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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: Tue, 16 Apr 2019 20:34:04 +0200	[thread overview]
Message-ID: <20190416183404.GA655@dhcp22.suse.cz> (raw)
In-Reply-To: <bddc3469-2984-2d32-f2cf-e1d0cc64f1e8@intel.com>

On Tue 16-04-19 08:46:56, Dave Hansen wrote:
> On 4/16/19 7:39 AM, Michal Hocko wrote:
> >> Strict binding also doesn't keep another app from moving the
> >> memory.
> > I would consider that a bug.
> 
> A bug where, though?  Certainly not in the kernel.

Kernel should refrain from moving explicitly bound memory nilly willy. I
certainly agree that there are corner cases. E.g. memory hotplug. We do
break CPU affinity for CPU offline as well. So this is something user
should expect. But the kernel shouldn't move explicitly bound pages to a
different node implicitly. I am not sure whether we even do that during
compaction if we do then I would consider _this_ to be a bug. And NUMA
rebalancing under memory pressure falls into the same category IMO.
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2019-04-16 18:34 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 [this message]
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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