[PATCH 04/10] cgroups: add res counter common ancestor searching
From: Frederic Weisbecker <hidden>
Date: 2012-02-01 03:38:18
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: "Kirill A. Shutemov" <redacted> 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 <redacted> Signed-off-by: Frederic Weisbecker <redacted> Cc: Li Zefan <redacted> Cc: Paul Menage <redacted> Cc: Johannes Weiner <redacted> Cc: Aditya Kali <redacted> Cc: Oleg Nesterov <redacted> Cc: Tim Hockin <redacted> Cc: Tejun Heo <redacted> Cc: Containers <redacted> Cc: Glauber Costa <redacted> Cc: Cgroups <redacted> Cc: Daniel J Walsh <redacted> Cc: "Daniel P. Berrange" <redacted> Cc: KAMEZAWA Hiroyuki <redacted> Cc: Max Kellermann <redacted> Cc: Mandeep Singh Baines <redacted> Signed-off-by: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org> --- 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)
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1.7.5.4