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From: Michal Hocko <mhocko@kernel.org>
To: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	dan.j.williams@intel.com
Subject: Re: [PATCH 0/4] [RFC] Migrate Pages in lieu of discard
Date: Fri, 18 Oct 2019 09:44:11 +0200	[thread overview]
Message-ID: <20191018074411.GC5017@dhcp22.suse.cz> (raw)
In-Reply-To: <20191016221148.F9CCD155@viggo.jf.intel.com>

On Wed 16-10-19 15:11:48, Dave Hansen wrote:
> We're starting to see systems with more and more kinds of memory such
> as Intel's implementation of persistent memory.
> 
> Let's say you have a system with some DRAM and some persistent memory.
> Today, once DRAM fills up, reclaim will start and some of the DRAM
> contents will be thrown out.  Allocations will, at some point, start
> falling over to the slower persistent memory.
> 
> That has two nasty properties.  First, the newer allocations can end
> up in the slower persistent memory.  Second, reclaimed data in DRAM
> are just discarded even if there are gobs of space in persistent
> memory that could be used.
> 
> This set implements a solution to these problems.  At the end of the
> reclaim process in shrink_page_list() just before the last page
> refcount is dropped, the page is migrated to persistent memory instead
> of being dropped.
> 
> While I've talked about a DRAM/PMEM pairing, this approach would
> function in any environment where memory tiers exist.
> 
> This is not perfect.  It "strands" pages in slower memory and never
> brings them back to fast DRAM.  Other things need to be built to
> promote hot pages back to DRAM.
> 
> This is part of a larger patch set.  If you want to apply these or
> play with them, I'd suggest using the tree from here.  It includes
> autonuma-based hot page promotion back to DRAM:
> 
> 	http://lkml.kernel.org/r/c3d6de4d-f7c3-b505-2e64-8ee5f70b2118@intel.com
> 
> This is also all based on an upstream mechanism that allows
> persistent memory to be onlined and used as if it were volatile:
> 
> 	http://lkml.kernel.org/r/20190124231441.37A4A305@viggo.jf.intel.com

How does this compare to
http://lkml.kernel.org/r/1560468577-101178-1-git-send-email-yang.shi@linux.alibaba.com?

-- 
Michal Hocko
SUSE Labs

  parent reply	other threads:[~2019-10-18  7:44 UTC|newest]

Thread overview: 48+ 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 ` Dave Hansen
2019-10-16 22:11 ` [PATCH 1/4] node: Define and export memory migration path Dave Hansen
2019-10-16 22:11   ` 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
2019-10-16 22:11   ` Dave Hansen
2019-10-17 11:27   ` Kirill A. Shutemov
2019-10-16 22:11 ` [PATCH 3/4] mm/vmscan: Attempt to migrate page in lieu of discard Dave Hansen
2019-10-16 22:11   ` Dave Hansen
2019-10-17 17:30   ` Yang Shi
2019-10-17 17:30     ` Yang Shi
2019-10-18 18:15     ` Dave Hansen
2019-10-18 21:02       ` Yang Shi
2019-10-18 21:02         ` Yang Shi
2019-10-16 22:11 ` [PATCH 4/4] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2019-10-16 22:11   ` Dave Hansen
2019-10-17  3:45 ` [PATCH 0/4] [RFC] Migrate Pages in lieu of discard Shakeel Butt
2019-10-17  3:45   ` Shakeel Butt
2019-10-17 14:26   ` Dave Hansen
2019-10-17 16:58     ` Shakeel Butt
2019-10-17 16:58       ` Shakeel Butt
2019-10-17 20:51       ` Dave Hansen
2019-10-17 17:20     ` Yang Shi
2019-10-17 17:20       ` Yang Shi
2019-10-17 21:05       ` Dave Hansen
2019-10-17 22:58       ` Shakeel Butt
2019-10-17 22:58         ` Shakeel Butt
2019-10-18 21:44         ` Yang Shi
2019-10-18 21:44           ` Yang Shi
2019-10-17 16:01 ` Suleiman Souhlal
2019-10-17 16:01   ` Suleiman Souhlal
2019-10-17 16:32   ` Dave Hansen
2019-10-17 16:39     ` Shakeel Butt
2019-10-17 16:39       ` Shakeel Butt
2019-10-18  8:11     ` Suleiman Souhlal
2019-10-18  8:11       ` Suleiman Souhlal
2019-10-18 15:10       ` Dave Hansen
2019-10-18 15:39         ` Suleiman Souhlal
2019-10-18 15:39           ` Suleiman Souhlal
2019-10-18  7:44 ` Michal Hocko [this message]
2019-10-18 14:54   ` Dave Hansen
2019-10-18 21:39     ` Yang Shi
2019-10-18 21:39       ` Yang Shi
2019-10-18 21:55       ` Dan Williams
2019-10-18 21:55         ` Dan Williams
2019-10-22 13:49     ` Michal Hocko

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