Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751288AbdGQH1z (ORCPT ); Mon, 17 Jul 2017 03:27:55 -0400 Received: from mail-pg0-f66.google.com ([74.125.83.66]:34500 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751257AbdGQH1y (ORCPT ); Mon, 17 Jul 2017 03:27:54 -0400 From: Zhaoyang Huang X-Google-Original-From: Zhaoyang Huang To: zhaoyang.huang@spreadtrum.com, Andrew Morton , Michal Hocko , Ingo Molnar , zijun_hu , Vlastimil Babka , Thomas Garnier , "Kirill A. Shutemov" , Andrey Ryabinin , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] mm/vmalloc: terminate searching since one node found Date: Mon, 17 Jul 2017 15:27:31 +0800 Message-Id: <1500276451-10492-1-git-send-email-zhaoyang.huang@spreadtrum.com> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1536 Lines: 52 From: Zhaoyang Huang 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 For current approach, the worst case is that the starting node which be found for searching the 'vmap_area_list' is close to the 'vstart', while the final available one is round to the tail(especially for the left branch). This commit have the list searching start at the first available node, which will save the time of walking the rb tree'(1)' and walking the list(2). vmap_area_root / \ tmp_next U / (1) tmp / ... / first(current approach) vmap_area_list->...->first->...->tmp->tmp_next (2) Signed-off-by: Zhaoyang Huang --- 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