From: Yang Shi <shy828301@gmail.com>
To: Mel Gorman <mgorman@suse.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Zi Yan <ziy@nvidia.com>, Michal Hocko <mhocko@suse.com>,
Huang Ying <ying.huang@intel.com>,
Hugh Dickins <hughd@google.com>,
Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
linux-s390@vger.kernel.org,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [v2 PATCH 3/7] mm: thp: refactor NUMA fault handling
Date: Mon, 17 May 2021 12:41:11 -0700 [thread overview]
Message-ID: <CAHbLzko=2TXdx3fivtAvpUMyZAHC_sQ+eVQqf3-nR5Zz838GrQ@mail.gmail.com> (raw)
In-Reply-To: <20210517152721.GW3672@suse.de>
On Mon, May 17, 2021 at 8:27 AM Mel Gorman <mgorman@suse.de> wrote:
>
> On Tue, Apr 13, 2021 at 02:24:12PM -0700, Yang Shi wrote:
> > When the THP NUMA fault support was added THP migration was not supported yet.
> > So the ad hoc THP migration was implemented in NUMA fault handling. Since v4.14
> > THP migration has been supported so it doesn't make too much sense to still keep
> > another THP migration implementation rather than using the generic migration
> > code.
> >
> > This patch reworked the NUMA fault handling to use generic migration implementation
> > to migrate misplaced page. There is no functional change.
> >
> > After the refactor the flow of NUMA fault handling looks just like its
> > PTE counterpart:
> > Acquire ptl
> > Prepare for migration (elevate page refcount)
> > Release ptl
> > Isolate page from lru and elevate page refcount
> > Migrate the misplaced THP
> >
> > If migration is failed just restore the old normal PMD.
> >
> > In the old code anon_vma lock was needed to serialize THP migration
> > against THP split, but since then the THP code has been reworked a lot,
> > it seems anon_vma lock is not required anymore to avoid the race.
> >
> > The page refcount elevation when holding ptl should prevent from THP
> > split.
> >
> > Use migrate_misplaced_page() for both base page and THP NUMA hinting
> > fault and remove all the dead and duplicate code.
> >
> > Signed-off-by: Yang Shi <shy828301@gmail.com>
>
> I did not spot any big problems and FWIW, the series overall passed a
> series of tests that exercise NUMA balancing migrations so...
>
> Acked-by: Mel Gorman <mgorman@suse.de>
Thanks a lot for testing and reviewing the series.
>
> --
> Mel Gorman
> SUSE Labs
next prev parent reply other threads:[~2021-05-17 19:41 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 21:24 [v2 RFC PATCH 0/7] mm: thp: use generic THP migration for NUMA hinting fault Yang Shi
2021-04-13 21:24 ` [v2 PATCH 1/7] mm: memory: add orig_pmd to struct vm_fault Yang Shi
2021-05-17 15:09 ` Mel Gorman
2021-05-17 19:39 ` Yang Shi
2021-05-18 7:36 ` Mel Gorman
2021-05-18 17:03 ` Yang Shi
2021-04-13 21:24 ` [v2 PATCH 2/7] mm: memory: make numa_migrate_prep() non-static Yang Shi
2021-05-17 15:11 ` Mel Gorman
2021-04-13 21:24 ` [v2 PATCH 3/7] mm: thp: refactor NUMA fault handling Yang Shi
2021-04-14 2:43 ` Huang, Ying
2021-04-14 17:15 ` Yang Shi
2021-05-17 15:27 ` Mel Gorman
2021-05-17 19:41 ` Yang Shi [this message]
2021-04-13 21:24 ` [v2 PATCH 4/7] mm: migrate: account THP NUMA migration counters correctly Yang Shi
2021-05-17 15:28 ` Mel Gorman
2021-04-13 21:24 ` [v2 PATCH 5/7] mm: migrate: don't split THP for misplaced NUMA page Yang Shi
2021-05-17 15:29 ` Mel Gorman
2021-04-13 21:24 ` [v2 PATCH 6/7] mm: migrate: check mapcount for THP instead of ref count Yang Shi
2021-04-14 3:00 ` Huang, Ying
2021-04-14 15:02 ` Zi Yan
2021-04-15 6:45 ` Huang, Ying
2021-04-15 18:57 ` Zi Yan
2021-04-14 17:23 ` Yang Shi
2021-04-13 21:24 ` [v2 PATCH 7/7] mm: thp: skip make PMD PROT_NONE if THP migration is not supported Yang Shi
2021-05-17 15:30 ` Mel Gorman
2021-05-03 21:58 ` [v2 RFC PATCH 0/7] mm: thp: use generic THP migration for NUMA hinting fault Yang Shi
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