memcg: handle swap caches

[mirror_ubuntu-zesty-kernel.git] / mm / memcontrol.c

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index decace3bb57eb4b0f0f36d09e1758b4c7d78df33..7288e9d85ca78f65cf084536b01da91dbbbfa594 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -21,6 +21,7 @@
 #include <linux/memcontrol.h>
 #include <linux/cgroup.h>
 #include <linux/mm.h>
+#include <linux/pagemap.h>
 #include <linux/smp.h>
 #include <linux/page-flags.h>
 #include <linux/backing-dev.h>
@@ -139,6 +140,7 @@ enum charge_type {
        MEM_CGROUP_CHARGE_TYPE_MAPPED,
        MEM_CGROUP_CHARGE_TYPE_SHMEM,   /* used by page migration of shmem */
        MEM_CGROUP_CHARGE_TYPE_FORCE,   /* used by force_empty */
+       MEM_CGROUP_CHARGE_TYPE_SWAPOUT, /* for accounting swapcache */
        NR_CHARGE_TYPE,
 };
 
@@ -780,6 +782,33 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
                                MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
 }
 
+#ifdef CONFIG_SWAP
+int mem_cgroup_cache_charge_swapin(struct page *page,
+                       struct mm_struct *mm, gfp_t mask, bool locked)
+{
+       int ret = 0;
+
+       if (mem_cgroup_subsys.disabled)
+               return 0;
+       if (unlikely(!mm))
+               mm = &init_mm;
+       if (!locked)
+               lock_page(page);
+       /*
+        * If not locked, the page can be dropped from SwapCache until
+        * we reach here.
+        */
+       if (PageSwapCache(page)) {
+               ret = mem_cgroup_charge_common(page, mm, mask,
+                               MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
+       }
+       if (!locked)
+               unlock_page(page);
+
+       return ret;
+}
+#endif
+
 void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
 {
        struct page_cgroup *pc;
@@ -817,6 +846,9 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
        if (mem_cgroup_subsys.disabled)
                return;
 
+       if (PageSwapCache(page))
+               return;
+
        /*
         * Check if our page_cgroup is valid
         */
@@ -825,12 +857,26 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
                return;
 
        lock_page_cgroup(pc);
-       if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED && page_mapped(page))
-            || !PageCgroupUsed(pc)) {
-               /* This happens at race in zap_pte_range() and do_swap_page()*/
-               unlock_page_cgroup(pc);
-               return;
+
+       if (!PageCgroupUsed(pc))
+               goto unlock_out;
+
+       switch (ctype) {
+       case MEM_CGROUP_CHARGE_TYPE_MAPPED:
+               if (page_mapped(page))
+                       goto unlock_out;
+               break;
+       case MEM_CGROUP_CHARGE_TYPE_SWAPOUT:
+               if (!PageAnon(page)) {  /* Shared memory */
+                       if (page->mapping && !page_is_file_cache(page))
+                               goto unlock_out;
+               } else if (page_mapped(page)) /* Anon */
+                               goto unlock_out;
+               break;
+       default:
+               break;
        }
+
        ClearPageCgroupUsed(pc);
        mem = pc->mem_cgroup;
 
@@ -844,6 +890,10 @@ __mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
        css_put(&mem->css);
 
        return;
+
+unlock_out:
+       unlock_page_cgroup(pc);
+       return;
 }
 
 void mem_cgroup_uncharge_page(struct page *page)
@@ -863,6 +913,11 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
        __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
 }
 
+void mem_cgroup_uncharge_swapcache(struct page *page)
+{
+       __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_SWAPOUT);
+}
+
 /*
  * Before starting migration, account PAGE_SIZE to mem_cgroup that the old
  * page belongs to.
@@ -920,7 +975,7 @@ void mem_cgroup_end_migration(struct mem_cgroup *mem,
                ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
 
        /* unused page is not on radix-tree now. */
-       if (unused && ctype != MEM_CGROUP_CHARGE_TYPE_MAPPED)
+       if (unused)
                __mem_cgroup_uncharge_common(unused, ctype);
 
        pc = lookup_page_cgroup(target);