From: Huang Ying <ying.huang@xxxxxxxxx>
This patch makes mem_cgroup_swapout() works for the transparent huge
page (THP). Which will move the memory cgroup charge from memory to
swap for a THP.
This will be used for the THP swap support. Where a THP may be
swapped out as a whole to a set of (HPAGE_PMD_NR) continuous swap
slots on the swap device.
Signed-off-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/memcontrol.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a627b0fd67ea..b92f3327aca2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4631,8 +4631,8 @@ static enum mc_target_type get_mctgt_type(struct vm_area_struct *vma,
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/*
- * We don't consider swapping or file mapped pages because THP does not
- * support them for now.
+ * We don't consider PMD mapped swapping or file mapped pages because THP does
+ * not support them for now.
* Caller should make sure that pmd_trans_huge(pmd) is true.
*/
static enum mc_target_type get_mctgt_type_thp(struct vm_area_struct *vma,
@@ -5890,6 +5890,7 @@ static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
{
struct mem_cgroup *memcg, *swap_memcg;
+ unsigned int nr_entries;
unsigned short oldid;
VM_BUG_ON_PAGE(PageLRU(page), page);
@@ -5910,19 +5911,24 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
* ancestor for the swap instead and transfer the memory+swap charge.
*/
swap_memcg = mem_cgroup_id_get_online(memcg);
- oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg), 1);
+ nr_entries = hpage_nr_pages(page);
+ /* Get references for the tail pages, too */
+ if (nr_entries > 1)
+ mem_cgroup_id_get_many(swap_memcg, nr_entries - 1);
+ oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg),
+ nr_entries);
VM_BUG_ON_PAGE(oldid, page);
- mem_cgroup_swap_statistics(swap_memcg, 1);
+ mem_cgroup_swap_statistics(swap_memcg, nr_entries);
page->mem_cgroup = NULL;
if (!mem_cgroup_is_root(memcg))
- page_counter_uncharge(&memcg->memory, 1);
+ page_counter_uncharge(&memcg->memory, nr_entries);
if (memcg != swap_memcg) {
if (!mem_cgroup_is_root(swap_memcg))
- page_counter_charge(&swap_memcg->memsw, 1);
- page_counter_uncharge(&memcg->memsw, 1);
+ page_counter_charge(&swap_memcg->memsw, nr_entries);
+ page_counter_uncharge(&memcg->memsw, nr_entries);
}
/*
@@ -5932,7 +5938,8 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
* only synchronisation we have for udpating the per-CPU variables.
*/
VM_BUG_ON(!irqs_disabled());
- mem_cgroup_charge_statistics(memcg, page, false, -1);
+ mem_cgroup_charge_statistics(memcg, page, PageTransHuge(page),
+ -nr_entries);
memcg_check_events(memcg, page);
if (!mem_cgroup_is_root(memcg))
--
2.13.2
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