Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751315AbdGQHAb (ORCPT ); Mon, 17 Jul 2017 03:00:31 -0400 Received: from mx2.suse.de ([195.135.220.15]:44376 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751257AbdGQHAa (ORCPT ); Mon, 17 Jul 2017 03:00:30 -0400 Date: Mon, 17 Jul 2017 09:00:25 +0200 From: Michal Hocko To: Zhaoyang Huang Cc: zhaoyang.huang@spreadtrum.com, Andrew Morton , Ingo Molnar , zijun_hu , Vlastimil Babka , Thomas Garnier , "Kirill A. Shutemov" , Andrey Ryabinin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmalloc: terminate searching since one node found Message-ID: <20170717070024.GC7397@dhcp22.suse.cz> References: <1500190107-2192-1-git-send-email-zhaoyang.huang@spreadtrum.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1500190107-2192-1-git-send-email-zhaoyang.huang@spreadtrum.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1305 Lines: 45 On Sun 16-07-17 15:28:27, Zhaoyang Huang wrote: > It is no need to find the very beginning of the area within > alloc_vmap_area, which can be done by judging each node during the process Please describe _why_ the patch is needed. I suspect this is an optimization but for which workloads it matters and how much. > Signed-off-by: Zhaoyang Huang > Signed-off-by: Zhaoyang Huang no need to to make your s-o-b twice. Just use the same one as the From (author of the patch). > --- > mm/vmalloc.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 34a1c3e..f833e07 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -459,9 +459,16 @@ static struct vmap_area *alloc_vmap_area(unsigned long size, > > while (n) { > struct vmap_area *tmp; > + struct vmap_area *tmp_next; > tmp = rb_entry(n, struct vmap_area, rb_node); > + tmp_next = list_next_entry(tmp, list); > if (tmp->va_end >= addr) { > first = tmp; > + if (ALIGN(tmp->va_end, align) + size > + < tmp_next->va_start) { > + addr = ALIGN(tmp->va_end, align); > + goto found; > + } > if (tmp->va_start <= addr) > break; > n = n->rb_left; > -- > 1.9.1 > -- Michal Hocko SUSE Labs