[PATCH 2/8] cgroups: new resource counter inheritance API
From: Frederic Weisbecker <hidden>
Date: 2012-01-13 18:15:19
Also in:
lkml
Subsystem:
the rest · Maintainer:
Linus Torvalds
Provide an API to inherit a counter value from a parent. This can be useful to implement cgroup.clone_children on a resource counter. Still the resources of the children are limited by those of the parent, so this is only to provide a default setting behaviour when clone_children is set. Signed-off-by: Frederic Weisbecker <redacted> Cc: Paul Menage <redacted> Cc: Li Zefan <redacted> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Aditya Kali <redacted> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Kay Sievers <redacted> Cc: Tim Hockin <redacted> Cc: Tejun Heo <redacted> Acked-by: Kirill A. Shutemov <redacted> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- include/linux/res_counter.h | 2 ++ kernel/res_counter.c | 18 ++++++++++++++++++ 2 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 1b3fe05..109d118 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h@@ -84,6 +84,8 @@ int res_counter_write(struct res_counter *counter, int member, void res_counter_write_u64(struct res_counter *counter, int member, u64 val); +void res_counter_inherit(struct res_counter *counter, int member); + /* * the field descriptors. one for each member of res_counter */
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 58ae85e..016b4d4 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c@@ -201,3 +201,21 @@ int res_counter_write(struct res_counter *counter, int member, return 0; } + +/* + * Simple inheritance implementation to get the same value + * than a parent. However this doesn't enforce the child value + * to be always below the one of the parent. But the child is + * subject to its parent limitation anyway. + */ +void res_counter_inherit(struct res_counter *counter, int member) +{ + struct res_counter *parent; + unsigned long long val; + + parent = counter->parent; + if (parent) { + val = res_counter_read_u64(parent, member); + res_counter_write_u64(counter, member, val); + } +}
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1.7.5.4