From: osalvador@suse.de
To: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Michal Hocko <mhocko@kernel.org>,
Pavel Tatashin <pasha.tatashin@soleen.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [RFC 0/5] disable pcplists during page isolation
Date: Wed, 09 Sep 2020 13:27:42 +0200 [thread overview]
Message-ID: <3f4bd7b0c73f59b4cd2adaad3ccc38bf@suse.de> (raw)
In-Reply-To: <ce8d05db-b804-21c7-0d12-43e11fc232e5@suse.cz>
On 2020-09-09 12:54, Vlastimil Babka wrote:
> Thanks! I expect no performance change while no isolation is in
> progress, as
> there are no new tests added in alloc/free paths. During page isolation
> there's
> a single drain instead of once-per-pageblock, which is a benefit. But
> the
> pcplists are effectively disabled for the whole of online_pages(),
> offline_pages() or alloc_contig_range(), which will affect parallel
> page
> allocator users. It depends on how long these operations take and how
> heavy the
> parallel usage is, so I have no good answers. Might be similar to the
> current
> periodic drain.
I have seen some systems taking quite some time when offlining sections
due to the migration of
the respective pages not being that smooth and having do_migrate_range
to do some spins.
But to be fair, online_pages and offline_pages are not routines that get
called that often, and we would be safe to assume that memory-hotplug
operations are not constantly happening, but are rather one-offs
operations.
I am not sure about Xen and HV, IIRC Xen was using online_pages and
offline_pages routines to do the ballooning?
I will dive in this in the following days, thanks for the work Vlastimil
next prev parent reply other threads:[~2020-09-09 11:27 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 16:36 [RFC 0/5] disable pcplists during page isolation Vlastimil Babka
2020-09-07 16:36 ` [RFC 1/5] mm, page_alloc: clean up pageset high and batch update Vlastimil Babka
2020-09-10 8:31 ` Oscar Salvador
2020-09-10 8:34 ` Oscar Salvador
2020-09-10 10:47 ` David Hildenbrand
2020-09-17 16:05 ` Vlastimil Babka
2020-09-07 16:36 ` [RFC 2/5] mm, page_alloc: calculate pageset high and batch once per zone Vlastimil Babka
2020-09-10 9:00 ` Oscar Salvador
2020-09-10 10:56 ` David Hildenbrand
2020-09-07 16:36 ` [RFC 3/5] mm, page_alloc(): remove setup_pageset() Vlastimil Babka
2020-09-10 9:23 ` Oscar Salvador
2020-09-10 9:57 ` Oscar Salvador
2020-09-18 9:37 ` Vlastimil Babka
2020-09-10 11:00 ` David Hildenbrand
2020-09-07 16:36 ` [RFC 4/5] mm, page_alloc: cache pageset high and batch in struct zone Vlastimil Babka
2020-09-10 11:30 ` Oscar Salvador
2020-09-18 12:02 ` Vlastimil Babka
2020-09-07 16:36 ` [RFC 5/5] mm, page_alloc: disable pcplists during page isolation Vlastimil Babka
2020-09-09 10:48 ` Vlastimil Babka
2020-09-09 11:36 ` Michal Hocko
2020-09-09 11:44 ` David Hildenbrand
2020-09-09 12:57 ` David Hildenbrand
2020-09-09 11:55 ` Vlastimil Babka
2020-09-10 10:29 ` David Hildenbrand
2020-09-10 11:05 ` Vlastimil Babka
2020-09-10 12:42 ` David Hildenbrand
2020-09-09 12:53 ` Pavel Tatashin
2020-09-08 18:29 ` [RFC 0/5] " David Hildenbrand
2020-09-09 10:54 ` Vlastimil Babka
2020-09-09 11:27 ` osalvador [this message]
2020-09-09 11:29 ` David Hildenbrand
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