minchan Kim
2016-09-13 8:53 ` Huang, Ying
2016-09-13 9:16 ` Minchan Kim
2016-09-13 23:52 ` Chen, Tim C
2016-09-19 7:11 ` Minchan Kim
2016-09-19 15:59 ` Tim Chen
2016-09-18 1:53 ` Huang, Ying
2016-09-19 7:08 ` Minchan Kim
2016-09-20 2:54 ` Huang, Ying
2016-09-20 5:06 ` Minchan Kim
2016-09-20 5:28 ` Huang, Ying
2016-09-13 14:35 ` Andrea Arcangeli
2016-09-19 17:33 ` Hugh Dickins
2016-09-22 22:56 ` Shaohua Li
2016-09-22 23:49 ` Chen, Tim C
2016-09-22 23:53 ` Andi Kleen
2016-09-23 0:38 ` Rik van Riel
2016-09-23 2:32 ` Huang, Ying
2016-09-25 19:18 ` Shaohua Li
2016-09-26 1:06 ` Minchan Kim
2016-09-26 3:25 ` Huang, Ying
2016-09-23 2:12 ` Huang, Ying
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