memcg: avoid accounting special pages
There are not-on-LRU pages which can be mapped and they are not worth to
be accounted. (becasue we can't shrink them and need dirty codes to
handle specical case) We'd like to make use of usual objrmap/radix-tree's
protcol and don't want to account out-of-vm's control pages.
When special_mapping_fault() is called, page->mapping is tend to be NULL
and it's charged as Anonymous page. insert_page() also handles some
special pages from drivers.
This patch is for avoiding to account special pages.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index 54cf20e..3a6c4a6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1323,18 +1323,14 @@
pte_t *pte;
spinlock_t *ptl;
- retval = mem_cgroup_charge(page, mm, GFP_KERNEL);
- if (retval)
- goto out;
-
retval = -EINVAL;
if (PageAnon(page))
- goto out_uncharge;
+ goto out;
retval = -ENOMEM;
flush_dcache_page(page);
pte = get_locked_pte(mm, addr, &ptl);
if (!pte)
- goto out_uncharge;
+ goto out;
retval = -EBUSY;
if (!pte_none(*pte))
goto out_unlock;
@@ -1350,8 +1346,6 @@
return retval;
out_unlock:
pte_unmap_unlock(pte, ptl);
-out_uncharge:
- mem_cgroup_uncharge_page(page);
out:
return retval;
}
@@ -2463,6 +2457,7 @@
struct page *page;
pte_t entry;
int anon = 0;
+ int charged = 0;
struct page *dirty_page = NULL;
struct vm_fault vmf;
int ret;
@@ -2503,6 +2498,12 @@
ret = VM_FAULT_OOM;
goto out;
}
+ if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
+ ret = VM_FAULT_OOM;
+ page_cache_release(page);
+ goto out;
+ }
+ charged = 1;
/*
* Don't let another task, with possibly unlocked vma,
* keep the mlocked page.
@@ -2543,11 +2544,6 @@
}
- if (mem_cgroup_charge(page, mm, GFP_KERNEL)) {
- ret = VM_FAULT_OOM;
- goto out;
- }
-
page_table = pte_offset_map_lock(mm, pmd, address, &ptl);
/*
@@ -2585,7 +2581,8 @@
/* no need to invalidate: a not-present page won't be cached */
update_mmu_cache(vma, address, entry);
} else {
- mem_cgroup_uncharge_page(page);
+ if (charged)
+ mem_cgroup_uncharge_page(page);
if (anon)
page_cache_release(page);
else