From: Pavel Tatashin <pasha.tatashin@soleen.com>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>, Michal Hocko <mhocko@suse.com>,
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>,
mike.kravetz@oracle.com, Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Mel Gorman <mgorman@suse.de>,
Matthew Wilcox <willy@infradead.org>,
David Rientjes <rientjes@google.com>,
John Hubbard <jhubbard@nvidia.com>,
Linux Doc Mailing List <linux-doc@vger.kernel.org>,
Ira Weiny <ira.weiny@intel.com>,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v6 12/14] mm/gup: longterm pin migration cleaup
Date: Wed, 20 Jan 2021 09:17:57 -0500 [thread overview]
Message-ID: <CA+CK2bCb6A19X+fHL=ZB8EuA25rh3iNL4qkL5EDZBT1XTs-dpg@mail.gmail.com> (raw)
In-Reply-To: <20210120131937.GG4605@ziepe.ca>
On Wed, Jan 20, 2021 at 8:19 AM Jason Gunthorpe <jgg@ziepe.ca> wrote:
>
> On Tue, Jan 19, 2021 at 08:43:31PM -0500, Pavel Tatashin wrote:
> > When pages are longterm pinned, we must migrated them out of movable zone.
> > The function that migrates them has a hidden loop with goto. The loop is
> > to retry on isolation failures, and after successful migration.
> >
> > Make this code better by moving this loop to the caller.
> >
> > Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
> > mm/gup.c | 88 +++++++++++++++++++++++---------------------------------
> > 1 file changed, 36 insertions(+), 52 deletions(-)
>
> This looks OK, it is better
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
>
> I really dislike we always have to go over the page list twice in pin
> mode
I agree, I also dislike that we have to loop twice.
>
> The is_pinnable_page() and LRU isolation should really be done inside
> __get_user_pages_locked() as each page is added to the output list
>
> But that is more of a larger issue than this series
We could also think about adding some optimization flags, i.e. clients
could tell gup that the pinned memory content can be discarded
FOLL_DISCARD. That way we could always allocate new pages in the right
zones as we do with this series and free existing translations. No
migration check would be necessary with such a flag.
>
> Jason
next prev parent reply other threads:[~2021-01-20 14:28 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 1:43 [PATCH v6 00/14] prohibit pinning pages in ZONE_MOVABLE Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 01/14] mm/gup: don't pin migrated cma pages in movable zone Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 02/14] mm/gup: check every subpage of a compound page during isolation Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 03/14] mm/gup: return an error on migration failure Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 04/14] mm/gup: check for isolation errors Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 05/14] mm cma: rename PF_MEMALLOC_NOCMA to PF_MEMALLOC_PIN Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 06/14] mm: apply per-task gfp constraints in fast path Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 07/14] mm: honor PF_MEMALLOC_PIN for all movable pages Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 08/14] mm/gup: do not migrate zero page Pavel Tatashin
2021-01-20 13:14 ` Jason Gunthorpe
2021-01-20 14:26 ` Pavel Tatashin
2021-01-20 14:26 ` Pavel Tatashin
2021-01-25 14:28 ` Jason Gunthorpe
2021-01-25 15:38 ` Pavel Tatashin
2021-01-25 15:38 ` Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 09/14] mm/gup: migrate pinned pages out of movable zone Pavel Tatashin
2021-01-20 17:50 ` kernel test robot
2021-01-20 17:50 ` kernel test robot
2021-01-20 21:31 ` Pavel Tatashin
2021-01-20 21:31 ` Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 10/14] memory-hotplug.rst: add a note about ZONE_MOVABLE and page pinning Pavel Tatashin
2021-01-20 13:22 ` Jason Gunthorpe
2021-01-20 14:28 ` Pavel Tatashin
2021-01-20 14:28 ` Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 11/14] mm/gup: change index type to long as it counts pages Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 12/14] mm/gup: longterm pin migration cleaup Pavel Tatashin
2021-01-20 13:19 ` Jason Gunthorpe
2021-01-20 14:17 ` Pavel Tatashin [this message]
2021-01-20 14:17 ` Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 13/14] selftests/vm: test flag is broken Pavel Tatashin
2021-01-20 1:43 ` [PATCH v6 14/14] selftests/vm: test faulting in kernel, and verify pinnable pages Pavel Tatashin
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