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mm: memcontrol: prepare swap controller setup for integration

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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>
This commit is contained in:
Johannes Weiner 2020-06-03 16:02:11 -07:00 committed by Linus Torvalds
parent f0e45fb4da
commit eccb52e788
3 changed files with 31 additions and 34 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/memcontrol.h
View File

@ -558,7 +558,7 @@ struct mem_cgroup *mem_cgroup_get_oom_group(struct task_struct *victim,
void mem_cgroup_print_oom_group(struct mem_cgroup *memcg); void mem_cgroup_print_oom_group(struct mem_cgroup *memcg);
#ifdef CONFIG_MEMCG_SWAP #ifdef CONFIG_MEMCG_SWAP
extern int do_swap_account; extern bool cgroup_memory_noswap;
#endif #endif
struct mem_cgroup *lock_page_memcg(struct page *page); struct mem_cgroup *lock_page_memcg(struct page *page);

59
mm/memcontrol.c
View File

@ -83,10 +83,14 @@ static bool cgroup_memory_nokmem;
/* Whether the swap controller is active */ /* Whether the swap controller is active */
#ifdef CONFIG_MEMCG_SWAP #ifdef CONFIG_MEMCG_SWAP
int do_swap_account __read_mostly; #ifdef CONFIG_MEMCG_SWAP_ENABLED
bool cgroup_memory_noswap __read_mostly;
#else #else
#define do_swap_account 0 bool cgroup_memory_noswap __read_mostly = 1;
#endif #endif /* CONFIG_MEMCG_SWAP_ENABLED */
#else
#define cgroup_memory_noswap 1
#endif /* CONFIG_MEMCG_SWAP */
#ifdef CONFIG_CGROUP_WRITEBACK #ifdef CONFIG_CGROUP_WRITEBACK
static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); 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 */ /* Whether legacy memory+swap accounting is active */
static bool do_memsw_account(void) 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 #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 * Every swap fault against a single page tries to charge the
* page, bail as early as possible. shmem_unuse() encounters * page, bail as early as possible. shmem_unuse() encounters
* already charged pages, too. The USED bit is protected by * already charged pages, too. page->mem_cgroup is protected
* the page lock, which serializes swap cache removal, which * by the page lock, which serializes swap cache removal, which
* in turn serializes uncharging. * in turn serializes uncharging.
*/ */
VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(!PageLocked(page), page);
if (compound_head(page)->mem_cgroup) if (compound_head(page)->mem_cgroup)
goto out; goto out;
if (do_swap_account) { if (!cgroup_memory_noswap) {
swp_entry_t ent = { .val = page_private(page), }; 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(); rcu_read_lock();
memcg = mem_cgroup_from_id(id); memcg = mem_cgroup_from_id(id);
if (memcg && !css_tryget_online(&memcg->css)) 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; struct mem_cgroup *memcg;
unsigned short oldid; 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; return 0;
memcg = page->mem_cgroup; 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; struct mem_cgroup *memcg;
unsigned short id; unsigned short id;
if (!do_swap_account) if (cgroup_memory_noswap)
return; return;
id = swap_cgroup_record(entry, 0, nr_pages); 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(); 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; return nr_swap_pages;
for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg))
nr_swap_pages = min_t(long, nr_swap_pages, 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()) if (vm_swap_full())
return true; 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; return false;
memcg = page->mem_cgroup; memcg = page->mem_cgroup;
@ -7114,22 +7119,15 @@ bool mem_cgroup_swap_full(struct page *page)
return false; return false;
} }
/* for remember boot option*/ static int __init setup_swap_account(char *s)
#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)
{ {
if (!strcmp(s, "1")) if (!strcmp(s, "1"))
really_do_swap_account = 1; cgroup_memory_noswap = 0;
else if (!strcmp(s, "0")) else if (!strcmp(s, "0"))
really_do_swap_account = 0; cgroup_memory_noswap = 1;
return 1; return 1;
} }
__setup("swapaccount=", enable_swap_account); __setup("swapaccount=", setup_swap_account);
static u64 swap_current_read(struct cgroup_subsys_state *css, static u64 swap_current_read(struct cgroup_subsys_state *css,
struct cftype *cft) struct cftype *cft)
@ -7226,7 +7224,7 @@ static struct cftype swap_files[] = {
{ } /* terminate */ { } /* terminate */
}; };
static struct cftype memsw_cgroup_files[] = { static struct cftype memsw_files[] = {
{ {
.name = "memsw.usage_in_bytes", .name = "memsw.usage_in_bytes",
.private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE), .private = MEMFILE_PRIVATE(_MEMSWAP, RES_USAGE),
@ -7255,13 +7253,12 @@ static struct cftype memsw_cgroup_files[] = {
static int __init mem_cgroup_swap_init(void) static int __init mem_cgroup_swap_init(void)
{ {
if (!mem_cgroup_disabled() && really_do_swap_account) { if (mem_cgroup_disabled() || cgroup_memory_noswap)
do_swap_account = 1; return 0;
WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys,
swap_files)); WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files));
WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files));
memsw_cgroup_files));
}
return 0; return 0;
} }
subsys_initcall(mem_cgroup_swap_init); subsys_initcall(mem_cgroup_swap_init);

4
mm/swap_cgroup.c
View File

@ -171,7 +171,7 @@ int swap_cgroup_swapon(int type, unsigned long max_pages)
unsigned long length; unsigned long length;
struct swap_cgroup_ctrl *ctrl; struct swap_cgroup_ctrl *ctrl;
if (!do_swap_account) if (cgroup_memory_noswap)
return 0; return 0;
length = DIV_ROUND_UP(max_pages, SC_PER_PAGE); length = DIV_ROUND_UP(max_pages, SC_PER_PAGE);
@ -209,7 +209,7 @@ void swap_cgroup_swapoff(int type)
unsigned long i, length; unsigned long i, length;
struct swap_cgroup_ctrl *ctrl; struct swap_cgroup_ctrl *ctrl;
if (!do_swap_account) if (cgroup_memory_noswap)
return; return;
mutex_lock(&swap_cgroup_mutex); mutex_lock(&swap_cgroup_mutex);