From: Peter Zijlstra <peterz@infradead.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
Andrew Morton <akpm@linux-foundation.org>,
Russell King <linux@arm.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
linux-kernel@vger.kernel.org,
linux-api <linux-api@vger.kernel.org>,
Paul Turner <pjt@google.com>, Andrew Hunter <ahh@google.com>,
Andi Kleen <andi@firstfloor.org>,
Dave Watson <davejwatson@fb.com>, Chris Lameter <cl@linux.com>,
Ben Maurer <bmaurer@fb.com>, rostedt <rostedt@goodmis.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Josh Triplett <josh@joshtriplett.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Michael Kerrisk <mtk.manpages@gmail.com>,
Boqun Feng <boqun.feng@gmail.com>
Subject: Re: [RFC PATCH v7 1/7] Restartable sequences system call
Date: Wed, 3 Aug 2016 14:27:17 +0200 [thread overview]
Message-ID: <20160803122717.GL6862@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1806206514.82247.1469502139408.JavaMail.zimbra@efficios.com>
On Tue, Jul 26, 2016 at 03:02:19AM +0000, Mathieu Desnoyers wrote:
> We really care about preemption here. Every migration implies a
> preemption from a user-space perspective. If we would only care
> about keeping the CPU id up-to-date, hooking into migration would be
> enough. But since we want atomicity guarantees for restartable
> sequences, we need to hook into preemption.
> It allows user-space to perform update operations on per-cpu data without
> requiring heavy-weight atomic operations.
Well, a CMPXCHG without LOCK prefix isn't all that expensive on x86.
It is however on PPC and possibly other architectures, so in name of
simplicity supporting only the one variant makes sense.
next prev parent reply other threads:[~2016-08-03 12:28 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-21 21:14 [RFC PATCH v7 0/7] Restartable sequences system call Mathieu Desnoyers
2016-07-21 21:14 ` [RFC PATCH v7 1/7] " Mathieu Desnoyers
2016-07-25 23:02 ` Andy Lutomirski
2016-07-26 3:02 ` Mathieu Desnoyers
2016-08-03 12:27 ` Peter Zijlstra [this message]
2016-08-03 16:37 ` Andy Lutomirski
2016-08-03 18:31 ` Christoph Lameter
2016-08-04 5:01 ` Andy Lutomirski
2016-08-04 4:27 ` Boqun Feng
2016-08-04 5:03 ` Andy Lutomirski
2016-08-09 16:13 ` Boqun Feng
2016-08-10 8:01 ` Andy Lutomirski
2016-08-10 17:40 ` Mathieu Desnoyers
2016-08-10 17:33 ` Mathieu Desnoyers
2016-08-11 4:54 ` Boqun Feng
2016-08-10 8:13 ` Andy Lutomirski
2016-08-03 18:29 ` Christoph Lameter
2016-08-10 16:47 ` Mathieu Desnoyers
2016-08-10 16:59 ` Christoph Lameter
2016-07-27 15:03 ` Boqun Feng
2016-07-27 15:05 ` [RFC 1/4] rseq/param_test: Convert test_data_entry::count to intptr_t Boqun Feng
2016-07-27 15:05 ` [RFC 2/4] Restartable sequences: powerpc architecture support Boqun Feng
2016-07-28 3:13 ` Mathieu Desnoyers
2016-07-27 15:05 ` [RFC 3/4] Restartable sequences: Wire up powerpc system call Boqun Feng
2016-07-28 3:13 ` Mathieu Desnoyers
2016-07-27 15:05 ` [RFC 4/4] Restartable sequences: Add self-tests for PPC Boqun Feng
2016-07-28 2:59 ` Mathieu Desnoyers
2016-07-28 4:43 ` Boqun Feng
2016-07-28 7:37 ` [RFC v2] " Boqun Feng
2016-07-28 14:04 ` Mathieu Desnoyers
2016-07-28 13:42 ` [RFC 4/4] " Mathieu Desnoyers
2016-07-28 3:07 ` [RFC 1/4] rseq/param_test: Convert test_data_entry::count to intptr_t Mathieu Desnoyers
2016-07-28 3:10 ` [RFC PATCH v7 1/7] Restartable sequences system call Mathieu Desnoyers
2016-08-03 13:19 ` Peter Zijlstra
2016-08-03 14:53 ` Paul E. McKenney
2016-08-03 15:45 ` Boqun Feng
2016-08-07 15:36 ` Mathieu Desnoyers
2016-08-07 23:35 ` Boqun Feng
2016-08-09 13:22 ` Mathieu Desnoyers
2016-08-09 20:06 ` Mathieu Desnoyers
2016-08-09 21:33 ` Peter Zijlstra
2016-08-09 22:41 ` Mathieu Desnoyers
2016-08-10 7:50 ` Peter Zijlstra
2016-08-10 13:26 ` Mathieu Desnoyers
2016-08-10 13:33 ` Peter Zijlstra
2016-08-10 14:04 ` Mathieu Desnoyers
2016-08-10 8:10 ` Andy Lutomirski
2016-08-10 19:04 ` Mathieu Desnoyers
2016-08-10 19:16 ` Andy Lutomirski
2016-08-10 20:06 ` Mathieu Desnoyers
2016-08-10 20:09 ` Andy Lutomirski
2016-08-10 21:01 ` Mathieu Desnoyers
2016-08-11 7:23 ` Andy Lutomirski
2016-08-10 8:43 ` Peter Zijlstra
2016-08-10 13:57 ` Mathieu Desnoyers
2016-08-10 14:28 ` Peter Zijlstra
2016-08-10 14:44 ` Mathieu Desnoyers
2016-08-10 13:29 ` Peter Zijlstra
2016-07-21 21:14 ` [RFC PATCH v7 2/7] tracing: instrument restartable sequences Mathieu Desnoyers
2016-07-21 21:14 ` [RFC PATCH v7 3/7] Restartable sequences: ARM 32 architecture support Mathieu Desnoyers
2016-07-21 21:14 ` [RFC PATCH v7 4/7] Restartable sequences: wire up ARM 32 system call Mathieu Desnoyers
2016-07-21 21:14 ` [RFC PATCH v7 5/7] Restartable sequences: x86 32/64 architecture support Mathieu Desnoyers
2016-07-21 21:14 ` [RFC PATCH v7 6/7] Restartable sequences: wire up x86 32/64 system call Mathieu Desnoyers
2016-07-21 21:14 ` [RFC PATCH v7 7/7] Restartable sequences: self-tests Mathieu Desnoyers
[not found] ` <CO1PR15MB09822FC140F84DCEEF2004CDDD0B0@CO1PR15MB0982.namprd15.prod.outlook.com>
2016-07-24 3:09 ` Mathieu Desnoyers
2016-07-24 18:01 ` Dave Watson
2016-07-25 16:43 ` Mathieu Desnoyers
2016-08-11 23:26 ` Mathieu Desnoyers
2016-08-12 1:28 ` Boqun Feng
2016-08-12 3:10 ` Mathieu Desnoyers
2016-08-12 3:13 ` Mathieu Desnoyers
2016-08-12 5:30 ` Boqun Feng
2016-08-12 16:35 ` Boqun Feng
2016-08-12 18:11 ` Mathieu Desnoyers
2016-08-13 1:28 ` Boqun Feng
2016-08-14 15:02 ` Mathieu Desnoyers
2016-08-15 0:56 ` Boqun Feng
2016-08-15 18:06 ` Mathieu Desnoyers
2016-08-12 19:36 ` Mathieu Desnoyers
2016-08-12 20:05 ` Dave Watson
2016-08-14 17:09 ` Mathieu Desnoyers
2016-07-25 18:12 ` Mathieu Desnoyers
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