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authorBalbir Singh <balbir@linux.vnet.ibm.com>2009-09-23 15:56:36 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-09-24 07:20:59 -0700
commit296c81d89f4f14269f7346f81442910158c0a83a (patch)
treecf0e1facd1fed8282c1885bc4126e7bca1928712 /mm/memcontrol.c
parenta6df63615b943dbef22df04c19f4506330fe835e (diff)
downloadlwn-296c81d89f4f14269f7346f81442910158c0a83a.tar.gz
lwn-296c81d89f4f14269f7346f81442910158c0a83a.zip
memory controller: soft limit interface
Add an interface to allow get/set of soft limits. Soft limits for memory plus swap controller (memsw) is currently not supported. Resource counters have been enhanced to support soft limits and new type RES_SOFT_LIMIT has been added. Unlike hard limits, soft limits can be directly set and do not need any reclaim or checks before setting them to a newer value. Kamezawa-San raised a question as to whether soft limit should belong to res_counter. Since all resources understand the basic concepts of hard and soft limits, it is justified to add soft limits here. Soft limits are a generic resource usage feature, even file system quotas support soft limits. Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c20
1 files changed, 20 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index eb9571815f0c..4ad3e6be045d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2123,6 +2123,20 @@ static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
else
ret = mem_cgroup_resize_memsw_limit(memcg, val);
break;
+ case RES_SOFT_LIMIT:
+ ret = res_counter_memparse_write_strategy(buffer, &val);
+ if (ret)
+ break;
+ /*
+ * For memsw, soft limits are hard to implement in terms
+ * of semantics, for now, we support soft limits for
+ * control without swap
+ */
+ if (type == _MEM)
+ ret = res_counter_set_soft_limit(&memcg->res, val);
+ else
+ ret = -EINVAL;
+ break;
default:
ret = -EINVAL; /* should be BUG() ? */
break;
@@ -2376,6 +2390,12 @@ static struct cftype mem_cgroup_files[] = {
.read_u64 = mem_cgroup_read,
},
{
+ .name = "soft_limit_in_bytes",
+ .private = MEMFILE_PRIVATE(_MEM, RES_SOFT_LIMIT),
+ .write_string = mem_cgroup_write,
+ .read_u64 = mem_cgroup_read,
+ },
+ {
.name = "failcnt",
.private = MEMFILE_PRIVATE(_MEM, RES_FAILCNT),
.trigger = mem_cgroup_reset,