A new call, mem_cgroup_shrink_usage() is added for shmem handling
and removing not usual usage of mem_cgroup_charge/uncharge.
Now, shmem calls mem_cgroup_charge() just for reclaim some pages from
mem_cgroup. In general, shmem is used by some process group and not for
global resource (like file caches). So, it's reasonable to reclaim pages from
mem_cgroup where shmem is mainly used.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
mm/memcontrol.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
Index: linux-2.6.26-rc2/mm/memcontrol.c
===================================================================
--- linux-2.6.26-rc2.orig/mm/memcontrol.c
+++ linux-2.6.26-rc2/mm/memcontrol.c
@@ -783,6 +783,30 @@ static void mem_cgroup_drop_all_pages(st
}
/*
+ * A call to try to shrink memory usage under specified resource controller.
+ * This is typically used for page reclaiming for shmem for reducing side
+ * effect of page allocation from shmem, which is used by some mem_cgroup.
+ */
+int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
+{
+ struct mem_cgroup *mem;
+ int progress = 0;
+ int retry = MEM_CGROUP_RECLAIM_RETRIES;
+
+ rcu_read_lock();
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ css_get(&mem->css);
+ rcu_read_unlock();
+
+ while(!progress && --retry) {
+ progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+ }
+ if (!retry)
+ return -ENOMEM;
+ return 0;
+}
+
+/*
* This routine traverse page_cgroup in given list and drop them all.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
*/
Index: linux-2.6.26-rc2/mm/shmem.c
===================================================================
--- linux-2.6.26-rc2.orig/mm/shmem.c
+++ linux-2.6.26-rc2/mm/shmem.c
@@ -1314,13 +1314,12 @@ repeat:
unlock_page(swappage);
if (error == -ENOMEM) {
/* allow reclaim from this memory cgroup */
- error = mem_cgroup_cache_charge(swappage,
- current->mm, gfp & ~__GFP_HIGHMEM);
+ error = mem_cgroup_shrink_usage(current->mm,
+ gfp & ~__GFP_HIGHMEM);
if (error) {
page_cache_release(swappage);
goto failed;
}
- mem_cgroup_uncharge_cache_page(swappage);
}
page_cache_release(swappage);
goto repeat;
--
