From: Michal Hocko <mhocko@kernel.org>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>,
mgorman@techsingularity.net, riel@surriel.com,
hannes@cmpxchg.org, akpm@linux-foundation.org,
keith.busch@intel.com, dan.j.williams@intel.com,
fengguang.wu@intel.com, fan.du@intel.com, ying.huang@intel.com,
ziy@nvidia.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [v2 RFC PATCH 0/9] Another Approach to Use PMEM as NUMA Node
Date: Wed, 17 Apr 2019 11:23:18 +0200 [thread overview]
Message-ID: <20190417092318.GG655@dhcp22.suse.cz> (raw)
In-Reply-To: <a0bf6b61-1ec2-6209-5760-80c5f205d52e@intel.com>
On Tue 16-04-19 14:22:33, Dave Hansen wrote:
> On 4/16/19 12:19 PM, Yang Shi wrote:
> > would we prefer to try all the nodes in the fallback order to find the
> > first less contended one (i.e. DRAM0 -> PMEM0 -> DRAM1 -> PMEM1 -> Swap)?
>
> Once a page went to DRAM1, how would we tell that it originated in DRAM0
> and is following the DRAM0 path rather than the DRAM1 path?
>
> Memory on DRAM0's path would be:
>
> DRAM0 -> PMEM0 -> DRAM1 -> PMEM1 -> Swap
>
> Memory on DRAM1's path would be:
>
> DRAM1 -> PMEM1 -> DRAM0 -> PMEM0 -> Swap
>
> Keith Busch had a set of patches to let you specify the demotion order
> via sysfs for fun. The rules we came up with were:
I am not a fan of any sysfs "fun"
> 1. Pages keep no history of where they have been
makes sense
> 2. Each node can only demote to one other node
Not really, see my other email. I do not really see any strong reason
why not use the full zonelist to demote to
> 3. The demotion path can not have cycles
yes. This could be achieved by GFP_NOWAIT opportunistic allocation for
the migration target. That should prevent from loops or artificial nodes
exhausting quite naturaly AFAICS. Maybe we will need some tricks to
raise the watermark but I am not convinced something like that is really
necessary.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2019-04-17 9:23 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-11 3:56 [v2 RFC PATCH 0/9] Another Approach to Use PMEM as NUMA Node Yang Shi
2019-04-11 3:56 ` [v2 PATCH 1/9] mm: define N_CPU_MEM node states Yang Shi
2019-04-11 3:56 ` [v2 PATCH 2/9] mm: page_alloc: make find_next_best_node find return cpuless node Yang Shi
2019-04-11 3:56 ` [v2 PATCH 3/9] mm: numa: promote pages to DRAM when it gets accessed twice Yang Shi
2019-04-11 3:56 ` [v2 PATCH 4/9] mm: migrate: make migrate_pages() return nr_succeeded Yang Shi
2019-04-11 3:56 ` [v2 PATCH 5/9] mm: vmscan: demote anon DRAM pages to PMEM node Yang Shi
2019-04-11 14:31 ` Dave Hansen
2019-04-15 22:10 ` Yang Shi
2019-04-15 22:14 ` Dave Hansen
2019-04-15 22:26 ` Yang Shi
2019-04-11 3:56 ` [v2 PATCH 6/9] mm: vmscan: don't demote for memcg reclaim Yang Shi
2019-04-11 3:56 ` [v2 PATCH 7/9] mm: vmscan: check if the demote target node is contended or not Yang Shi
2019-04-11 16:06 ` Dave Hansen
2019-04-15 22:06 ` Yang Shi
2019-04-15 22:13 ` Dave Hansen
2019-04-15 22:23 ` Yang Shi
2019-04-11 3:56 ` [v2 PATCH 8/9] mm: vmscan: add page demotion counter Yang Shi
2019-04-11 3:56 ` [v2 PATCH 9/9] mm: numa: add page promotion counter Yang Shi
2019-04-11 14:28 ` [v2 RFC PATCH 0/9] Another Approach to Use PMEM as NUMA Node Dave Hansen
2019-04-12 8:47 ` Michal Hocko
2019-04-16 0:09 ` Yang Shi
2019-04-16 7:47 ` Michal Hocko
2019-04-16 14:30 ` Dave Hansen
2019-04-16 14:39 ` Michal Hocko
2019-04-16 15:46 ` Dave Hansen
2019-04-16 18:34 ` Michal Hocko
2019-04-16 15:33 ` Zi Yan
2019-04-16 15:55 ` Dave Hansen
2019-04-16 16:12 ` Zi Yan
2019-04-16 19:19 ` Yang Shi
2019-04-16 21:22 ` Dave Hansen
2019-04-16 21:59 ` Yang Shi
2019-04-16 23:04 ` Dave Hansen
2019-04-16 23:17 ` Yang Shi
2019-04-17 15:13 ` Keith Busch
2019-04-17 9:23 ` Michal Hocko [this message]
2019-04-17 15:23 ` Keith Busch
2019-04-17 15:39 ` Michal Hocko
2019-04-17 15:37 ` Keith Busch
2019-04-17 16:39 ` Michal Hocko
2019-04-17 17:26 ` Yang Shi
2019-04-17 17:29 ` Keith Busch
2019-04-17 17:51 ` Michal Hocko
2019-04-18 16:24 ` Yang Shi
2019-04-17 17:13 ` Dave Hansen
2019-04-17 17:57 ` Michal Hocko
2019-04-18 18:16 ` Keith Busch
2019-04-18 19:23 ` Yang Shi
2019-04-18 21:07 ` Zi Yan
2019-04-16 23:18 ` Yang Shi
2019-04-17 9:17 ` Michal Hocko
2019-05-01 6:43 ` Fengguang Wu
2019-04-17 20:43 ` Yang Shi
2019-04-18 9:02 ` Michal Hocko
2019-05-01 5:20 ` Fengguang Wu
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