From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
"David S. Miller" <davem@davemloft.net>,
Tony Luck <tony.luck@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Chris Zankel <chris@zankel.net>,
Max Filippov <jcmvbkbc@gmail.com>,
x86@kernel.org, linux-alpha@vger.kernel.org,
linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org,
Michal Hocko <mhocko@suse.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
Jason Low <jason.low2@hpe.com>
Subject: Re: [RFC 10/12] x86, rwsem: simplify __down_write
Date: Sat, 4 Jun 2016 00:34:17 +0200 [thread overview]
Message-ID: <20160603223417.GB3892@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160603161339.GC3693@twins.programming.kicks-ass.net>
On Fri, Jun 03, 2016 at 06:13:39PM +0200, Peter Zijlstra wrote:
> So I've been playing with this again because Jason's atomic_long_t
> patches made a mess of things.
>
> (similar findings for both ia64 and s390, suggesting killing all
> arch/*/include/asm/rwsem.h might actuyally be an option).
>
Blergh; so looking at more asm there's still a few tricks we cannot do.
So while overall size is down, some paths do end up more expensive. (It
typically boils down to creative use of condition flags, which is very
hard in C)
next prev parent reply other threads:[~2016-06-03 22:34 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-02 20:19 [RFC 0/12] introduce down_write_killable for rw_semaphore Michal Hocko
2016-02-02 20:19 ` [RFC 01/12] locking, rwsem: get rid of __down_write_nested Michal Hocko
2016-02-02 20:19 ` [RFC 02/12] locking, rwsem: drop explicit memory barriers Michal Hocko
2016-02-02 20:19 ` [RFC 03/12] locking, rwsem: introduce basis for down_write_killable Michal Hocko
2016-02-02 20:19 ` [RFC 04/12] alpha, rwsem: provide __down_write_killable Michal Hocko
2016-02-02 20:19 ` [RFC 05/12] ia64, " Michal Hocko
2016-02-02 20:19 ` [RFC 06/12] s390, " Michal Hocko
2016-02-02 20:19 ` [RFC 07/12] sh, " Michal Hocko
2016-02-03 11:19 ` Sergei Shtylyov
2016-02-03 12:11 ` Michal Hocko
2016-02-02 20:19 ` [RFC 08/12] sparc, " Michal Hocko
2016-02-02 20:19 ` [RFC 09/12] xtensa, " Michal Hocko
2016-02-02 20:19 ` [RFC 10/12] x86, rwsem: simplify __down_write Michal Hocko
2016-02-03 8:10 ` Ingo Molnar
2016-02-03 12:10 ` Michal Hocko
2016-06-03 16:13 ` Peter Zijlstra
2016-06-03 22:34 ` Peter Zijlstra [this message]
2016-06-09 14:40 ` David Howells
2016-06-09 17:36 ` Peter Zijlstra
2016-06-10 16:39 ` Paul E. McKenney
2016-02-02 20:19 ` [RFC 11/12] x86, rwsem: provide __down_write_killable Michal Hocko
2016-02-17 16:41 ` [RFC 11/12 v1] " Michal Hocko
2016-02-02 20:19 ` [RFC 12/12] locking, rwsem: provide down_write_killable Michal Hocko
2016-02-19 12:15 ` [RFC 0/12] introduce down_write_killable for rw_semaphore Michal Hocko
2016-03-09 12:18 ` Ingo Molnar
2016-03-09 12:56 ` Michal Hocko
2016-03-09 13:17 ` Ingo Molnar
2016-03-09 13:28 ` Michal Hocko
2016-03-09 13:43 ` Ingo Molnar
2016-03-09 14:41 ` Michal Hocko
2016-03-10 10:24 ` Ingo Molnar
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