From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx164.postini.com [74.125.245.164]) by kanga.kvack.org (Postfix) with SMTP id 2FBFE6B0068 for ; Tue, 26 Jun 2012 09:46:04 -0400 (EDT) Message-ID: <1340718349.21991.81.camel@twins> Subject: Re: [PATCH -mm v2 01/11] mm: track free size between VMAs in VMA rbtree From: Peter Zijlstra Date: Tue, 26 Jun 2012 15:45:49 +0200 In-Reply-To: <4FE9B3B4.1050305@redhat.com> References: <1340315835-28571-1-git-send-email-riel@surriel.com> <1340315835-28571-2-git-send-email-riel@surriel.com> <1340359115.18025.57.camel@twins> <4FE47D0E.3000804@redhat.com> <1340374439.18025.75.camel@twins> <4FE48054.5090407@redhat.com> <1340375872.18025.77.camel@twins> <4FE4922D.8070501@surriel.com> <1340652578.21991.18.camel@twins> <4FE8DD80.9040108@redhat.com> <1340699507.21991.32.camel@twins> <4FE9B3B4.1050305@redhat.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org List-ID: To: Rik van Riel Cc: Rik van Riel , linux-mm@kvack.org, akpm@linux-foundation.org, aarcange@redhat.com, minchan@gmail.com, kosaki.motohiro@gmail.com, andi@firstfloor.org, hannes@cmpxchg.org, mel@csn.ul.ie, linux-kernel@vger.kernel.org, danielfsantos@att.net On Tue, 2012-06-26 at 09:05 -0400, Rik van Riel wrote: > On 06/26/2012 04:31 AM, Peter Zijlstra wrote: >=20 > > If you look at your patch 1, __vma_unlink has an adjust_free_gap() righ= t > > next to the rb_augment_erase(), vma_adjust() has 3 adjust_free_gap() > > calls right next to each other. > > > > All these will do an entire path walk back to the root. I would think w= e > > could save quite a bit of updating by not having them all walk back to > > the root. No point in re-computing the top levels if you know the next > > update will change them again anyway. >=20 > The problem is, unless we look at the augmented data at > rotate time, we do not know when it is safe to stop > iterating up the tree. argh,.. you're using adjust_vma_gap() for insertions instead of rb_augment_insert(). I was going on the premise that you're doing updates for augmented data without modifying the tree structure and that doing insert/delete will keep the stuff up-to-date. So now I'm not sure why you do if (insert) adjust_free_gap(insert), since __insert_vm_struct(mm, insert) -> __vma_link() -> __vma_link_rb() already does an augment update. -- 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