From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id A76956B00DA for ; Mon, 23 Mar 2009 08:29:14 -0400 (EDT) Date: Mon, 23 Mar 2009 10:35:03 -0300 From: "Luiz Fernando N. Capitulino" Subject: Re: PATCH: Introduce struct vma_link_info Message-ID: <20090323103503.1a09d6d4@mandriva.com.br> In-Reply-To: <1237581389.4667.130.camel@laptop> References: <20090320103438.08e67358@doriath.conectiva> <1237581389.4667.130.camel@laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Peter Zijlstra Cc: akpm@linux-foundation.org, riel@redhat.com, mingo@elte.hu, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ehabkost@redhat.com List-ID: Em Fri, 20 Mar 2009 21:36:29 +0100 Peter Zijlstra escreveu: | On Fri, 2009-03-20 at 10:34 -0300, Luiz Fernando N. Capitulino wrote: | > Andrew, | > | > Currently find_vma_prepare() and low-level VMA functions (eg. __vma_link()) | > require callers to provide three parameters to return/pass "link" information | > (pprev, rb_link and rb_parent): | > | > static struct vm_area_struct * | > find_vma_prepare(struct mm_struct *mm, unsigned long addr, | > struct vm_area_struct **pprev, struct rb_node ***rb_link, | > struct rb_node ** rb_parent); | > | > With this patch callers can pass a struct vma_link_info instead: | > | > static struct vm_area_struct * | > find_vma_prepare(struct mm_struct *mm, unsigned long addr, | > struct vma_link_info *link_info); | > | > The code gets simpler and it should be better because less variables | > are pushed into the stack/registers. As shown by the following | > kernel build test: | > | > kernel real user sys | > | > 2.6.29-rc8-vanilla 1136.64 1033.38 82.88 | > 2.6.29-rc8-linfo 1135.07 1032.44 82.92 | > | > I have also ran hackbench, but I can't understand why its result | > indicates a regression: | > | > kernel Avarage of three runs (25 processes groups) | > | > 2.6.29.rc8-vanilla 2.03 | > 2.6.29.rc8-linfo 2.12 | > | > Rik has said to me that this could be inside error margin. So, I'm | > submitting the patch for inclusion. | > | > Signed-off-by: Luiz Fernando N. Capitulino | | I'd rather we look into using the threaded RB-tree to get rid of all | this prev crap. Okay, it makes sense. Also, Eduardo has a point for the hackbench's regression: the patch is probably dropping some of gcc's optimizations on the variables that got packed into the struct (although I haven't checked the assembly yet). So, better to forget this one. Are there patches for the threaded tree available already? -- Luiz Fernando N. Capitulino -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org