From: "Huang\, Ying" <ying.huang@intel.com>
To: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
<rientjes@google.com>, <dan.j.williams@intel.com>
Subject: Re: [RFC][PATCH 8/8] mm/numa: new reclaim mode to enable reclaim-based migration
Date: Wed, 01 Jul 2020 08:48:31 +0800 [thread overview]
Message-ID: <87mu4knjq8.fsf@yhuang-dev.intel.com> (raw)
In-Reply-To: <29c67873-3cb9-e121-382c-9b81491016bc@linux.alibaba.com> (Yang Shi's message of "Tue, 30 Jun 2020 10:50:30 -0700")
Hi, Yang,
Yang Shi <yang.shi@linux.alibaba.com> writes:
>>> diff -puN mm/vmscan.c~enable-numa-demotion mm/vmscan.c
>>> --- a/mm/vmscan.c~enable-numa-demotion 2020-06-29 16:35:01.017312549 -0700
>>> +++ b/mm/vmscan.c 2020-06-29 16:35:01.023312549 -0700
>>> @@ -4165,9 +4165,10 @@ int node_reclaim_mode __read_mostly;
>>> * These bit locations are exposed in the vm.zone_reclaim_mode sysctl
>>> * ABI. New bits are OK, but existing bits can never change.
>>> */
>>> -#define RECLAIM_RSVD (1<<0) /* (currently ignored/unused) */
>>> -#define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */
>>> -#define RECLAIM_UNMAP (1<<2) /* Unmap pages during reclaim */
>>> +#define RECLAIM_RSVD (1<<0) /* (currently ignored/unused) */
>>> +#define RECLAIM_WRITE (1<<1) /* Writeout pages during reclaim */
>>> +#define RECLAIM_UNMAP (1<<2) /* Unmap pages during reclaim */
>>> +#define RECLAIM_MIGRATE (1<<3) /* Migrate pages during reclaim */
>>> /*
>>> * Priority for NODE_RECLAIM. This determines the fraction of pages
>> I found that RECLAIM_MIGRATE is defined but never referenced in the
>> patch.
>>
>> If my understanding of the code were correct, shrink_do_demote_mapping()
>> is called by shrink_page_list(), which is used by kswapd and direct
>> reclaim. So as long as the persistent memory node is onlined,
>> reclaim-based migration will be enabled regardless of node reclaim mode.
>
> It looks so according to the code. But the intention of a new node
> reclaim mode is to do migration on reclaim *only when* the
> RECLAIM_MODE is enabled by the users.
>
> It looks the patch just clear the migration target node masks if the
> memory is offlined.
>
> So, I'm supposed you need check if node_reclaim is enabled before
> doing migration in shrink_page_list() and also need make node reclaim
> to adopt the new mode.
But why shouldn't we migrate in kswapd and direct reclaim? I think that
we may need a way to control it, but shouldn't disable it
unconditionally.
> Please refer to
> https://lore.kernel.org/linux-mm/1560468577-101178-6-git-send-email-yang.shi@linux.alibaba.com/
>
Best Regards,
Huang, Ying
next prev parent reply other threads:[~2020-07-01 0:48 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-29 23:45 [RFC][PATCH 0/8] Migrate Pages in lieu of discard Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-29 23:45 ` [RFC][PATCH 1/8] mm/numa: node demotion data structure and lookup Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-29 23:45 ` [RFC][PATCH 2/8] mm/migrate: Defer allocating new page until needed Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-07-01 8:47 ` Greg Thelen
2020-07-01 8:47 ` Greg Thelen
2020-07-01 14:46 ` Dave Hansen
2020-07-01 18:32 ` Yang Shi
2020-06-29 23:45 ` [RFC][PATCH 3/8] mm/vmscan: Attempt to migrate page in lieu of discard Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-07-01 0:47 ` David Rientjes
2020-07-01 0:47 ` David Rientjes
2020-07-01 1:29 ` Yang Shi
2020-07-01 5:41 ` David Rientjes
2020-07-01 5:41 ` David Rientjes
2020-07-01 8:54 ` Huang, Ying
2020-07-01 8:54 ` Huang, Ying
2020-07-01 18:20 ` Dave Hansen
2020-07-01 19:50 ` David Rientjes
2020-07-01 19:50 ` David Rientjes
2020-07-02 1:50 ` Huang, Ying
2020-07-02 1:50 ` Huang, Ying
2020-07-01 15:15 ` Dave Hansen
2020-07-01 17:21 ` Yang Shi
2020-07-01 19:45 ` David Rientjes
2020-07-01 19:45 ` David Rientjes
2020-07-02 10:02 ` Jonathan Cameron
2020-07-01 1:40 ` Huang, Ying
2020-07-01 1:40 ` Huang, Ying
2020-07-01 16:48 ` Dave Hansen
2020-07-01 19:25 ` David Rientjes
2020-07-01 19:25 ` David Rientjes
2020-07-02 5:02 ` Huang, Ying
2020-07-02 5:02 ` Huang, Ying
2020-06-29 23:45 ` [RFC][PATCH 4/8] mm/vmscan: add page demotion counter Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-29 23:45 ` [RFC][PATCH 5/8] mm/numa: automatically generate node migration order Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-30 8:22 ` Huang, Ying
2020-06-30 8:22 ` Huang, Ying
2020-07-01 18:23 ` Dave Hansen
2020-07-02 1:20 ` Huang, Ying
2020-07-02 1:20 ` Huang, Ying
2020-06-29 23:45 ` [RFC][PATCH 6/8] mm/vmscan: Consider anonymous pages without swap Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-29 23:45 ` [RFC][PATCH 7/8] mm/vmscan: never demote for memcg reclaim Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-29 23:45 ` [RFC][PATCH 8/8] mm/numa: new reclaim mode to enable reclaim-based migration Dave Hansen
2020-06-29 23:45 ` Dave Hansen
2020-06-30 7:23 ` Huang, Ying
2020-06-30 7:23 ` Huang, Ying
2020-06-30 17:50 ` Yang Shi
2020-07-01 0:48 ` Huang, Ying [this message]
2020-07-01 0:48 ` Huang, Ying
2020-07-01 1:12 ` Yang Shi
2020-07-01 1:28 ` Huang, Ying
2020-07-01 1:28 ` Huang, Ying
2020-07-01 16:02 ` Dave Hansen
2020-07-03 9:30 ` Huang, Ying
2020-07-03 9:30 ` Huang, Ying
2020-06-30 18:36 ` [RFC][PATCH 0/8] Migrate Pages in lieu of discard Shakeel Butt
2020-06-30 18:36 ` Shakeel Butt
2020-06-30 18:51 ` Dave Hansen
2020-06-30 19:25 ` Shakeel Butt
2020-06-30 19:25 ` Shakeel Butt
2020-06-30 19:31 ` Dave Hansen
2020-07-01 14:24 ` [RFC] [PATCH " Zi Yan
2020-07-01 14:32 ` Dave Hansen
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