From: Jason Gunthorpe <jgg@ziepe.ca>
To: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Michal Hocko <mhocko@suse.com>, linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
LKML <linux-kernel@vger.kernel.org>,
David Hildenbrand <david@redhat.com>,
Oscar Salvador <osalvador@suse.de>,
Dan Williams <dan.j.williams@intel.com>,
Sasha Levin <sashal@kernel.org>,
Tyler Hicks <tyhicks@linux.microsoft.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
sthemmin@microsoft.com
Subject: Re: Pinning ZONE_MOVABLE pages
Date: Mon, 23 Nov 2020 13:15:02 -0400 [thread overview]
Message-ID: <20201123171502.GX244516@ziepe.ca> (raw)
In-Reply-To: <CA+CK2bCD8_x5cBUOksAzat_O4G8-PoLp378zN1mxKMcmyV8dAw@mail.gmail.com>
On Mon, Nov 23, 2020 at 11:06:21AM -0500, Pavel Tatashin wrote:
> What I mean here is allowing users to guarantee that the page's PA is
> going to stay the same. Sort of a stronger mlock. Mlock only
> guarantees that the page is not swapped, but something like
You've just described get/pin_user_pages(), that is exactly what it is
for.
I agree with the other emails, ZONE_MOVABLE needs to be reconciled
with FOLL_LONGTERM - most likely by preventing ZONE_MOVABLE pages from
being returned. This will need migration like CMA does and the point
about faulting is only an optimization to prevent fault then immediate
migration.
Jason
next prev parent reply other threads:[~2020-11-23 17:15 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 20:27 Pavel Tatashin
2020-11-20 20:59 ` David Hildenbrand
2020-11-20 21:17 ` Matthew Wilcox
2020-11-20 21:34 ` David Hildenbrand
2020-11-20 21:53 ` Pavel Tatashin
2020-11-20 21:58 ` Pavel Tatashin
2020-11-20 22:06 ` David Hildenbrand
2020-11-22 21:06 ` David Rientjes
2020-11-23 15:31 ` Pavel Tatashin
2020-11-23 9:01 ` Michal Hocko
2020-11-23 16:06 ` Pavel Tatashin
2020-11-23 17:15 ` Jason Gunthorpe [this message]
2020-11-23 17:54 ` Pavel Tatashin
2020-11-23 18:34 ` Jason Gunthorpe
2020-11-24 8:20 ` Michal Hocko
2020-11-23 15:04 ` Vlastimil Babka
2020-11-23 16:31 ` Pavel Tatashin
2020-11-24 8:24 ` Michal Hocko
2020-11-24 8:43 ` Michal Hocko
2020-11-24 8:44 ` David Hildenbrand
2020-11-24 6:49 ` John Hubbard
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