linux-kernel - Re: [PATCH v3 0/2] mm: swap: mTHP swap allocator base on swap cluster order

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Message-ID: <874j9hzqr3.fsf@yhuang6-desk2.ccr.corp.intel.com>
Date: Tue, 25 Jun 2024 10:43:28 +0800
From: "Huang, Ying" <ying.huang@...el.com>
To: Chris Li <chrisl@...nel.org>
Cc: Andrew Morton <akpm@...ux-foundation.org>,  Kairui Song
 <kasong@...cent.com>,  Ryan Roberts <ryan.roberts@....com>,  Kalesh Singh
 <kaleshsingh@...gle.com>,  linux-kernel@...r.kernel.org,
  linux-mm@...ck.org,  Barry Song <baohua@...nel.org>
Subject: Re: [PATCH v3 0/2] mm: swap: mTHP swap allocator base on swap
 cluster order

Chris Li <chrisl@...nel.org> writes:

> This is the short term solutiolns "swap cluster order" listed
> in my "Swap Abstraction" discussion slice 8 in the recent
> LSF/MM conference.
>
> When commit 845982eb264bc "mm: swap: allow storage of all mTHP
> orders" is introduced, it only allocates the mTHP swap entries
> from new empty cluster list.  It has a fragmentation issue
> reported by Barry.
>
> https://lore.kernel.org/all/CAGsJ_4zAcJkuW016Cfi6wicRr8N9X+GJJhgMQdSMp+Ah+NSgNQ@mail.gmail.com/
>
> The reason is that all the empty cluster has been exhausted while
> there are planty of free swap entries to in the cluster that is
> not 100% free.
>
> Remember the swap allocation order in the cluster.
> Keep track of the per order non full cluster list for later allocation.

The "non full" is a kind of negative naming, can we use "partial" as
that used in "slub"?

[snip]

--
Best Regards,
Huang, Ying