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Commit d6810d73 authored by Huang Ying's avatar Huang Ying Committed by Linus Torvalds
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memcg, THP, swap: make mem_cgroup_swapout() support THP 

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.

Link: http://lkml.kernel.org/r/20170724051840.2309-11-ying.huang@intel.com


Signed-off-by: default avatar"Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Rik van Riel <riel@redhat.com>
Cc: Ross Zwisler <ross.zwisler@intel.com> [for brd.c, zram_drv.c, pmem.c]
Cc: Shaohua Li <shli@kernel.org>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent abe2895b

mm/memcontrol.c

+15 −8
Original line number Diff line number Diff line
@@ -4654,8 +4654,8 @@ 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,
@@ -5913,6 +5913,7 @@ 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);
@@ -5933,19 +5934,24 @@ 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);

	}



	/*
@@ -5955,7 +5961,8 @@ 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))