From: Steven Rostedt <rostedt@goodmis.org>
To: Christoph Lameter <cl@linux.com>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org,
Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>
Subject: Re: [for-next][PATCH 1/4] ring-buffer: Replace this_cpu_*() with __this_cpu_*()
Date: Mon, 30 Mar 2015 09:37:20 -0400 [thread overview]
Message-ID: <20150330093720.6bfbf82f@gandalf.local.home> (raw)
In-Reply-To: <alpine.DEB.2.11.1503300743080.2887@gentwo.org>
On Mon, 30 Mar 2015 07:44:30 -0500 (CDT)
Christoph Lameter <cl@linux.com> wrote:
> > >
> > > or more compact
> > >
> > > unsigned int val = __this_cpu_read(current_context);
> > >
> > > __this_cpu_write(current_context, val & (val - 1));
> >
> > Maybe I'll just use your compact version.
>
> Hmmm... It could even be more compact
>
> __this_cpu_and(current_context, __this_cpu_read(current_context) - 1);
Hmm, I didn't realize there was an "and" version. I'm guessing this
would bring down the instruction count even more?
/me tries it.
I just finished testing my previous version. If this does prove to be
more compact, I'll have to replace that one with this one.
-- Steve
next prev parent reply other threads:[~2015-03-30 13:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-25 13:00 [for-next][PATCH 0/4] tracing: updates for 4.1 Steven Rostedt
2015-03-25 13:00 ` [for-next][PATCH 1/4] ring-buffer: Replace this_cpu_*() with __this_cpu_*() Steven Rostedt
2015-03-27 19:41 ` Christoph Lameter
2015-03-27 20:11 ` Steven Rostedt
2015-03-30 12:44 ` Christoph Lameter
2015-03-30 13:37 ` Steven Rostedt [this message]
2015-03-30 14:32 ` Christoph Lameter
2015-03-27 21:50 ` [PATCH] ring-buffer: Remove duplicate use of '&' in recursive code Steven Rostedt
2015-03-25 13:00 ` [for-next][PATCH 2/4] tracing: %pF is only for function pointers Steven Rostedt
2015-03-25 13:00 ` [for-next][PATCH 3/4] tracing: remove ftrace:function TRACE_EVENT_FL_USE_CALL_FILTER flag Steven Rostedt
2015-03-25 13:00 ` [for-next][PATCH 4/4] trace: Dont use __weak in header files Steven Rostedt
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