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Commit 7941d214 authored by Johannes Weiner's avatar Johannes Weiner Committed by Linus Torvalds
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mm: memcontrol: do not account memory+swap on unified hierarchy 



The unified hierarchy memory controller doesn't expose the memory+swap
counter to userspace, but its accounting is hardcoded in all charge
paths right now, including the per-cpu charge cache ("the stock").

To avoid adding yet more pointless memory+swap accounting with the
socket memory support in unified hierarchy, disable the counter
altogether when in unified hierarchy mode.

Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Reviewed-by: default avatarVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 80e95fe0

mm/memcontrol.c

+25 −19
Original line number Diff line number Diff line
@@ -87,6 +87,12 @@ int do_swap_account __read_mostly; 
#define do_swap_account		0

#endif



/* Whether legacy memory+swap accounting is active */

static bool do_memsw_account(void)

{

	return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && do_swap_account;

}



static const char * const mem_cgroup_stat_names[] = {

	"cache",

	"rss",
@@ -1199,7 +1205,7 @@ static unsigned long mem_cgroup_margin(struct mem_cgroup *memcg) 
	if (count < limit)

		margin = limit - count;



	if (do_swap_account) {

	if (do_memsw_account()) {

		count = page_counter_read(&memcg->memsw);

		limit = READ_ONCE(memcg->memsw.limit);

		if (count <= limit)
@@ -1302,7 +1308,7 @@ void mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p) 
		pr_cont(":");



		for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {

			if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)

			if (i == MEM_CGROUP_STAT_SWAP && !do_memsw_account())

				continue;

			pr_cont(" %s:%luKB", mem_cgroup_stat_names[i],

				K(mem_cgroup_read_stat(iter, i)));
@@ -1925,7 +1931,7 @@ static void drain_stock(struct memcg_stock_pcp *stock) 


	if (stock->nr_pages) {

		page_counter_uncharge(&old->memory, stock->nr_pages);

		if (do_swap_account)

		if (do_memsw_account())

			page_counter_uncharge(&old->memsw, stock->nr_pages);

		css_put_many(&old->css, stock->nr_pages);

		stock->nr_pages = 0;
@@ -2055,11 +2061,11 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, 
	if (consume_stock(memcg, nr_pages))

		return 0;



	if (!do_swap_account ||

	if (!do_memsw_account() ||

	    page_counter_try_charge(&memcg->memsw, batch, &counter)) {

		if (page_counter_try_charge(&memcg->memory, batch, &counter))

			goto done_restock;

		if (do_swap_account)

		if (do_memsw_account())

			page_counter_uncharge(&memcg->memsw, batch);

		mem_over_limit = mem_cgroup_from_counter(counter, memory);

	} else {
@@ -2146,7 +2152,7 @@ static int try_charge(struct mem_cgroup *memcg, gfp_t gfp_mask, 
	 * temporarily by force charging it.

	 */

	page_counter_charge(&memcg->memory, nr_pages);

	if (do_swap_account)

	if (do_memsw_account())

		page_counter_charge(&memcg->memsw, nr_pages);

	css_get_many(&memcg->css, nr_pages);
@@ -2183,7 +2189,7 @@ static void cancel_charge(struct mem_cgroup *memcg, unsigned int nr_pages) 
		return;



	page_counter_uncharge(&memcg->memory, nr_pages);

	if (do_swap_account)

	if (do_memsw_account())

		page_counter_uncharge(&memcg->memsw, nr_pages);



	css_put_many(&memcg->css, nr_pages);
@@ -2469,7 +2475,7 @@ void __memcg_kmem_uncharge(struct page *page, int order) 


	page_counter_uncharge(&memcg->kmem, nr_pages);

	page_counter_uncharge(&memcg->memory, nr_pages);

	if (do_swap_account)

	if (do_memsw_account())

		page_counter_uncharge(&memcg->memsw, nr_pages);



	page->mem_cgroup = NULL;
@@ -3184,7 +3190,7 @@ static int memcg_stat_show(struct seq_file *m, void *v) 
	BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);



	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {

		if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)

		if (i == MEM_CGROUP_STAT_SWAP && !do_memsw_account())

			continue;

		seq_printf(m, "%s %lu\n", mem_cgroup_stat_names[i],

			   mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
@@ -3206,14 +3212,14 @@ static int memcg_stat_show(struct seq_file *m, void *v) 
	}

	seq_printf(m, "hierarchical_memory_limit %llu\n",

		   (u64)memory * PAGE_SIZE);

	if (do_swap_account)

	if (do_memsw_account())

		seq_printf(m, "hierarchical_memsw_limit %llu\n",

			   (u64)memsw * PAGE_SIZE);



	for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {

		unsigned long long val = 0;



		if (i == MEM_CGROUP_STAT_SWAP && !do_swap_account)

		if (i == MEM_CGROUP_STAT_SWAP && !do_memsw_account())

			continue;

		for_each_mem_cgroup_tree(mi, memcg)

			val += mem_cgroup_read_stat(mi, i) * PAGE_SIZE;
@@ -3344,7 +3350,7 @@ static void mem_cgroup_threshold(struct mem_cgroup *memcg) 
{

	while (memcg) {

		__mem_cgroup_threshold(memcg, false);

		if (do_swap_account)

		if (do_memsw_account())

			__mem_cgroup_threshold(memcg, true);



		memcg = parent_mem_cgroup(memcg);
@@ -4497,7 +4503,7 @@ static struct page *mc_handle_swap_pte(struct vm_area_struct *vma, 
	 * we call find_get_page() with swapper_space directly.

	 */

	page = find_get_page(swap_address_space(ent), ent.val);

	if (do_swap_account)

	if (do_memsw_account())

		entry->val = ent.val;



	return page;
@@ -4532,7 +4538,7 @@ static struct page *mc_handle_file_pte(struct vm_area_struct *vma, 
		page = find_get_entry(mapping, pgoff);

		if (radix_tree_exceptional_entry(page)) {

			swp_entry_t swp = radix_to_swp_entry(page);

			if (do_swap_account)

			if (do_memsw_account())

				*entry = swp;

			page = find_get_page(swap_address_space(swp), swp.val);

		}
@@ -5325,7 +5331,7 @@ int mem_cgroup_try_charge(struct page *page, struct mm_struct *mm, 
		if (page->mem_cgroup)

			goto out;



		if (do_swap_account) {

		if (do_memsw_account()) {

			swp_entry_t ent = { .val = page_private(page), };

			unsigned short id = lookup_swap_cgroup_id(ent);
@@ -5399,7 +5405,7 @@ void mem_cgroup_commit_charge(struct page *page, struct mem_cgroup *memcg, 
	memcg_check_events(memcg, page);

	local_irq_enable();



	if (do_swap_account && PageSwapCache(page)) {

	if (do_memsw_account() && PageSwapCache(page)) {

		swp_entry_t entry = { .val = page_private(page) };

		/*

		 * The swap entry might not get freed for a long time,
@@ -5448,7 +5454,7 @@ static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout, 


	if (!mem_cgroup_is_root(memcg)) {

		page_counter_uncharge(&memcg->memory, nr_pages);

		if (do_swap_account)

		if (do_memsw_account())

			page_counter_uncharge(&memcg->memsw, nr_pages);

		memcg_oom_recover(memcg);

	}
@@ -5656,7 +5662,7 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry) 
	VM_BUG_ON_PAGE(PageLRU(page), page);

	VM_BUG_ON_PAGE(page_count(page), page);



	if (!do_swap_account)

	if (!do_memsw_account())

		return;



	memcg = page->mem_cgroup;
@@ -5696,7 +5702,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry) 
	struct mem_cgroup *memcg;

	unsigned short id;



	if (!do_swap_account)

	if (!do_memsw_account())

		return;



	id = swap_cgroup_record(entry, 0);