From: Yang Shi <yang.shi@linux.alibaba.com>
To: Dave Hansen <dave.hansen@intel.com>,
mhocko@suse.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
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [v2 PATCH 7/9] mm: vmscan: check if the demote target node is contended or not
Date: Mon, 15 Apr 2019 15:06:27 -0700 [thread overview]
Message-ID: <5082655c-6a24-a3d7-1b7d-bb256597890c@linux.alibaba.com> (raw)
In-Reply-To: <6d40d60e-dde4-7d70-c7a8-1a444c70c3ff@intel.com>
On 4/11/19 9:06 AM, Dave Hansen wrote:
> On 4/10/19 8:56 PM, Yang Shi wrote:
>> When demoting to PMEM node, the target node may have memory pressure,
>> then the memory pressure may cause migrate_pages() fail.
>>
>> If the failure is caused by memory pressure (i.e. returning -ENOMEM),
>> tag the node with PGDAT_CONTENDED. The tag would be cleared once the
>> target node is balanced again.
>>
>> Check if the target node is PGDAT_CONTENDED or not, if it is just skip
>> demotion.
> This seems like an actively bad idea to me.
>
> Why do we need an *active* note to say the node is contended? Why isn't
> just getting a failure back from migrate_pages() enough? Have you
> observed this in practice?
The flag will be used to check if the target node is contended or not
before moving the page into the demotion list. If the target node is
contended (i.e. GFP_NOWAIT would likely fail), the page reclaim code
even won't scan anonymous page list on swapless system. It will just try
to reclaim page cache. This would save some scanning time.
Thanks,
Yang
next prev parent reply other threads:[~2019-04-15 22:06 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 [this message]
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
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