From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <waiman.long@hpe.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Jason Low <jason.low2@hpe.com>,
Ding Tianhong <dingtianhong@huawei.com>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <Will.Deacon@arm.com>, Ingo Molnar <mingo@redhat.com>,
Imre Deak <imre.deak@intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Davidlohr Bueso <dave@stgolabs.net>,
Tim Chen <tim.c.chen@linux.intel.com>,
Terry Rudd <terry.rudd@hpe.com>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Jason Low <jason.low2@hp.com>,
Chris Wilson <chris@chris-wilson.co.uk>,
Daniel Vetter <daniel.vetter@ffwll.ch>
Subject: Re: [PATCH -v4 8/8] locking/mutex: Enable optimistic spinning of woken waiter
Date: Tue, 18 Oct 2016 14:19:41 +0200 [thread overview]
Message-ID: <20161018121941.GU3117@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <58055CF8.2060806@hpe.com>
On Mon, Oct 17, 2016 at 07:21:28PM -0400, Waiman Long wrote:
> On 10/07/2016 10:52 AM, Peter Zijlstra wrote:
> >@@ -600,7 +630,7 @@ __mutex_lock_common(struct mutex *lock,
> > mutex_acquire_nest(&lock->dep_map, subclass, 0, nest_lock, ip);
> >
> > if (__mutex_trylock(lock, false) ||
> >- mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx)) {
> >+ mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, false)) {
> > /* got the lock, yay! */
> > lock_acquired(&lock->dep_map, ip);
> > if (use_ww_ctx)
> >@@ -669,7 +699,8 @@ __mutex_lock_common(struct mutex *lock,
> > * state back to RUNNING and fall through the next schedule(),
> > * or we must see its unlock and acquire.
> > */
> >- if (__mutex_trylock(lock, first))
> >+ if ((first&& mutex_optimistic_spin(lock, ww_ctx, use_ww_ctx, true)) ||
> >+ __mutex_trylock(lock, first))
>
> Do we need a __mutex_trylock() here? mutex_optimistic_spin() will do the
> trylock and we have one at the top of the loop.
Yes, mutex_optimistic_spin() can be a no-op.
next prev parent reply other threads:[~2016-10-18 12:20 UTC|newest]
Thread overview: 59+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-07 14:52 [PATCH -v4 0/8] locking/mutex: Rewrite basic mutex Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 1/8] locking/drm: Kill mutex trickery Peter Zijlstra
2016-10-07 15:43 ` Peter Zijlstra
2016-10-07 15:58 ` Linus Torvalds
2016-10-07 16:13 ` Peter Zijlstra
2016-10-07 21:58 ` Waiman Long
2016-10-08 11:58 ` Thomas Gleixner
2016-10-08 14:01 ` Peter Zijlstra
2016-10-08 14:11 ` Thomas Gleixner
2016-10-08 16:42 ` Peter Zijlstra
2016-11-09 10:38 ` Peter Zijlstra
2016-10-18 12:48 ` Peter Zijlstra
2016-10-18 12:57 ` Peter Zijlstra
2016-11-11 11:22 ` Daniel Vetter
2016-11-11 11:38 ` Peter Zijlstra
2016-11-12 10:58 ` Ingo Molnar
2016-11-14 14:04 ` Peter Zijlstra
2016-11-14 14:27 ` Ingo Molnar
2016-10-18 12:57 ` Chris Wilson
2016-10-07 14:52 ` [PATCH -v4 2/8] locking/mutex: Rework mutex::owner Peter Zijlstra
2016-10-12 17:59 ` Davidlohr Bueso
2016-10-12 19:52 ` Jason Low
2016-10-13 15:18 ` Will Deacon
2016-10-07 14:52 ` [PATCH -v4 3/8] locking/mutex: Kill arch specific code Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 4/8] locking/mutex: Allow MUTEX_SPIN_ON_OWNER when DEBUG_MUTEXES Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 5/8] locking/mutex: Add lock handoff to avoid starvation Peter Zijlstra
2016-10-13 15:14 ` Will Deacon
2016-10-17 9:22 ` Peter Zijlstra
2016-10-17 18:45 ` Waiman Long
2016-10-17 19:07 ` Waiman Long
2016-10-18 13:02 ` Peter Zijlstra
2016-10-18 12:36 ` Peter Zijlstra
2016-12-27 13:55 ` Chris Wilson
2017-01-09 11:52 ` [PATCH] locking/mutex: Clear mutex-handoff flag on interrupt Chris Wilson
2017-01-11 16:43 ` Peter Zijlstra
2017-01-11 16:57 ` Chris Wilson
2017-01-12 20:58 ` Chris Wilson
2016-10-07 14:52 ` [PATCH -v4 6/8] locking/mutex: Restructure wait loop Peter Zijlstra
2016-10-13 15:17 ` Will Deacon
2016-10-17 10:44 ` Peter Zijlstra
2016-10-17 13:24 ` Peter Zijlstra
2016-10-17 13:45 ` Boqun Feng
2016-10-17 15:49 ` Peter Zijlstra
2016-10-19 17:34 ` Peter Zijlstra
2016-10-24 1:57 ` ciao set_task_state() (was Re: [PATCH -v4 6/8] locking/mutex: Restructure wait loop) Davidlohr Bueso
2016-10-24 13:26 ` Kent Overstreet
2016-10-24 14:27 ` Kent Overstreet
2016-10-25 16:55 ` Eric Wheeler
2016-10-25 17:45 ` Kent Overstreet
2016-10-17 23:16 ` [PATCH -v4 6/8] locking/mutex: Restructure wait loop Waiman Long
2016-10-18 13:14 ` Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 7/8] locking/mutex: Simplify some ww_mutex code in __mutex_lock_common() Peter Zijlstra
2016-10-07 14:52 ` [PATCH -v4 8/8] locking/mutex: Enable optimistic spinning of woken waiter Peter Zijlstra
2016-10-13 15:28 ` Will Deacon
2016-10-17 9:32 ` Peter Zijlstra
2016-10-17 23:21 ` Waiman Long
2016-10-18 12:19 ` Peter Zijlstra [this message]
2016-10-07 15:20 ` [PATCH -v4 0/8] locking/mutex: Rewrite basic mutex Linus Torvalds
2016-10-11 18:42 ` Jason Low
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20161018121941.GU3117@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=Will.Deacon@arm.com \
--cc=chris@chris-wilson.co.uk \
--cc=daniel.vetter@ffwll.ch \
--cc=dave@stgolabs.net \
--cc=dingtianhong@huawei.com \
--cc=imre.deak@intel.com \
--cc=jason.low2@hp.com \
--cc=jason.low2@hpe.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=paulmck@us.ibm.com \
--cc=terry.rudd@hpe.com \
--cc=tglx@linutronix.de \
--cc=tim.c.chen@linux.intel.com \
--cc=torvalds@linux-foundation.org \
--cc=waiman.long@hpe.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).