From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755859Ab2BADiS (ORCPT ); Tue, 31 Jan 2012 22:38:18 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:60762 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755840Ab2BADiQ (ORCPT ); Tue, 31 Jan 2012 22:38:16 -0500 From: Frederic Weisbecker To: Andrew Morton , Tejun Heo , Li Zefan Cc: LKML , "Kirill A. Shutemov" , Frederic Weisbecker , Paul Menage , Johannes Weiner , Aditya Kali , Oleg Nesterov , Tim Hockin , Tejun Heo , Containers , Glauber Costa , Cgroups , Daniel J Walsh , "Daniel P. Berrange" , KAMEZAWA Hiroyuki , Max Kellermann , Mandeep Singh Baines Subject: [PATCH 04/10] cgroups: add res counter common ancestor searching Date: Wed, 1 Feb 2012 04:37:44 +0100 Message-Id: <1328067470-5980-5-git-send-email-fweisbec@gmail.com> X-Mailer: git-send-email 1.7.5.4 In-Reply-To: <1328067470-5980-1-git-send-email-fweisbec@gmail.com> References: <1328067470-5980-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Kirill A. Shutemov" Add a new API to find the common ancestor between two resource counters. This includes the passed resource counter themselves. Signed-off-by: Kirill A. Shutemov Signed-off-by: Frederic Weisbecker Cc: Li Zefan Cc: Paul Menage Cc: Johannes Weiner Cc: Aditya Kali Cc: Oleg Nesterov Cc: Tim Hockin Cc: Tejun Heo Cc: Containers Cc: Glauber Costa Cc: Cgroups Cc: Daniel J Walsh Cc: "Daniel P. Berrange" Cc: KAMEZAWA Hiroyuki Cc: Max Kellermann Cc: Mandeep Singh Baines Signed-off-by: Andrew Morton --- include/linux/res_counter.h | 3 +++ kernel/res_counter.c | 33 +++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+), 0 deletions(-) diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h index de4ba29..558f39b 100644 --- a/include/linux/res_counter.h +++ b/include/linux/res_counter.h @@ -147,6 +147,9 @@ static inline void res_counter_uncharge(struct res_counter *counter, res_counter_uncharge_until(counter, NULL, val); } +struct res_counter *res_counter_common_ancestor(struct res_counter *l, + struct res_counter *r); + /** * res_counter_margin - calculate chargeable space of a counter * @cnt: the counter diff --git a/kernel/res_counter.c b/kernel/res_counter.c index 40f15aa..6dc6164 100644 --- a/kernel/res_counter.c +++ b/kernel/res_counter.c @@ -91,6 +91,39 @@ void res_counter_uncharge_until(struct res_counter *counter, local_irq_restore(flags); } +/* + * Walk through r1 and r2 parents and try to find the closest common one + * between both. If none is found, it returns NULL. + */ +struct res_counter * +res_counter_common_ancestor(struct res_counter *r1, struct res_counter *r2) +{ + struct res_counter *iter; + int r1_depth = 0, r2_depth = 0; + + for (iter = r1; iter; iter = iter->parent) + r1_depth++; + + for (iter = r2; iter; iter = iter->parent) + r2_depth++; + + while (r1_depth > r2_depth) { + r1 = r1->parent; + r1_depth--; + } + + while (r2_depth > r1_depth) { + r2 = r2->parent; + r2_depth--; + } + + while (r1 != r2) { + r1 = r1->parent; + r2 = r2->parent; + } + + return r1; +} static inline unsigned long long * res_counter_member(struct res_counter *counter, int member) -- 1.7.5.4