From: Kaiyang Zhao <kaiyang2@xxxxxxxxxx>
The ability to observe the demotion and promotion decisions made by the
kernel on a per-cgroup basis is important for monitoring and tuning
containerized workloads on either NUMA machines or machines
equipped with tiered memory.
Different containers in the system may experience drastically different
memory tiering actions that cannot be distinguished from the global
counters alone.
For example, a container running a workload that has a much hotter
memory accesses will likely see more promotions and fewer demotions,
potentially depriving a colocated container of top tier memory to such
an extent that its performance degrades unacceptably.
For another example, some containers may exhibit longer periods between
data reuse, causing much more numa_hint_faults than numa_pages_migrated.
In this case, tuning hot_threshold_ms may be appropriate, but the signal
can easily be lost if only global counters are available.
This patch set adds five counters to
memory.stat in a cgroup: numa_pages_migrated, numa_pte_updates,
numa_hint_faults, pgdemote_kswapd and pgdemote_direct.
count_memcg_events_mm() is added to count multiple event occurrences at
once, and get_mem_cgroup_from_folio() is added because we need to get a
reference to the memcg of a folio before it's migrated to track
numa_pages_migrated. The accounting of PGDEMOTE_* is moved to
shrink_inactive_list() before being changed to per-cgroup.
Signed-off-by: Kaiyang Zhao <kaiyang2@xxxxxxxxxx>
---
include/linux/memcontrol.h | 24 +++++++++++++++++++++---
include/linux/vmstat.h | 1 +
mm/memcontrol.c | 32 ++++++++++++++++++++++++++++++++
mm/memory.c | 1 +
mm/mempolicy.c | 4 +++-
mm/migrate.c | 3 +++
mm/vmscan.c | 8 ++++----
7 files changed, 65 insertions(+), 8 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 44f7fb7dc0c8..90ecd2dbca06 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -768,6 +768,8 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_struct *mm);
struct mem_cgroup *get_mem_cgroup_from_current(void);
+struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio);
+
struct lruvec *folio_lruvec_lock(struct folio *folio);
struct lruvec *folio_lruvec_lock_irq(struct folio *folio);
struct lruvec *folio_lruvec_lock_irqsave(struct folio *folio,
@@ -1012,8 +1014,8 @@ static inline void count_memcg_folio_events(struct folio *folio,
count_memcg_events(memcg, idx, nr);
}
-static inline void count_memcg_event_mm(struct mm_struct *mm,
- enum vm_event_item idx)
+static inline void count_memcg_events_mm(struct mm_struct *mm,
+ enum vm_event_item idx, unsigned long count)
{
struct mem_cgroup *memcg;
@@ -1023,10 +1025,16 @@ static inline void count_memcg_event_mm(struct mm_struct *mm,
rcu_read_lock();
memcg = mem_cgroup_from_task(rcu_dereference(mm->owner));
if (likely(memcg))
- count_memcg_events(memcg, idx, 1);
+ count_memcg_events(memcg, idx, count);
rcu_read_unlock();
}
+static inline void count_memcg_event_mm(struct mm_struct *mm,
+ enum vm_event_item idx)
+{
+ count_memcg_events_mm(mm, idx, 1);
+}
+
static inline void memcg_memory_event(struct mem_cgroup *memcg,
enum memcg_memory_event event)
{
@@ -1246,6 +1254,11 @@ static inline struct mem_cgroup *get_mem_cgroup_from_current(void)
return NULL;
}
+static inline struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio)
+{
+ return NULL;
+}
+
static inline
struct mem_cgroup *mem_cgroup_from_css(struct cgroup_subsys_state *css)
{
@@ -1468,6 +1481,11 @@ static inline void count_memcg_folio_events(struct folio *folio,
{
}
+static inline void count_memcg_events_mm(struct mm_struct *mm,
+ enum vm_event_item idx, unsigned long count)
+{
+}
+
static inline
void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
{
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index 596c050ed492..ff0b49f76ca4 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -32,6 +32,7 @@ struct reclaim_stat {
unsigned nr_ref_keep;
unsigned nr_unmap_fail;
unsigned nr_lazyfree_fail;
+ unsigned nr_demoted;
};
/* Stat data for system wide items */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e1ffd2950393..e8e59d3729c0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -307,6 +307,9 @@ static const unsigned int memcg_node_stat_items[] = {
#ifdef CONFIG_SWAP
NR_SWAPCACHE,
#endif
+ PGDEMOTE_KSWAPD,
+ PGDEMOTE_DIRECT,
+ PGDEMOTE_KHUGEPAGED,
};
static const unsigned int memcg_stat_items[] = {
@@ -437,6 +440,11 @@ static const unsigned int memcg_vm_event_stat[] = {
THP_SWPOUT,
THP_SWPOUT_FALLBACK,
#endif
+#ifdef CONFIG_NUMA_BALANCING
+ NUMA_PAGE_MIGRATE,
+ NUMA_PTE_UPDATES,
+ NUMA_HINT_FAULTS,
+#endif
};
#define NR_MEMCG_EVENTS ARRAY_SIZE(memcg_vm_event_stat)
@@ -978,6 +986,23 @@ struct mem_cgroup *get_mem_cgroup_from_current(void)
return memcg;
}
+/**
+ * get_mem_cgroup_from_folio - Obtain a reference on a given folio's memcg.
+ */
+struct mem_cgroup *get_mem_cgroup_from_folio(struct folio *folio)
+{
+ struct mem_cgroup *memcg = folio_memcg(folio);
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ rcu_read_lock();
+ if (!memcg || WARN_ON_ONCE(!css_tryget(&memcg->css)))
+ memcg = root_mem_cgroup;
+ rcu_read_unlock();
+ return memcg;
+}
+
/**
* mem_cgroup_iter - iterate over memory cgroup hierarchy
* @root: hierarchy root
@@ -1383,6 +1408,10 @@ static const struct memory_stat memory_stats[] = {
{ "workingset_restore_anon", WORKINGSET_RESTORE_ANON },
{ "workingset_restore_file", WORKINGSET_RESTORE_FILE },
{ "workingset_nodereclaim", WORKINGSET_NODERECLAIM },
+
+ { "pgdemote_kswapd", PGDEMOTE_KSWAPD },
+ { "pgdemote_direct", PGDEMOTE_DIRECT },
+ { "pgdemote_khugepaged", PGDEMOTE_KHUGEPAGED },
};
/* The actual unit of the state item, not the same as the output unit */
@@ -1416,6 +1445,9 @@ static int memcg_page_state_output_unit(int item)
case WORKINGSET_RESTORE_ANON:
case WORKINGSET_RESTORE_FILE:
case WORKINGSET_NODERECLAIM:
+ case PGDEMOTE_KSWAPD:
+ case PGDEMOTE_DIRECT:
+ case PGDEMOTE_KHUGEPAGED:
return 1;
default:
return memcg_page_state_unit(item);
diff --git a/mm/memory.c b/mm/memory.c
index d6af095d255b..7d69c0287b24 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5373,6 +5373,7 @@ int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf,
vma_set_access_pid_bit(vma);
count_vm_numa_event(NUMA_HINT_FAULTS);
+ count_memcg_folio_events(folio, NUMA_HINT_FAULTS, 1);
if (page_nid == numa_node_id()) {
count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
*flags |= TNF_FAULT_LOCAL;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index b3b5f376471f..b646fab3e45e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -676,8 +676,10 @@ unsigned long change_prot_numa(struct vm_area_struct *vma,
tlb_gather_mmu(&tlb, vma->vm_mm);
nr_updated = change_protection(&tlb, vma, addr, end, MM_CP_PROT_NUMA);
- if (nr_updated > 0)
+ if (nr_updated > 0) {
count_vm_numa_events(NUMA_PTE_UPDATES, nr_updated);
+ count_memcg_events_mm(vma->vm_mm, NUMA_PTE_UPDATES, nr_updated);
+ }
tlb_finish_mmu(&tlb);
diff --git a/mm/migrate.c b/mm/migrate.c
index 66a5f73ebfdf..7e1267042a56 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2614,6 +2614,7 @@ int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma,
int nr_remaining;
unsigned int nr_succeeded;
LIST_HEAD(migratepages);
+ struct mem_cgroup *memcg = get_mem_cgroup_from_folio(folio);
list_add(&folio->lru, &migratepages);
nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_folio,
@@ -2623,12 +2624,14 @@ int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma,
putback_movable_pages(&migratepages);
if (nr_succeeded) {
count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded);
+ count_memcg_events(memcg, NUMA_PAGE_MIGRATE, nr_succeeded);
if ((sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING)
&& !node_is_toptier(folio_nid(folio))
&& node_is_toptier(node))
mod_node_page_state(pgdat, PGPROMOTE_SUCCESS,
nr_succeeded);
}
+ mem_cgroup_put(memcg);
BUG_ON(!list_empty(&migratepages));
return nr_remaining ? -EAGAIN : 0;
}
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 25e43bb3b574..fd66789a413b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1008,9 +1008,6 @@ static unsigned int demote_folio_list(struct list_head *demote_folios,
(unsigned long)&mtc, MIGRATE_ASYNC, MR_DEMOTION,
&nr_succeeded);
- mod_node_page_state(pgdat, PGDEMOTE_KSWAPD + reclaimer_offset(),
- nr_succeeded);
-
return nr_succeeded;
}
@@ -1518,7 +1515,8 @@ static unsigned int shrink_folio_list(struct list_head *folio_list,
/* 'folio_list' is always empty here */
/* Migrate folios selected for demotion */
- nr_reclaimed += demote_folio_list(&demote_folios, pgdat);
+ stat->nr_demoted = demote_folio_list(&demote_folios, pgdat);
+ nr_reclaimed += stat->nr_demoted;
/* Folios that could not be demoted are still in @demote_folios */
if (!list_empty(&demote_folios)) {
/* Folios which weren't demoted go back on @folio_list */
@@ -1984,6 +1982,8 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
spin_lock_irq(&lruvec->lru_lock);
move_folios_to_lru(lruvec, &folio_list);
+ __mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(),
+ stat.nr_demoted);
__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
item = PGSTEAL_KSWAPD + reclaimer_offset();
if (!cgroup_reclaim(sc))
--
2.43.0
