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: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 08ef3d2..6903e7d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -87,6 +87,12 @@
#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 @@
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 @@
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 @@
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 @@
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 @@
* 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 @@
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 @@
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 @@
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 @@
}
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 @@
{
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 @@
* 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
struct mem_cgroup *memcg;
unsigned short id;
- if (!do_swap_account)
+ if (!do_memsw_account())
return;
id = swap_cgroup_record(entry, 0);