From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
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>,
Stephen Hemminger <sthemmin@microsoft.com>
Subject: Re: Pinning ZONE_MOVABLE pages
Date: Mon, 23 Nov 2020 12:54:16 -0500 [thread overview]
Message-ID: <CA+CK2bDx1Q5QWw=hXMs=OWwCSVrFu-xizY8YOR_MqLsvMAZm0Q@mail.gmail.com> (raw)
In-Reply-To: <20201123171502.GX244516@ziepe.ca>
On Mon, Nov 23, 2020 at 12:15 PM Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> 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.
You are right. No need for the madvise() flag at all. (The slight
difference of being able to mark memory pinned prior to touching is
really insignificant).
>
> 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.
That is right, as the first step we could just do fault and immediate
migration, which is silly, but still better than what we have now.
>
> Jason
next prev parent reply other threads:[~2020-11-23 17:54 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-20 20:27 Pinning ZONE_MOVABLE pages 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
2020-11-23 17:54 ` Pavel Tatashin [this message]
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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