From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Grundler Subject: Re: Another ldcw inline assembler patch Date: Sun, 29 Jun 2008 14:55:56 -0600 Message-ID: <20080629205556.GA8381@colo.lackof.org> References: <20080628220756.GA8620@hiauly1.hia.nrc.ca> <20080628233406.GI14894@parisc-linux.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: John David Anglin , linux-parisc@vger.kernel.org To: Matthew Wilcox Return-path: In-Reply-To: <20080628233406.GI14894@parisc-linux.org> List-ID: List-Id: linux-parisc.vger.kernel.org On Sat, Jun 28, 2008 at 05:34:07PM -0600, Matthew Wilcox wrote: > On Sat, Jun 28, 2008 at 06:07:57PM -0400, John David Anglin wrote: > > There are two reasons to expose the memory *a in the asm: > > > > 1) To prevent the compiler from discarding a preceeding write to *a, and > > 2) to prevent it from caching *a in a register over the asm. > > Do either of those scenarios apply, given that every usage of this is > preceded by an asm clobbering memory? > > I believe the correct thing to do is to take out the two mb()s in the > various spin_lock routines and make the __ldcw() macro itself clobber > memory. I agree. Do you want jda to submit another patch or did you want kyle to take jda's patch and apply a second one to remove the mb()'s? thanks. grant > > -- > Intel are signing my paycheques ... these opinions are still mine > "Bill, look, we understand that you're interested in selling us this > operating system, but compare it to ours. We can't possibly take such > a retrograde step." > -- > To unsubscribe from this list: send the line "unsubscribe linux-parisc" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html