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>
This commit is contained in:
Balbir Singh
2009-09-23 15:56:36 -07:00
committed by Linus Torvalds
parent a6df63615b
commit 296c81d89f
3 changed files with 81 additions and 0 deletions

View File

@@ -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;
@@ -2375,6 +2389,12 @@ static struct cftype mem_cgroup_files[] = {
.write_string = mem_cgroup_write,
.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),