From: Mel Gorman <mgorman@techsingularity.net>
To: David Hildenbrand <david@redhat.com>
Cc: Dave Hansen <dave.hansen@intel.com>,
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 11:09:18 +0100 [thread overview]
Message-ID: <20210528100918.GM30378@techsingularity.net> (raw)
In-Reply-To: <6c189def-11cc-80db-0fde-56aa506cfdea@redhat.com>
On Fri, May 28, 2021 at 11:52:53AM +0200, David Hildenbrand wrote:
> > > "Disable pcplists so that page isolation cannot race with freeing
> > > in a way that pages from isolated pageblock are left on pcplists."
> > >
> > > Guess we'd then want to move the draining before start_isolate_page_range()
> > > in alloc_contig_range().
> > >
> >
> > Or instead of draining, validate the PFN range in alloc_contig_range
> > is within the same zone and if so, call zone_pcp_disable() before
> > start_isolate_page_range and enable after __alloc_contig_migrate_range.
> >
>
> We require the caller to only pass a range within a single zone, so that
> should be fine.
>
> The only ugly thing about zone_pcp_disable() is
> mutex_lock(&pcp_batch_high_lock) which would serialize all
> alloc_contig_range() and even with offline_pages().
>
True so it would have to be accessed if that is bad or not. If racing
against offline_pages, memory is potentially being offlined in the
target zone which may cause allocation failure. If racing with other
alloc_contig_range calls, the two callers are potentially racing to
isolate and allocate the same range. The arguement could be made that
alloc_contig_ranges should be serialised within one zone to improve the
allocation success rate at the potential cost of allocation latency.
--
Mel Gorman
SUSE Labs
next prev parent reply other threads:[~2021-05-28 10:09 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-25 8:01 [PATCH 0/6 v2] Calculate pcp->high based on zone sizes and active CPUs 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 [this message]
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
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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