Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751482Ab3HAANI (ORCPT ); Wed, 31 Jul 2013 20:13:08 -0400 Received: from muin.pair.com ([209.68.1.55]:64929 "EHLO muin.pair.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750845Ab3HAANG (ORCPT ); Wed, 31 Jul 2013 20:13:06 -0400 Message-ID: <51F9A80E.5010307@tabi.org> Date: Wed, 31 Jul 2013 19:13:02 -0500 From: Timur Tabi User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130623 Thunderbird/17.0.7 MIME-Version: 1.0 To: Stephen Boyd CC: Arpit Goel , linux@arm.linux.org.uk, takata@linux-m32r.org, philb@gnu.org, Geert Uytterhoeven , schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, linux390@de.ibm.com, David Miller , Rob Herring , Arnd Bergmann , Stephen Warren , john.stultz@linaro.org, jesper.nilsson@axis.com, gregkh@linuxfoundation.org, sam@ravnborg.org, "linux-arm-kernel@lists.infradead.org" , lkml , linux-m32r@ml.linux-m32r.org, linux-m32r-ja@ml.linux-m32r.org, linux-m68k@vger.kernel.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, mattw@codeaurora.org Subject: Re: [PATCH 2/2] Convert PowerPC macro spin_event_timeout() to architecture independent macro References: <1375187900-17582-1-git-send-email-B44344@freescale.com> <1375187900-17582-3-git-send-email-B44344@freescale.com> <20130731071630.GI8868@codeaurora.org> <51F9A5FE.8030608@codeaurora.org> In-Reply-To: <51F9A5FE.8030608@codeaurora.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 836 Lines: 20 On 07/31/2013 07:04 PM, Stephen Boyd wrote: > If it yields why are we using udelay? Why not usleep_range()? It would > be useful to have a variant that worked in interrupt context and it > looked like that was almost possible. I've never heard of usleep_range() before, so I don't know if it applies. Apparently, udelay() includes its own call to cpu_relax(). Is it possible that cpu_relax() is a "lightweight" yield, compared to sleeping? FYI, you might want to look at the code reviews for spin_event_timeout() on the linuxppc-dev mailing list, back in March 2009. -- -- Timur Tabi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/