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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	dan.j.williams@intel.com, keith.busch@intel.com
Subject: Re: [PATCH 2/4] mm/migrate: Defer allocating new page until needed
Date: Thu, 17 Oct 2019 14:27:24 +0300	[thread overview]
Message-ID: <20191017112724.f74v2xqgb6swo7w7@box> (raw)
In-Reply-To: <20191016221151.854D5735@viggo.jf.intel.com>

On Wed, Oct 16, 2019 at 03:11:51PM -0700, Dave Hansen wrote:
> 
> From: Keith Busch <keith.busch@intel.com>
> 
> Migrating pages had been allocating the new page before it was actually
> needed. Subsequent operations may still fail, which would have to handle
> cleaning up the newly allocated page when it was never used.
> 
> Defer allocating the page until we are actually ready to make use of
> it, after locking the original page. This simplifies error handling,
> but should not have any functional change in behavior. This is just
> refactoring page migration so the main part can more easily be reused
> by other code.

Well, the functional change I see is that now we allocate a new page under
page lock of old page.

It *should* be fine, but it has to be call out in the commit message.

-- 
 Kirill A. Shutemov


  reply	other threads:[~2019-10-17 11:27 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-16 22:11 [PATCH 0/4] [RFC] Migrate Pages in lieu of discard Dave Hansen
2019-10-16 22:11 ` [PATCH 1/4] node: Define and export memory migration path Dave Hansen
2019-10-17 11:12   ` Kirill A. Shutemov
2019-10-17 11:44     ` Kirill A. Shutemov
2019-10-16 22:11 ` [PATCH 2/4] mm/migrate: Defer allocating new page until needed Dave Hansen
2019-10-17 11:27   ` Kirill A. Shutemov [this message]
2019-10-16 22:11 ` [PATCH 3/4] mm/vmscan: Attempt to migrate page in lieu of discard Dave Hansen
2019-10-17 17:30   ` Yang Shi
2019-10-18 18:15     ` Dave Hansen
2019-10-18 21:02       ` Yang Shi
2019-10-16 22:11 ` [PATCH 4/4] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2019-10-17  3:45 ` [PATCH 0/4] [RFC] Migrate Pages in lieu of discard Shakeel Butt
2019-10-17 14:26   ` Dave Hansen
2019-10-17 16:58     ` Shakeel Butt
2019-10-17 20:51       ` Dave Hansen
2019-10-17 17:20     ` Yang Shi
2019-10-17 21:05       ` Dave Hansen
2019-10-17 22:58       ` Shakeel Butt
2019-10-18 21:44         ` Yang Shi
2019-10-17 16:01 ` Suleiman Souhlal
2019-10-17 16:32   ` Dave Hansen
2019-10-17 16:39     ` Shakeel Butt
2019-10-18  8:11     ` Suleiman Souhlal
2019-10-18 15:10       ` Dave Hansen
2019-10-18 15:39         ` Suleiman Souhlal
2019-10-18  7:44 ` Michal Hocko
2019-10-18 14:54   ` Dave Hansen
2019-10-18 21:39     ` Yang Shi
2019-10-18 21:55       ` Dan Williams
2019-10-22 13:49     ` Michal Hocko

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