From: Ingo Molnar <mingo@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Waiman Long <Waiman.Long@hp.com>, Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Peter Hurley <peter@hurleysoftware.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
Alex Shi <alex.shi@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Andrea Arcangeli <aarcange@redhat.com>,
Matthew R Wilcox <matthew.r.wilcox@intel.com>,
Dave Hansen <dave.hansen@intel.com>,
Michel Lespinasse <walken@google.com>,
Andi Kleen <andi@firstfloor.org>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
"Norton, Scott J" <scott.norton@hp.com>
Subject: Re: [PATCH] anon_vmas: Convert the rwsem to an rwlock_t
Date: Sat, 28 Sep 2013 21:46:49 +0200 [thread overview]
Message-ID: <20130928194649.GB8640@gmail.com> (raw)
In-Reply-To: <CA+55aFyMXxH-PGewqxse=VJzMdHWkyN4iKMh-VgQ1X2yJFnAgw@mail.gmail.com>
* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Sat, Sep 28, 2013 at 12:37 PM, Ingo Molnar <mingo@kernel.org> wrote:
> >
> > - down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_sem);
> > + down_write_nest_lock(&anon_vma->root->rwlock, &mm->mmap_sem);
>
> That's just completely bogus, and cannot work.
Told you it's totally untested :-) Found that build failure a few minutes
ago (the place escaped my search pattern), I'm trying the fix below.
Ingo
diff --git a/mm/mmap.c b/mm/mmap.c
index 25ce233..7ee85bf 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2955,7 +2955,7 @@ static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma)
* The LSB of head.next can't change from under us
* because we hold the mm_all_locks_mutex.
*/
- down_write_nest_lock(&anon_vma->root->rwlock, &mm->mmap_sem);
+ write_lock(&anon_vma->root->rwlock);
/*
* We can safely modify head.next after taking the
* anon_vma->root->rwlock. If some other vma in this mm shares
next prev parent reply other threads:[~2013-09-28 19:46 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 19:00 [PATCH] rwsem: reduce spinlock contention in wakeup code path Waiman Long
2013-09-27 19:28 ` Linus Torvalds
2013-09-27 19:39 ` Davidlohr Bueso
2013-09-27 21:49 ` Tim Chen
2013-09-28 6:45 ` Ingo Molnar
2013-09-28 7:41 ` Ingo Molnar
2013-09-28 18:55 ` Linus Torvalds
2013-09-28 19:13 ` Andi Kleen
2013-09-28 19:22 ` Linus Torvalds
2013-09-28 19:21 ` Ingo Molnar
2013-09-28 19:33 ` Linus Torvalds
2013-09-28 19:39 ` Ingo Molnar
2013-09-30 10:44 ` Peter Zijlstra
2013-09-30 16:13 ` Linus Torvalds
2013-09-30 16:41 ` Peter Zijlstra
2013-10-01 7:28 ` Ingo Molnar
2013-10-01 8:09 ` Peter Zijlstra
2013-10-01 8:25 ` Ingo Molnar
2013-09-30 15:58 ` Waiman Long
2013-10-01 7:33 ` Ingo Molnar
2013-10-01 20:03 ` Waiman Long
2013-09-28 19:37 ` [PATCH] anon_vmas: Convert the rwsem to an rwlock_t Ingo Molnar
2013-09-28 19:43 ` Linus Torvalds
2013-09-28 19:46 ` Ingo Molnar [this message]
2013-09-28 19:52 ` [PATCH, v2] " Ingo Molnar
2013-09-30 11:00 ` Peter Zijlstra
2013-09-30 11:44 ` Peter Zijlstra
2013-09-30 17:03 ` Andrew Morton
2013-09-30 17:25 ` Linus Torvalds
2013-09-30 17:10 ` Tim Chen
2013-09-30 18:14 ` Peter Zijlstra
2013-09-30 19:23 ` Tim Chen
2013-09-30 19:35 ` Waiman Long
2013-09-30 19:47 ` Tim Chen
2013-09-30 22:03 ` Tim Chen
2013-10-01 2:41 ` Waiman Long
2013-09-30 8:52 ` [PATCH] " Andrea Arcangeli
2013-09-30 14:40 ` Jerome Glisse
2013-09-30 16:26 ` Linus Torvalds
2013-09-30 19:16 ` Andrea Arcangeli
2013-09-30 18:21 ` Andi Kleen
2013-09-30 19:04 ` Jerome Glisse
2013-09-29 23:06 ` [PATCH] rwsem: reduce spinlock contention in wakeup code path Davidlohr Bueso
2013-09-29 23:26 ` Linus Torvalds
2013-09-30 0:40 ` Davidlohr Bueso
2013-09-30 0:51 ` Linus Torvalds
2013-09-30 6:57 ` Ingo Molnar
2013-09-30 1:11 ` Michel Lespinasse
2013-09-30 7:05 ` Ingo Molnar
2013-09-30 16:03 ` Waiman Long
2013-09-30 10:46 ` Peter Zijlstra
2013-10-01 7:48 ` Ingo Molnar
2013-10-01 8:10 ` Peter Zijlstra
2013-09-27 19:32 ` Peter Hurley
2013-09-28 0:46 ` Waiman Long
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