Shrinking memory usage at limit change.
This is an enhancement (in TODO list).
based on res_counter-limit-change-ebusy.patch
Changelog: v2 -> v3
- supported interrupt by signal. (A user can stop limit change by Ctrl-C.)
Changelog: v1 -> v2
- adjusted to be based on write_string() patch set
- removed backword goto.
- removed unneccesary cond_resched().
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Documentation/controllers/memory.txt | 3 --
mm/memcontrol.c | 48 ++++++++++++++++++++++++++++++++---
2 files changed, 45 insertions(+), 6 deletions(-)
Index: linux-2.6.26-rc8-mm1/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc8-mm1.orig/mm/memcontrol.c
+++ linux-2.6.26-rc8-mm1/mm/memcontrol.c
@@ -836,6 +836,30 @@ int mem_cgroup_shrink_usage(struct mm_st
return 0;
}
+int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
+{
+
+ int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+ int progress;
+ int ret = 0;
+
+ while (res_counter_set_limit(&memcg->res, val)) {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+ if (!retry_count) {
+ ret = -EBUSY;
+ break;
+ }
+ progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
+ if (!progress)
+ retry_count--;
+ }
+ return ret;
+}
+
+
/*
* This routine traverse page_cgroup in given list and drop them all.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
@@ -916,13 +940,29 @@ static u64 mem_cgroup_read(struct cgroup
return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
cft->private);
}
-
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
const char *buffer)
{
- return res_counter_write(&mem_cgroup_from_cont(cont)->res,
- cft->private, buffer,
- res_counter_memparse_write_strategy);
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+ unsigned long long val;
+ int ret;
+
+ switch (cft->private) {
+ case RES_LIMIT:
+ /* This function does all necessary parse...reuse it */
+ ret = res_counter_memparse_write_strategy(buffer, &val);
+ if (!ret)
+ ret = mem_cgroup_resize_limit(memcg, val);
+ break;
+ default:
+ ret = -EINVAL; /* should be BUG() ? */
+ break;
+ }
+ return ret;
}
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
Index: linux-2.6.26-rc8-mm1/Documentation/controllers/memory.txt
===================================================================
--- linux-2.6.26-rc8-mm1.orig/Documentation/controllers/memory.txt
+++ linux-2.6.26-rc8-mm1/Documentation/controllers/memory.txt
@@ -242,8 +242,7 @@ rmdir() if there are no tasks.
1. Add support for accounting huge pages (as a separate controller)
2. Make per-cgroup scanner reclaim not-shared pages first
3. Teach controller to account for shared-pages
-4. Start reclamation when the limit is lowered
-5. Start reclamation in the background when the limit is
+4. Start reclamation in the background when the limit is
not yet hit but the usage is getting closer
Summary
--
