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From: Dave Hansen <dave.hansen@intel.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Hillf Danton <hdanton@sina.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Michal Hocko <mhocko@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Linux-MM <linux-mm@kvack.org>, "Tang, Feng" <feng.tang@intel.com>
Subject: Re: [PATCH 0/6 v2] Calculate pcp->high based on zone sizes and active CPUs
Date: Fri, 28 May 2021 07:39:29 -0700	[thread overview]
Message-ID: <893ce8ed-df14-612b-693f-48c9dac0eb19@intel.com> (raw)
In-Reply-To: <20210528085545.GJ30378@techsingularity.net>

On 5/28/21 1:55 AM, Mel Gorman wrote:
> -	 * onlined.
> -	 */
> -	nr_local_cpus = max(1U, cpumask_weight(cpumask_of_node(zone_to_nid(zone)))) + cpu_online;
> -	high = total_pages / nr_local_cpus;
> +	 * onlined. For memory nodes that have no CPUs, split pcp->high across
> +	 * all online CPUs to mitigate the risk that reclaim is triggered
> +	 * prematurely due to pages stored on pcp lists.
> +	 */
> +	nr_split_cpus = cpumask_weight(cpumask_of_node(zone_to_nid(zone))) + cpu_online;
> +	if (!nr_split_cpus)
> +		nr_split_cpus = num_online_cpus();
> +	high = total_pages / nr_split_cpus;

Updated version looks fine to me, thanks!

BTW, to do some of this testing, Feng was doing a plain old kernel
build.  On the one system where this got run, he noted a ~2% regression
in build times.  Nothing major, but you might want to be on the lookout
in case 0day or the other test harnesses find something similar once
this series gets to them.

Acked-by: Dave Hansen <dave.hansen@intel.com>

  parent reply	other threads:[~2021-05-28 14:39 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-25  8:01 Mel Gorman
2021-05-25  8:01 ` [PATCH 1/6] mm/page_alloc: Delete vm.percpu_pagelist_fraction Mel Gorman
2021-05-26 17:41   ` Vlastimil Babka
2021-05-25  8:01 ` [PATCH 2/6] mm/page_alloc: Disassociate the pcp->high from pcp->batch Mel Gorman
2021-05-26 18:14   ` Vlastimil Babka
2021-05-27 10:52     ` Mel Gorman
2021-05-28 10:27       ` Vlastimil Babka
2021-05-25  8:01 ` [PATCH 3/6] mm/page_alloc: Adjust pcp->high after CPU hotplug events Mel Gorman
2021-05-28 11:08   ` Vlastimil Babka
2021-05-25  8:01 ` [PATCH 4/6] mm/page_alloc: Scale the number of pages that are batch freed Mel Gorman
2021-05-28 11:19   ` Vlastimil Babka
2021-05-25  8:01 ` [PATCH 5/6] mm/page_alloc: Limit the number of pages on PCP lists when reclaim is active Mel Gorman
2021-05-28 11:43   ` Vlastimil Babka
2021-05-25  8:01 ` [PATCH 6/6] mm/page_alloc: Introduce vm.percpu_pagelist_high_fraction Mel Gorman
2021-05-28 11:59   ` Vlastimil Babka
2021-05-28 12:53     ` Mel Gorman
2021-05-28 14:38       ` Vlastimil Babka
2021-05-27 19:36 ` [PATCH 0/6 v2] Calculate pcp->high based on zone sizes and active CPUs Dave Hansen
2021-05-28  8:55   ` Mel Gorman
2021-05-28  9:03     ` David Hildenbrand
2021-05-28  9:08       ` David Hildenbrand
2021-05-28  9:49         ` Mel Gorman
2021-05-28  9:52           ` David Hildenbrand
2021-05-28 10:09             ` Mel Gorman
2021-05-28 10:21               ` David Hildenbrand
2021-05-28 12:12     ` Vlastimil Babka
2021-05-28 12:37       ` Mel Gorman
2021-05-28 14:39     ` Dave Hansen [this message]
2021-05-28 15:18       ` Mel Gorman
2021-05-28 16:17         ` Dave Hansen
2021-05-31 12:00           ` Feng Tang

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