From: Michal Hocko <mhocko@kernel.org>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Stephen Rothwell <sfr@canb.auug.org.au>,
linux-mm@kvack.org, linux-next@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [linux-next: Tree for Jun 1] __khugepaged_exit rwsem_down_write_failed lockup
Date: Mon, 6 Jun 2016 10:39:46 +0200 [thread overview]
Message-ID: <20160606083946.GG11895@dhcp22.suse.cz> (raw)
In-Reply-To: <20160604075114.GA21108@swordfish>
On Sat 04-06-16 16:51:14, Sergey Senozhatsky wrote:
> Hello,
>
> On (06/03/16 15:49), Michal Hocko wrote:
> > __khugepaged_exit is called during the final __mmput and it employs a
> > complex synchronization dances to make sure it doesn't race with the
> > khugepaged which might be scanning this mm at the same time. This is
> > all caused by the fact that khugepaged doesn't pin mm_users. Things
> > would simplify considerably if we simply check the mm at
> > khugepaged_scan_mm_slot and if mm_users was already 0 then we know it
> > is dead and we can unhash the mm_slot and move on to another one. This
> > will also guarantee that __khugepaged_exit cannot race with khugepaged
> > and so we can free up the slot if it is still hashed.
> >
> > Signed-off-by: Michal Hocko <mhocko@suse.com>
>
> with this patch and
> http://ozlabs.org/~akpm/mmotm/broken-out/mm-thp-make-swapin-readahead-under-down_read-of-mmap_sem-fix-2.patch
>
> I saw no problems during my tests (well, may be didn't test hard
> enough).
Thanks for the testing!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2016-06-06 8:39 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 3:11 linux-next: Tree for Jun 1 Stephen Rothwell
2016-06-02 1:48 ` [linux-next: Tree for Jun 1] __khugepaged_exit rwsem_down_write_failed lockup Sergey Senozhatsky
2016-06-02 9:21 ` Michal Hocko
2016-06-02 12:08 ` Sergey Senozhatsky
2016-06-02 12:21 ` Michal Hocko
2016-06-03 13:51 ` Andrea Arcangeli
2016-06-03 14:46 ` Michal Hocko
2016-06-03 15:10 ` Andrea Arcangeli
2016-06-07 7:34 ` Michal Hocko
2016-06-08 8:19 ` Vlastimil Babka
2016-06-03 7:15 ` Sergey Senozhatsky
2016-06-03 7:25 ` Michal Hocko
2016-06-03 8:43 ` Sergey Senozhatsky
2016-06-03 9:55 ` Michal Hocko
2016-06-03 10:05 ` Michal Hocko
2016-06-03 13:38 ` Sergey Senozhatsky
2016-06-03 13:45 ` Michal Hocko
2016-06-03 13:49 ` Michal Hocko
2016-06-04 7:51 ` Sergey Senozhatsky
2016-06-06 8:39 ` Michal Hocko [this message]
2016-06-02 13:24 ` Vlastimil Babka
2016-06-02 18:58 ` Ebru Akagunduz
2016-06-03 1:00 ` Sergey Senozhatsky
2016-06-03 1:29 ` Sergey Senozhatsky
2016-06-03 4:14 ` Sergey Senozhatsky
2016-06-03 12:28 ` [PATCH] mm, thp: fix locking inconsistency in collapse_huge_page Ebru Akagunduz
2016-06-06 13:05 ` Vlastimil Babka
2016-06-09 3:51 ` Sergey Senozhatsky
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