Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 4/8] cgroups: add res counter common ancestor searching | Date | Fri, 13 Jan 2012 19:13:53 +0100 |
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From: "Kirill A. Shutemov" <kirill@shutemov.name>
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 <kirill@shutemov.name> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <paul@paulmenage.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <adityakali@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Tim Hockin <thockin@hockin.org> Cc: Tejun Heo <htejun@gmail.com> Cc: Kirill A. Shutemov <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.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 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
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