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-rw-r--r--mm/memcontrol.c38
1 files changed, 14 insertions, 24 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e44fb0f..01c2d8f1 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1024,9 +1024,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
return NULL;
pc = lookup_page_cgroup(page);
- /*
- * Used bit of swapcache is solid under page lock.
- */
+ lock_page_cgroup(pc);
if (PageCgroupUsed(pc)) {
mem = pc->mem_cgroup;
if (mem && !css_tryget(&mem->css))
@@ -1040,6 +1038,7 @@ static struct mem_cgroup *try_get_mem_cgroup_from_swapcache(struct page *page)
mem = NULL;
rcu_read_unlock();
}
+ unlock_page_cgroup(pc);
return mem;
}
@@ -1618,37 +1617,28 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem,
}
/*
- * 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.
+ * A call to try to shrink memory usage on charge failure at shmem's swapin.
+ * Calling hierarchical_reclaim is not enough because we should update
+ * last_oom_jiffies to prevent pagefault_out_of_memory from invoking global OOM.
+ * Moreover considering hierarchy, we should reclaim from the mem_over_limit,
+ * not from the memcg which this page would be charged to.
+ * try_charge_swapin does all of these works properly.
*/
-int mem_cgroup_shrink_usage(struct page *page,
+int mem_cgroup_shmem_charge_fallback(struct page *page,
struct mm_struct *mm,
gfp_t gfp_mask)
{
struct mem_cgroup *mem = NULL;
- int progress = 0;
- int retry = MEM_CGROUP_RECLAIM_RETRIES;
+ int ret;
if (mem_cgroup_disabled())
return 0;
- if (page)
- mem = try_get_mem_cgroup_from_swapcache(page);
- if (!mem && mm)
- mem = try_get_mem_cgroup_from_mm(mm);
- if (unlikely(!mem))
- return 0;
- do {
- progress = mem_cgroup_hierarchical_reclaim(mem,
- gfp_mask, true, false);
- progress += mem_cgroup_check_under_limit(mem);
- } while (!progress && --retry);
+ ret = mem_cgroup_try_charge_swapin(mm, page, gfp_mask, &mem);
+ if (!ret)
+ mem_cgroup_cancel_charge_swapin(mem); /* it does !mem check */
- css_put(&mem->css);
- if (!retry)
- return -ENOMEM;
- return 0;
+ return ret;
}
static DEFINE_MUTEX(set_limit_mutex);
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