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From: Mel Gorman <mgorman@suse.de>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Michal Hocko <mhocko@suse.com>, Rik van Riel <riel@redhat.com>,
	Ingo Molnar <mingo@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Fengguang Wu <fengguang.wu@intel.com>
Subject: Re: [RFC 01/10] autonuma: Fix watermark checking in migrate_balanced_pgdat()
Date: Fri, 1 Nov 2019 11:11:45 +0000	[thread overview]
Message-ID: <20191101111145.GN28938@suse.de> (raw)
In-Reply-To: <20191101075727.26683-2-ying.huang@intel.com>

On Fri, Nov 01, 2019 at 03:57:18PM +0800, Huang, Ying wrote:
> From: Huang Ying <ying.huang@intel.com>
> 
> When zone_watermark_ok() is called in migrate_balanced_pgdat() to
> check migration target node, the parameter classzone_idx (for
> requested zone) is specified as 0 (ZONE_DMA).  But when allocating
> memory for autonuma in alloc_misplaced_dst_page(), the requested zone
> from GFP flags is ZONE_MOVABLE.  That is, the requested zone is
> different.  The size of lowmem_reserve for the different requested
> zone is different.  And this may cause some issues.
> 
> For example, in the zoneinfo of a test machine as below,
> 
> Node 0, zone    DMA32
>   pages free     61592
>         min      29
>         low      454
>         high     879
>         spanned  1044480
>         present  442306
>         managed  425921
>         protection: (0, 0, 62457, 62457, 62457)
> 
> The free page number of ZONE_DMA32 is greater than "high watermark +
> lowmem_reserve[ZONE_DMA]", but less than "high watermark +
> lowmem_reserve[ZONE_MOVABLE]".  And because __alloc_pages_node() in
> alloc_misplaced_dst_page() requests ZONE_MOVABLE, the
> zone_watermark_ok() on ZONE_DMA32 in migrate_balanced_pgdat() may
> always return true.  So, autonuma may not stop even when memory
> pressure in node 0 is heavy.
> 
> To fix the issue, ZONE_MOVABLE is used as parameter to call
> zone_watermark_ok() in migrate_balanced_pgdat().  This makes it same
> as requested zone in alloc_misplaced_dst_page().  So that
> migrate_balanced_pgdat() returns false when memory pressure is heavy.
> 
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>

Acked-by: Mel Gorman <mgorman@suse.de>

This patch is independent of the series and should be resent separately.
Alternatively Andrew, please pick this patch up on its own.

-- 
Mel Gorman
SUSE Labs


  reply	other threads:[~2019-11-01 11:11 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-01  7:57 [RFC 00/10] autonuma: Optimize memory placement in memory tiering system Huang, Ying
2019-11-01  7:57 ` [RFC 01/10] autonuma: Fix watermark checking in migrate_balanced_pgdat() Huang, Ying
2019-11-01 11:11   ` Mel Gorman [this message]
2019-11-01  7:57 ` [RFC 02/10] autonuma: Reduce cache footprint when scanning page tables Huang, Ying
2019-11-01 11:13   ` Mel Gorman
2019-11-01  7:57 ` [RFC 03/10] autonuma: Add NUMA_BALANCING_MEMORY_TIERING mode Huang, Ying
2019-11-01  7:57 ` [RFC 04/10] autonuma, memory tiering: Rate limit NUMA migration throughput Huang, Ying
2019-11-01  7:57 ` [RFC 05/10] autonuma, memory tiering: Use kswapd to demote cold pages to PMEM Huang, Ying
2019-11-01  7:57 ` [RFC 06/10] autonuma, memory tiering: Skip to scan fastest memory Huang, Ying
2019-11-01  7:57 ` [RFC 07/10] autonuma, memory tiering: Only promote page if accessed twice Huang, Ying
2019-11-01  7:57 ` [RFC 08/10] autonuma, memory tiering: Select hotter pages to promote to fast memory node Huang, Ying
2019-11-01  9:24   ` Peter Zijlstra
2019-11-04  2:41     ` Huang, Ying
2019-11-04  8:44       ` Peter Zijlstra
2019-11-04 10:13         ` Huang, Ying
2019-11-01  7:57 ` [RFC 09/10] autonuma, memory tiering: Double hot threshold for write hint page fault Huang, Ying
2019-11-01  7:57 ` [RFC 10/10] autonuma, memory tiering: Adjust hot threshold automatically Huang, Ying
2019-11-01  9:31   ` Peter Zijlstra
2019-11-04  6:11     ` Huang, Ying
2019-11-04  8:49       ` Peter Zijlstra
2019-11-04 10:12         ` Huang, Ying
2019-11-21  8:38         ` Huang, Ying

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