From: Peter Zijlstra <peterz@infradead.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>, 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>,
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] rwsem: reduce spinlock contention in wakeup code path
Date: Mon, 30 Sep 2013 18:41:41 +0200 [thread overview]
Message-ID: <20130930164141.GH3081@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <CA+55aFwTCCXaD4S4OPGmwf=fhOwWdxr8NU9uFvdf_nRx0Nk0_w@mail.gmail.com>
On Mon, Sep 30, 2013 at 09:13:52AM -0700, Linus Torvalds wrote:
> So unlike a lot of other "let's try to make our locking fancy" that I
> dislike because it tends to hide the fundamental problem of
> contention, the rwlock patches make me go "those actually _fix_ a
> fundamental problem".
So here I'm slightly disagreeing; fixing a fundamental problem would be
coming up a better anon_vma management that doesn't create such immense
chains.
Its still the same lock, spinlock or not.
And regardless of if we keep anon_vma lock a rwsem or not; I think we
should merge those rwsem patches as they do improve the lock
implementation and the hard work has already been done.
However the biggest ugly by far here is that mm_take_all_locks() thing;
couldn't we implement that by basically freezing all tasks referencing
that mm?
next prev parent reply other threads:[~2013-09-30 16:42 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-27 19:00 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 [this message]
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
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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