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authorJohannes Weiner <hannes@cmpxchg.org>2020-06-04 01:02:11 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2020-06-04 05:09:48 +0200
commiteccb52e7880973f221ab2606e4d22ce04d96a1a9 (patch)
treecbc33be59949194a65a59094f6e4bff47ecf9285 /mm/memcontrol.c
parentmm: memcontrol: drop unused try/commit/cancel charge API (diff)
downloadlinux-eccb52e7880973f221ab2606e4d22ce04d96a1a9.tar.xz
linux-eccb52e7880973f221ab2606e4d22ce04d96a1a9.zip
mm: memcontrol: prepare swap controller setup for integration
A few cleanups to streamline the swap controller setup: - Replace the do_swap_account flag with cgroup_memory_noswap. This brings it in line with other functionality that is usually available unless explicitly opted out of - nosocket, nokmem. - Remove the really_do_swap_account flag that stores the boot option and is later used to switch the do_swap_account. It's not clear why this indirection is/was necessary. Use do_swap_account directly. - Minor coding style polishing Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Alex Shi <alex.shi@linux.alibaba.com> Cc: Hugh Dickins <hughd@google.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/20200508183105.225460-15-hannes@cmpxchg.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memcontrol.c')
-rw-r--r--mm/memcontrol.c59
1 files changed, 28 insertions, 31 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1e7a10b450b2..2d035e68a127 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -83,10 +83,14 @@ static bool cgroup_memory_nokmem;
/* Whether the swap controller is active */
#ifdef CONFIG_MEMCG_SWAP
-int do_swap_account __read_mostly;
+#ifdef CONFIG_MEMCG_SWAP_ENABLED
+bool cgroup_memory_noswap __read_mostly;
#else
-#define do_swap_account 0
-#endif
+bool cgroup_memory_noswap __read_mostly = 1;
+#endif /* CONFIG_MEMCG_SWAP_ENABLED */
+#else
+#define cgroup_memory_noswap 1
+#endif /* CONFIG_MEMCG_SWAP */
#ifdef CONFIG_CGROUP_WRITEBACK
static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
@@ -95,7 +99,7 @@ static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq);
/* Whether legacy memory+swap accounting is active */
static bool do_memsw_account(void)
{
- return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && do_swap_account;
+ return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && !cgroup_memory_noswap;
}
#define THRESHOLDS_EVENTS_TARGET 128
@@ -6528,18 +6532,19 @@ int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask,
/*
* Every swap fault against a single page tries to charge the
* page, bail as early as possible. shmem_unuse() encounters
- * already charged pages, too. The USED bit is protected by
- * the page lock, which serializes swap cache removal, which
+ * already charged pages, too. page->mem_cgroup is protected
+ * by the page lock, which serializes swap cache removal, which
* in turn serializes uncharging.
*/
VM_BUG_ON_PAGE(!PageLocked(page), page);
if (compound_head(page)->mem_cgroup)
goto out;
- if (do_swap_account) {
+ if (!cgroup_memory_noswap) {
swp_entry_t ent = { .val = page_private(page), };
- unsigned short id = lookup_swap_cgroup_id(ent);
+ unsigned short id;
+ id = lookup_swap_cgroup_id(ent);
rcu_read_lock();
memcg = mem_cgroup_from_id(id);
if (memcg && !css_tryget_online(&memcg->css))
@@ -7012,7 +7017,7 @@ int mem_cgroup_try_charge_swap(struct page *page, swp_entry_t entry)
struct mem_cgroup *memcg;
unsigned short oldid;
- if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) || !do_swap_account)
+ if (!cgroup_subsys_on_dfl(memory_cgrp_subsys) || cgroup_memory_noswap)
return 0;
memcg = page->mem_cgroup;
@@ -7056,7 +7061,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages)
struct mem_cgroup *memcg;
unsigned short id;
- if (!do_swap_account)
+ if (cgroup_memory_noswap)
return;
id = swap_cgroup_record(entry, 0, nr_pages);
@@ -7079,7 +7084,7 @@ long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg)
{
long nr_swap_pages = get_nr_swap_pages();
- if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
return nr_swap_pages;
for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
nr_swap_pages = min_t(long, nr_swap_pages,
@@ -7096,7 +7101,7 @@ bool mem_cgroup_swap_full(struct page *page)
if (vm_swap_full())
return true;
- if (!do_swap_account || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
+ if (cgroup_memory_noswap || !cgroup_subsys_on_dfl(memory_cgrp_subsys))
return false;
memcg = page->mem_cgroup;
@@ -7114,22 +7119,15 @@ bool mem_cgroup_swap_full(struct page *page)
return false;
}
-/* for remember boot option*/
-#ifdef CONFIG_MEMCG_SWAP_ENABLED
-static int really_do_swap_account __initdata = 1;
-#else
-static int really_do_swap_account __initdata;
-#endif
-
-static int __init enable_swap_account(char *s)
+static int __init setup_swap_account(char *s)
{
if (!strcmp(s, "1"))
- really_do_swap_account = 1;
+ cgroup_memory_noswap = 0;
else if (!strcmp(s, "0"))
- really_do_swap_account = 0;
+ cgroup_memory_noswap = 1;
return 1;
}
-__setup("swapaccount=", enable_swap_account);
+__setup("swapaccount=", setup_swap_account);
static u64 swap_current_read(struct cgroup_subsys_state *css,
struct cftype *cft)
@@ -7226,7 +7224,7 @@ static struct cftype swap_files[] = {
{ } /* terminate */
};
-static struct cftype memsw_cgroup_files[] = {
+static struct cftype memsw_files[] = {
{
.name = "memsw.usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
@@ -7255,13 +7253,12 @@ static struct cftype memsw_cgroup_files[] = {
static int __init mem_cgroup_swap_init(void)
{
- if (!mem_cgroup_disabled() && really_do_swap_account) {
- do_swap_account = 1;
- WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys,
- swap_files));
- WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys,
- memsw_cgroup_files));
- }
+ if (mem_cgroup_disabled() || cgroup_memory_noswap)
+ return 0;
+
+ WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
+ WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
+
return 0;
}
subsys_initcall(mem_cgroup_swap_init);