Re: [PATCH -mm -v6 2/9] mm, memcg: Support to charge/uncharge multiple swap entries

From	Balbir Singh <bsingharora@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH -mm -v6 2/9] mm, memcg: Support to charge/uncharge multiple swap entries
Date	2017-03-09 22:30 +0100
Message-ID	<tjdNf-2mg-15@gated-at.bofh.it> (permalink)
References	<tiEmt-3cd-5@gated-at.bofh.it> <tiEmt-3cd-21@gated-at.bofh.it> <tiIgp-5ZP-5@gated-at.bofh.it> <tiVdE-6ny-17@gated-at.bofh.it>
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On Thu, Mar 9, 2017 at 12:28 PM, Huang, Ying <ying.huang@intel.com> wrote:
> Balbir Singh <bsingharora@gmail.com> writes:
>
>> On Wed, 2017-03-08 at 15:26 +0800, Huang, Ying wrote:
>>> From: Huang Ying <ying.huang@intel.com>
>>>
>>> This patch make it possible to charge or uncharge a set of continuous
>>> swap entries in the swap cgroup.  The number of swap entries is
>>> specified via an added parameter.
>>>
>>> This will be used for the THP (Transparent Huge Page) swap support.
>>> Where a swap cluster backing a THP may be allocated and freed as a
>>> whole.  So a set of (HPAGE_PMD_NR) continuous swap entries backing one
>>> THP need to be charged or uncharged together.  This will batch the
>>> cgroup operations for the THP swap too.
>>
>> A quick look at the patches makes it look sane. I wonder if we would
>> make sense to track THP swapout separately as well
>> (from a memory.stat perspective)
>
> The patchset is just the first step of THP swap optimization.  So the
> THP will still be split after putting the THP into the swap cache.  This
> makes it unnecessary to change mem_cgroup_swapout().  I am working on a
> following up patchset to further delaying THP splitting after swapping
> out the THP to the disk.  In that patchset, I will change
> mem_cgroup_swapout() too.


Fair enough

Thanks,
Balbir

Thread

[PATCH -v6 0/9] THP swap: Delay splitting THP during swapping out "Huang, Ying" <ying.huang@intel.com> - 2017-03-08 08:40 +0100
  [PATCH -mm -v6 5/9] mm, THP, swap: Support to clear SWAP_HAS_CACHE for huge page "Huang, Ying" <ying.huang@intel.com> - 2017-03-08 08:40 +0100
  [PATCH -mm -v6 2/9] mm, memcg: Support to charge/uncharge multiple swap entries "Huang, Ying" <ying.huang@intel.com> - 2017-03-08 08:40 +0100
    Re: [PATCH -mm -v6 2/9] mm, memcg: Support to charge/uncharge  multiple swap entries Balbir Singh <bsingharora@gmail.com> - 2017-03-08 12:50 +0100
      Re: [PATCH -mm -v6 2/9] mm, memcg: Support to charge/uncharge multiple swap entries "Huang\, Ying" <ying.huang@intel.com> - 2017-03-09 02:40 +0100
        Re: [PATCH -mm -v6 2/9] mm, memcg: Support to charge/uncharge  multiple swap entries Balbir Singh <bsingharora@gmail.com> - 2017-03-09 22:30 +0100
  [PATCH -mm -v6 7/9] mm, THP: Add can_split_huge_page() "Huang, Ying" <ying.huang@intel.com> - 2017-03-08 08:40 +0100
  [PATCH -mm -v6 1/9] mm, swap: Make swap cluster size same of THP size on x86_64 "Huang, Ying" <ying.huang@intel.com> - 2017-03-08 12:20 +0100
    Re: [PATCH -mm -v6 1/9] mm, swap: Make swap cluster size same of THP  size on x86_64 Matthew Wilcox <willy@infradead.org> - 2017-03-08 14:30 +0100
      Re: [PATCH -mm -v6 1/9] mm, swap: Make swap cluster size same of THP size on x86_64 "Huang\, Ying" <ying.huang@intel.com> - 2017-03-09 02:50 +0100

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