linux-kernel - Re: [RFC PATCH] sys_membarrier(): system/process-wide memory barrier (x86) (v12)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 17 Mar 2015 09:35:55 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Peter Zijlstra <peterz@...radead.org>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	linux-kernel@...r.kernel.org,
	KOSAKI Motohiro <kosaki.motohiro@...fujitsu.com>,
	Nicholas Miell <nmiell@...cast.net>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Ingo Molnar <mingo@...hat.com>,
	Alan Cox <gnomes@...rguk.ukuu.org.uk>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Stephen Hemminger <stephen@...workplumber.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Josh Triplett <josh@...htriplett.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	David Howells <dhowells@...hat.com>,
	Christoph Lameter <cl@...ux.com>
Subject: Re: [RFC PATCH] sys_membarrier(): system/process-wide memory barrier
 (x86) (v12)

On Tue, Mar 17, 2015 at 10:10:09AM -0400, Steven Rostedt wrote:
> On Tue, 17 Mar 2015 04:44:11 -0700
> "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com> wrote:
> 
> > On Tue, Mar 17, 2015 at 07:40:56AM +0100, Peter Zijlstra wrote:
> > > On Mon, Mar 16, 2015 at 10:26:11PM -0400, Steven Rostedt wrote:
> > > > As I recently found out that this_cpu_read/write() is not that nice on
> > > > all architectures,
> > > 
> > > In fact, they only really work well on x86. Aargh64 seems to have a semi
> > > usable version, but mostly its quite horrible indeed.
> > 
> > Yeah, if you are in a preempt-disabled region, __this_cpu_read() and
> > __this_cpu_write() generate much better code on most platforms.
> 
> I was just having this discussion with Christoph. I originally switched
> to using this_cpu_ptr(), but I'll try __this_cpu* instead. I think
> Christoph recommended that too.

Sounds good to me!  ;-)

							Thanx, Paul

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/