[PATCH 2/4] mm: memcontrol: re-use global VM event enum

From: Johannes Weiner
Date: Tue Apr 04 2017 - 18:02:05 EST


The current duplication is a high-maintenance mess, and it's painful
to add new items.

This increases the size of the event array, but we'll eventually want
most of the VM events tracked on a per-cgroup basis anyway.

Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
---
include/linux/memcontrol.h | 45 ++++++++++++---------------------------
mm/memcontrol.c | 53 ++++++++++++++++++++++++----------------------
2 files changed, 42 insertions(+), 56 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index bc0c16e284c0..0bb5f055bd26 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -69,20 +69,6 @@ struct mem_cgroup_reclaim_cookie {
unsigned int generation;
};

-enum mem_cgroup_events_index {
- MEM_CGROUP_EVENTS_PGPGIN, /* # of pages paged in */
- MEM_CGROUP_EVENTS_PGPGOUT, /* # of pages paged out */
- MEM_CGROUP_EVENTS_PGFAULT, /* # of page-faults */
- MEM_CGROUP_EVENTS_PGMAJFAULT, /* # of major page-faults */
- MEM_CGROUP_EVENTS_NSTATS,
- /* default hierarchy events */
- MEMCG_LOW = MEM_CGROUP_EVENTS_NSTATS,
- MEMCG_HIGH,
- MEMCG_MAX,
- MEMCG_OOM,
- MEMCG_NR_EVENTS,
-};
-
/*
* Per memcg event counter is incremented at every pagein/pageout. With THP,
* it will be incremated by the number of pages. This counter is used for
@@ -106,6 +92,15 @@ struct mem_cgroup_id {
atomic_t ref;
};

+/* Cgroup-specific events, on top of universal VM events */
+enum memcg_event_item {
+ MEMCG_LOW = NR_VM_EVENT_ITEMS,
+ MEMCG_HIGH,
+ MEMCG_MAX,
+ MEMCG_OOM,
+ MEMCG_NR_EVENTS,
+};
+
struct mem_cgroup_stat_cpu {
long count[MEMCG_NR_STAT];
unsigned long events[MEMCG_NR_EVENTS];
@@ -288,9 +283,9 @@ static inline bool mem_cgroup_disabled(void)
}

static inline void mem_cgroup_event(struct mem_cgroup *memcg,
- enum mem_cgroup_events_index idx)
+ enum memcg_event_item event)
{
- this_cpu_inc(memcg->stat->events[idx]);
+ this_cpu_inc(memcg->stat->events[event]);
cgroup_file_notify(&memcg->events_file);
}

@@ -575,20 +570,8 @@ static inline void mem_cgroup_count_vm_event(struct mm_struct *mm,

rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
- if (unlikely(!memcg))
- goto out;
-
- switch (idx) {
- case PGFAULT:
- this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGFAULT]);
- break;
- case PGMAJFAULT:
- this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
- break;
- default:
- BUG();
- }
-out:
+ if (likely(memcg))
+ this_cpu_inc(memcg->stat->events[idx]);
rcu_read_unlock();
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
@@ -608,7 +591,7 @@ static inline bool mem_cgroup_disabled(void)
}

static inline void mem_cgroup_event(struct mem_cgroup *memcg,
- enum mem_cgroup_events_index idx)
+ enum memcg_event_item event)
{
}

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1ffa3ad201ea..6b42887e5f14 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -111,13 +111,6 @@ static const char * const mem_cgroup_stat_names[] = {
"swap",
};

-static const char * const mem_cgroup_events_names[] = {
- "pgpgin",
- "pgpgout",
- "pgfault",
- "pgmajfault",
-};
-
static const char * const mem_cgroup_lru_names[] = {
"inactive_anon",
"active_anon",
@@ -571,13 +564,13 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
*/

static unsigned long mem_cgroup_read_events(struct mem_cgroup *memcg,
- enum mem_cgroup_events_index idx)
+ enum memcg_event_item event)
{
unsigned long val = 0;
int cpu;

for_each_possible_cpu(cpu)
- val += per_cpu(memcg->stat->events[idx], cpu);
+ val += per_cpu(memcg->stat->events[event], cpu);
return val;
}

@@ -608,9 +601,9 @@ static void mem_cgroup_charge_statistics(struct mem_cgroup *memcg,

/* pagein of a big page is an event. So, ignore page size */
if (nr_pages > 0)
- __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGIN]);
+ __this_cpu_inc(memcg->stat->events[PGPGIN]);
else {
- __this_cpu_inc(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT]);
+ __this_cpu_inc(memcg->stat->events[PGPGOUT]);
nr_pages = -nr_pages; /* for event */
}

@@ -3119,6 +3112,21 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v)
}
#endif /* CONFIG_NUMA */

+/* Universal VM events cgroup1 shows, original sort order */
+unsigned int memcg1_events[] = {
+ PGPGIN,
+ PGPGOUT,
+ PGFAULT,
+ PGMAJFAULT,
+};
+
+static const char *const memcg1_event_names[] = {
+ "pgpgin",
+ "pgpgout",
+ "pgfault",
+ "pgmajfault",
+};
+
static int memcg_stat_show(struct seq_file *m, void *v)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
@@ -3128,8 +3136,6 @@ static int memcg_stat_show(struct seq_file *m, void *v)

BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_stat_names) !=
MEM_CGROUP_STAT_NSTATS);
- BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_events_names) !=
- MEM_CGROUP_EVENTS_NSTATS);
BUILD_BUG_ON(ARRAY_SIZE(mem_cgroup_lru_names) != NR_LRU_LISTS);

for (i = 0; i < MEM_CGROUP_STAT_NSTATS; i++) {
@@ -3139,9 +3145,9 @@ static int memcg_stat_show(struct seq_file *m, void *v)
mem_cgroup_read_stat(memcg, i) * PAGE_SIZE);
}

- for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++)
- seq_printf(m, "%s %lu\n", mem_cgroup_events_names[i],
- mem_cgroup_read_events(memcg, i));
+ for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
+ seq_printf(m, "%s %lu\n", memcg1_event_names[i],
+ mem_cgroup_read_events(memcg, memcg1_events[i]));

for (i = 0; i < NR_LRU_LISTS; i++)
seq_printf(m, "%s %lu\n", mem_cgroup_lru_names[i],
@@ -3169,13 +3175,12 @@ static int memcg_stat_show(struct seq_file *m, void *v)
seq_printf(m, "total_%s %llu\n", mem_cgroup_stat_names[i], val);
}

- for (i = 0; i < MEM_CGROUP_EVENTS_NSTATS; i++) {
+ for (i = 0; i < ARRAY_SIZE(memcg1_events); i++) {
unsigned long long val = 0;

for_each_mem_cgroup_tree(mi, memcg)
- val += mem_cgroup_read_events(mi, i);
- seq_printf(m, "total_%s %llu\n",
- mem_cgroup_events_names[i], val);
+ val += mem_cgroup_read_events(mi, memcg1_events[i]);
+ seq_printf(m, "total_%s %llu\n", memcg1_event_names[i], val);
}

for (i = 0; i < NR_LRU_LISTS; i++) {
@@ -5222,10 +5227,8 @@ static int memory_stat_show(struct seq_file *m, void *v)

/* Accumulated memory events */

- seq_printf(m, "pgfault %lu\n",
- events[MEM_CGROUP_EVENTS_PGFAULT]);
- seq_printf(m, "pgmajfault %lu\n",
- events[MEM_CGROUP_EVENTS_PGMAJFAULT]);
+ seq_printf(m, "pgfault %lu\n", events[PGFAULT]);
+ seq_printf(m, "pgmajfault %lu\n", events[PGMAJFAULT]);

seq_printf(m, "workingset_refault %lu\n",
stat[MEMCG_WORKINGSET_REFAULT]);
@@ -5493,7 +5496,7 @@ static void uncharge_batch(struct mem_cgroup *memcg, unsigned long pgpgout,
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_CACHE], nr_file);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_RSS_HUGE], nr_huge);
__this_cpu_sub(memcg->stat->count[MEM_CGROUP_STAT_SHMEM], nr_shmem);
- __this_cpu_add(memcg->stat->events[MEM_CGROUP_EVENTS_PGPGOUT], pgpgout);
+ __this_cpu_add(memcg->stat->events[PGPGOUT], pgpgout);
__this_cpu_add(memcg->stat->nr_page_events, nr_pages);
memcg_check_events(memcg, dummy_page);
local_irq_restore(flags);
--
2.12.1