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authorJohannes Weiner <hannes@cmpxchg.org>2020-06-03 16:01:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-03 20:09:47 -0700
commitbe5d0a74c62d8da43f9526a5b08cdd18e2bbc37a (patch)
tree6eeb26db5ce3b90cc2e79462e60e2d8e6119d5b6 /mm/rmap.c
parent0d1c20722ab333ac0ac03ae2188922c1021d3abc (diff)
mm: memcontrol: switch to native NR_ANON_MAPPED counter
Memcg maintains a private MEMCG_RSS counter. This divergence from the generic VM accounting means unnecessary code overhead, and creates a dependency for memcg that page->mapping is set up at the time of charging, so that page types can be told apart. Convert the generic accounting sites to mod_lruvec_page_state and friends to maintain the per-cgroup vmstat counter of NR_ANON_MAPPED. We use lock_page_memcg() to stabilize page->mem_cgroup during rmap changes, the same way we do for NR_FILE_MAPPED. With the previous patch removing MEMCG_CACHE and the private NR_SHMEM counter, this patch finally eliminates the need to have page->mapping set up at charge time. However, we need to have page->mem_cgroup set up by the time rmap runs and does the accounting, so switch the commit and the rmap callbacks around. v2: fix temporary accounting bug by switching rmap<->commit (Joonsoo) Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Michal Hocko <mhocko@suse.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Balbir Singh <bsingharora@gmail.com> Link: http://lkml.kernel.org/r/20200508183105.225460-11-hannes@cmpxchg.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/rmap.c')
-rw-r--r--mm/rmap.c47
1 files changed, 29 insertions, 18 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index f79a206b271a..150513d31efa 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1114,6 +1114,11 @@ void do_page_add_anon_rmap(struct page *page,
bool compound = flags & RMAP_COMPOUND;
bool first;
+ if (unlikely(PageKsm(page)))
+ lock_page_memcg(page);
+ else
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
+
if (compound) {
atomic_t *mapcount;
VM_BUG_ON_PAGE(!PageLocked(page), page);
@@ -1134,12 +1139,13 @@ void do_page_add_anon_rmap(struct page *page,
*/
if (compound)
__inc_node_page_state(page, NR_ANON_THPS);
- __mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, nr);
+ __mod_lruvec_page_state(page, NR_ANON_MAPPED, nr);
}
- if (unlikely(PageKsm(page)))
- return;
- VM_BUG_ON_PAGE(!PageLocked(page), page);
+ if (unlikely(PageKsm(page))) {
+ unlock_page_memcg(page);
+ return;
+ }
/* address might be in next vma when migration races vma_adjust */
if (first)
@@ -1181,7 +1187,7 @@ void page_add_new_anon_rmap(struct page *page,
/* increment count (starts at -1) */
atomic_set(&page->_mapcount, 0);
}
- __mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, nr);
+ __mod_lruvec_page_state(page, NR_ANON_MAPPED, nr);
__page_set_anon_rmap(page, vma, address, 1);
}
@@ -1230,13 +1236,12 @@ static void page_remove_file_rmap(struct page *page, bool compound)
int i, nr = 1;
VM_BUG_ON_PAGE(compound && !PageHead(page), page);
- lock_page_memcg(page);
/* Hugepages are not counted in NR_FILE_MAPPED for now. */
if (unlikely(PageHuge(page))) {
/* hugetlb pages are always mapped with pmds */
atomic_dec(compound_mapcount_ptr(page));
- goto out;
+ return;
}
/* page still mapped by someone else? */
@@ -1246,14 +1251,14 @@ static void page_remove_file_rmap(struct page *page, bool compound)
nr++;
}
if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
- goto out;
+ return;
if (PageSwapBacked(page))
__dec_node_page_state(page, NR_SHMEM_PMDMAPPED);
else
__dec_node_page_state(page, NR_FILE_PMDMAPPED);
} else {
if (!atomic_add_negative(-1, &page->_mapcount))
- goto out;
+ return;
}
/*
@@ -1265,8 +1270,6 @@ static void page_remove_file_rmap(struct page *page, bool compound)
if (unlikely(PageMlocked(page)))
clear_page_mlock(page);
-out:
- unlock_page_memcg(page);
}
static void page_remove_anon_compound_rmap(struct page *page)
@@ -1310,7 +1313,7 @@ static void page_remove_anon_compound_rmap(struct page *page)
clear_page_mlock(page);
if (nr)
- __mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, -nr);
+ __mod_lruvec_page_state(page, NR_ANON_MAPPED, -nr);
}
/**
@@ -1322,22 +1325,28 @@ static void page_remove_anon_compound_rmap(struct page *page)
*/
void page_remove_rmap(struct page *page, bool compound)
{
- if (!PageAnon(page))
- return page_remove_file_rmap(page, compound);
+ lock_page_memcg(page);
- if (compound)
- return page_remove_anon_compound_rmap(page);
+ if (!PageAnon(page)) {
+ page_remove_file_rmap(page, compound);
+ goto out;
+ }
+
+ if (compound) {
+ page_remove_anon_compound_rmap(page);
+ goto out;
+ }
/* page still mapped by someone else? */
if (!atomic_add_negative(-1, &page->_mapcount))
- return;
+ goto out;
/*
* We use the irq-unsafe __{inc|mod}_zone_page_stat because
* these counters are not modified in interrupt context, and
* pte lock(a spinlock) is held, which implies preemption disabled.
*/
- __dec_node_page_state(page, NR_ANON_MAPPED);
+ __dec_lruvec_page_state(page, NR_ANON_MAPPED);
if (unlikely(PageMlocked(page)))
clear_page_mlock(page);
@@ -1354,6 +1363,8 @@ void page_remove_rmap(struct page *page, bool compound)
* Leaving it set also helps swapoff to reinstate ptes
* faster for those pages still in swapcache.
*/
+out:
+ unlock_page_memcg(page);
}
/*