From: Dave Hansen <dave.hansen@intel.com>
To: Wei Xu <weixugc@google.com>, Oscar Salvador <osalvador@suse.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Linux MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Yang Shi <shy828301@gmail.com>,
David Rientjes <rientjes@google.com>,
Huang Ying <ying.huang@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
David Hildenbrand <david@redhat.com>
Subject: Re: [PATCH 02/10] mm/numa: automatically generate node migration order
Date: Thu, 15 Apr 2021 08:35:09 -0700 [thread overview]
Message-ID: <6215a690-d14a-de7e-72cb-1aa4e2822f2e@intel.com> (raw)
In-Reply-To: <CAAPL-u-w_WShb0RyXhs8koihTOPvFK_dCwB22RhzA=f9kRyqqQ@mail.gmail.com>
On 4/14/21 9:07 PM, Wei Xu wrote:
> On Wed, Apr 14, 2021 at 1:08 AM Oscar Salvador <osalvador@suse.de> wrote:
>> Fast class/memory are pictured as those nodes with CPUs, while Slow class/memory
>> are PMEM, right?
>> Then, what stands for medium class/memory?
>
> That is Dave's example. I think David's guess makes sense (HBM - fast, DRAM -
> medium, PMEM - slow). It may also be possible that we have DDR5 as fast,
> CXL-DDR4 as medium, and CXL-PMEM as slow. But the most likely use cases for
> now should be just two tiers: DRAM vs PMEM or other types of slower
> memory devices.
Yes, it would be nice to apply this to fancier tiering systems. But
DRAM/PMEM combos are out in the wild today and it's where I expect this
to be used first.
> This can help enable more flexible demotion policies to be
> configured, such as to allow a cgroup to allocate from all fast tier
> nodes, but only demote to a local slow tier node. Such a policy can
> reduce memory stranding at the fast tier (compared to if memory
> hardwall is used) and still allow demotion from all fast tier nodes
> without incurring the expensive random accesses to the demoted pages
> if they were demoted to remote slow tier nodes.
Could you explain this stranding effect in a bit more detail? I'm not
quite following.
next prev parent reply other threads:[~2021-04-15 15:35 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 18:32 [PATCH 00/10] [v7][RESEND] Migrate Pages in lieu of discard Dave Hansen
2021-04-01 18:32 ` [PATCH 01/10] mm/numa: node demotion data structure and lookup Dave Hansen
2021-04-08 8:03 ` Oscar Salvador
2021-04-08 21:29 ` Dave Hansen
2021-04-09 5:32 ` Wei Xu
2021-04-01 18:32 ` [PATCH 02/10] mm/numa: automatically generate node migration order Dave Hansen
2021-04-08 8:26 ` Oscar Salvador
2021-04-08 21:51 ` Dave Hansen
2021-04-09 8:17 ` Oscar Salvador
2021-04-10 3:07 ` Wei Xu
2021-04-14 8:08 ` Oscar Salvador
2021-04-14 8:11 ` Oscar Salvador
2021-04-14 8:12 ` David Hildenbrand
2021-04-14 8:14 ` Oscar Salvador
2021-04-14 8:20 ` David Hildenbrand
2021-04-15 4:07 ` Wei Xu
2021-04-15 15:35 ` Dave Hansen [this message]
2021-04-15 20:25 ` Wei Xu
2021-04-01 18:32 ` [PATCH 03/10] mm/migrate: update node demotion order during on hotplug events Dave Hansen
2021-04-08 9:52 ` Oscar Salvador
2021-04-09 10:14 ` Oscar Salvador
2021-04-09 10:15 ` Oscar Salvador
2021-04-09 18:59 ` David Hildenbrand
2021-04-12 7:19 ` Oscar Salvador
2021-04-12 9:19 ` David Hildenbrand
2021-04-01 18:32 ` [PATCH 04/10] mm/migrate: make migrate_pages() return nr_succeeded Dave Hansen
2021-04-01 22:39 ` Wei Xu
[not found] ` <CAAPL-u-o-M2T25xBtSoipYjUnu+3aJNcJ9uS84yKaAnbrXpefw@mail.gmail.com>
2021-04-01 23:21 ` Dave Hansen
2021-04-08 10:14 ` Oscar Salvador
2021-04-08 17:26 ` Yang Shi
2021-04-08 18:17 ` Oscar Salvador
2021-04-08 18:21 ` Oscar Salvador
2021-04-08 20:40 ` Yang Shi
2021-04-09 5:06 ` Oscar Salvador
2021-04-09 5:43 ` Wei Xu
2021-04-09 15:43 ` Yang Shi
2021-04-09 15:50 ` Dave Hansen
2021-04-09 18:47 ` Wei Xu
2021-04-09 20:10 ` Yang Shi
2021-04-01 18:32 ` [PATCH 05/10] mm/migrate: demote pages during reclaim Dave Hansen
2021-04-01 20:01 ` Yang Shi
2021-04-01 22:58 ` Dave Hansen
2021-04-08 10:47 ` Oscar Salvador
2021-04-10 3:35 ` Wei Xu
2021-04-01 18:32 ` [PATCH 06/10] mm/vmscan: add page demotion counter Dave Hansen
2021-04-10 3:40 ` Wei Xu
2021-04-01 18:32 ` [PATCH 07/10] mm/vmscan: add helper for querying ability to age anonymous pages Dave Hansen
2021-04-07 18:40 ` Wei Xu
2021-04-09 8:31 ` Oscar Salvador
2021-04-01 18:32 ` [PATCH 08/10] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2021-04-02 0:55 ` Wei Xu
2021-04-01 18:32 ` [PATCH 09/10] mm/vmscan: never demote for memcg reclaim Dave Hansen
2021-04-02 0:18 ` Wei Xu
2021-04-01 18:32 ` [PATCH 10/10] mm/migrate: new zone_reclaim_mode to enable reclaim migration Dave Hansen
2021-04-01 20:06 ` Yang Shi
2021-04-10 4:10 ` Wei Xu
2021-04-16 12:35 ` [PATCH 00/10] [v7][RESEND] Migrate Pages in lieu of discard Michal Hocko
2021-04-16 14:26 ` Dave Hansen
2021-04-16 15:02 ` Michal Hocko
2021-04-21 2:39 ` Huang, Ying
2021-05-07 6:14 ` Huang, Ying
2021-06-11 5:50 ` Huang, Ying
-- strict thread matches above, loose matches on Subject: below --
2021-03-04 23:59 [PATCH 00/10] [v6] " Dave Hansen
2021-03-04 23:59 ` [PATCH 02/10] mm/numa: automatically generate node migration order Dave Hansen
2021-03-08 23:59 ` Yang Shi
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