Re: [PATCH -mm -v7 2/9] mm, memcg: Support to charge/uncharge multiple swap entries

From	Johannes Weiner <hannes@cmpxchg.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH -mm -v7 2/9] mm, memcg: Support to charge/uncharge multiple swap entries
Date	2017-03-31 17:00 +0200
Message-ID	<tr6bU-5VY-29@gated-at.bofh.it> (permalink)
References	<tpS1j-2ZP-5@gated-at.bofh.it> <tpS1k-2ZP-17@gated-at.bofh.it> <tqpgC-1u5-17@gated-at.bofh.it> <tqwBr-6DQ-7@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Thu, Mar 30, 2017 at 08:53:50AM +0800, Huang, Ying wrote:
> Johannes Weiner <hannes@cmpxchg.org> writes:
> > but there doesn't seem to be a reason to
> > pass @nr_entries when we have the struct page. Why can't this function
> > just check PageTransHuge() by itself?
> 
> Because sometimes we need to charge one swap entry for a THP.  Please
> take a look at the original add_to_swap() implementation.  For a THP,
> one swap entry will be allocated and charged to the mem cgroup before
> the THP is split.  And I think it is not easy to change this, because we
> don't want to split THP if the mem cgroup for swap exceeds its limit.

I think we do. Let's continue this discussion in the 9/9 subthread.

Thread

[PATCH -mm -v7 0/9] THP swap: Delay splitting THP during swapping out "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
  [PATCH -mm -v7 6/9] mm, THP, swap: Support to add/delete THP to/from swap cache "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
  [PATCH -mm -v7 2/9] mm, memcg: Support to charge/uncharge multiple swap entries "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
    Re: [PATCH -mm -v7 2/9] mm, memcg: Support to charge/uncharge  multiple swap entries Johannes Weiner <hannes@cmpxchg.org> - 2017-03-29 19:10 +0200
      Re: [PATCH -mm -v7 2/9] mm, memcg: Support to charge/uncharge multiple swap entries "Huang\, Ying" <ying.huang@intel.com> - 2017-03-30 03:00 +0200
        Re: [PATCH -mm -v7 2/9] mm, memcg: Support to charge/uncharge  multiple swap entries Johannes Weiner <hannes@cmpxchg.org> - 2017-03-31 17:00 +0200
  [PATCH -mm -v7 4/9] mm, THP, swap: Add get_huge_swap_page() "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
    Re: [PATCH -mm -v7 4/9] mm, THP, swap: Add get_huge_swap_page() Johannes Weiner <hannes@cmpxchg.org> - 2017-03-29 19:10 +0200
      Re: [PATCH -mm -v7 4/9] mm, THP, swap: Add get_huge_swap_page() "Huang\, Ying" <ying.huang@intel.com> - 2017-03-30 06:30 +0200
        Re: [PATCH -mm -v7 4/9] mm, THP, swap: Add get_huge_swap_page() Johannes Weiner <hannes@cmpxchg.org> - 2017-03-31 17:30 +0200
          Re: [PATCH -mm -v7 4/9] mm, THP, swap: Add get_huge_swap_page() "Huang\, Ying" <ying.huang@intel.com> - 2017-04-01 05:40 +0200
  [PATCH -mm -v7 7/9] mm, THP: Add can_split_huge_page() "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
  [PATCH -mm -v7 3/9] mm, THP, swap: Add swap cluster allocate/free functions "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
  [PATCH -mm -v7 5/9] mm, THP, swap: Support to clear SWAP_HAS_CACHE for huge page "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
  [PATCH -mm -v7 9/9] mm, THP, swap: Delay splitting THP during swap out "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
    Re: [PATCH -mm -v7 9/9] mm, THP, swap: Delay splitting THP during  swap out Johannes Weiner <hannes@cmpxchg.org> - 2017-03-29 19:20 +0200
      Re: [PATCH -mm -v7 9/9] mm, THP, swap: Delay splitting THP during swap out "Huang\, Ying" <ying.huang@intel.com> - 2017-03-30 06:20 +0200
        Re: [PATCH -mm -v7 9/9] mm, THP, swap: Delay splitting THP during  swap out Johannes Weiner <hannes@cmpxchg.org> - 2017-03-31 17:00 +0200
          Re: [PATCH -mm -v7 9/9] mm, THP, swap: Delay splitting THP during swap out "Huang\, Ying" <ying.huang@intel.com> - 2017-04-01 05:00 +0200
  [PATCH -mm -v7 8/9] mm, THP, swap: Support to split THP in swap cache "Huang, Ying" <ying.huang@intel.com> - 2017-03-28 07:40 +0200
  Re: [PATCH -mm -v7 0/9] THP swap: Delay splitting THP during  swapping out Andrew Morton <akpm@linux-foundation.org> - 2017-03-29 00:20 +0200
    Re: [PATCH -mm -v7 0/9] THP swap: Delay splitting THP during swapping out "Huang\, Ying" <ying.huang@intel.com> - 2017-03-29 11:00 +0200

csiph-web