From: Fengguang Wu <fengguang.wu@intel.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Yang Shi <yang.shi@linux.alibaba.com>,
mgorman@techsingularity.net, riel@surriel.com,
hannes@cmpxchg.org, akpm@linux-foundation.org,
dave.hansen@intel.com, keith.busch@intel.com,
dan.j.williams@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, 1 May 2019 13:20:31 +0800 [thread overview]
Message-ID: <20190501052031.dt7zbkw5n5gzf2eg@wfg-t540p.sh.intel.com> (raw)
In-Reply-To: <20190418090227.GG6567@dhcp22.suse.cz>
On Thu, Apr 18, 2019 at 11:02:27AM +0200, Michal Hocko wrote:
>On Wed 17-04-19 13:43:44, Yang Shi wrote:
>[...]
>> And, I'm wondering whether this optimization is also suitable to general
>> NUMA balancing or not.
>
>If there are convincing numbers then this should be a preferable way to
>deal with it. Please note that the number of promotions is not the only
>metric to watch. The overal performance/access latency would be another one.
Good question. Shi and me aligned today. Also talked with Mel (but
sorry I must missed some points due to poor English listening). It
becomes clear that
1) PMEM/DRAM page promotion/demotion is a hard problem to attack.
There will and should be multiple approaches for open discussion
before settling down. The criteria might be balanced complexity,
overheads, performance, etc.
2) We need a lot more data to lay solid foundation for effective
discussions. Testing will be a rather time consuming part for
contributor. We'll need to work together to create a number of
benchmarks that can well exercise the kernel promotion/demotion paths
and gather the necessary numbers. By collaborating on a common set of
tests, we can not only amortize efforts, but also compare different
approaches or compare v1/v2/... of the same approach conveniently.
Ying has already created several LKP test cases for that purpose.
Shi and me plan to join the efforts, too.
Thanks,
Fengguang
prev parent reply other threads:[~2019-05-01 5:20 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
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 [this message]
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