From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Jones Subject: Re: Word-at-a-time dcache name accesses (was Re: .. anybody know of any filesystems that depend on the exact VFS 'namehash' implementation?) Date: Tue, 27 Mar 2012 01:02:38 -0400 Message-ID: <20120327050238.GA19496@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Linus Torvalds , Jason Garrett-Glaser , Andi Kleen , "H. Peter Anvin" , Linux Kernel Mailing List , linux-fsdevel , Al Viro To: Brian Gerst Return-path: Received: from mx1.redhat.com ([209.132.183.28]:7963 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753044Ab2C0FCu (ORCPT ); Tue, 27 Mar 2012 01:02:50 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tue, Mar 27, 2012 at 12:42:19AM -0400, Brian Gerst wrote: > > I did only very limited profiling of the 32-bit case, but it's really > > just four cheap ALU instructions there and didn't really show up at > > all in the limited profiles I did. And at least I checked that the > > code worked. I have to say that the advantage of "vectorizing" this > > code is obviously much less if you can only do 4-byte "vectors", so I > > didn't actually time whether the patch *improves* anything on x86-32. > > > > This patch is causing my system (x86-64, Fedora 16) to fail to boot > when DEBUG_PAGEALLOC=n. No oops, but these error messages were in the > log for the bad kernel: I saw this too, it was fixed by f132c5be05e407a99cf582347a2ae0120acd3ad7 for me. Does your kernel have that commit ? Dave