From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederic Weisbecker Subject: [PATCH 4/8] cgroups: add res counter common ancestor searching Date: Fri, 13 Jan 2012 19:13:52 +0100 Message-ID: <1326478441-3048-9-git-send-email-fweisbec@gmail.com> References: <1326478441-3048-1-git-send-email-fweisbec@gmail.com> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:in-reply-to:references; bh=ae76N6JD4qcJGgd3Vsd0nMRFGpZheRFw/I0XW8AEbiI=; b=G0Ez4xabbGT7khQpPDQmZ9rn6B5s/UlwkprHLV615RxOD5uqxenOQcl3S79oiqhcfk xKaIRgfjwNcfyo7syclxmnSETmuY4djLcV7Nzy1q0kl8f326EuaGCNayxOteJNc8yuIZ J4N/sv3n0mKOKH3pXozk/KRPcaDGyCoAen2aU= In-Reply-To: <1326478441-3048-1-git-send-email-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: LKML Cc: "Kirill A. Shutemov" , Glauber Costa , Cgroups , Daniel J Walsh , "Daniel P. Berrange" , KAMEZAWA Hiroyuki , Max Kellermann , Mandeep Singh Baines , Frederic Weisbecker , Li Zefan , Paul Menage , Johannes Weiner , Aditya Kali , Oleg Nesterov , Kay Sievers , Tim Hockin , Tejun Heo , Andrew Morton 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: Kay Sievers Cc: Tim Hockin Cc: Tejun Heo Cc: Kirill A. Shutemov 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 8ef09a4..86d72b8 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