mm: vmscan: split proactive reclaim statistics from direct reclaim st…

…atistics Patch series "Adding Proactive Memory Reclaim Statistics". These two patches are related to proactive memory reclaim. Patch 1 Split proactive reclaim statistics from direct reclaim counters and introduces new counters: pgsteal_proactive, pgdemote_proactive, and pgscan_proactive. Patch 2 Adds pswpin and pswpout items to the cgroup-v2 documentation. This patch (of 2): In proactive memory reclaim scenarios, it is necessary to accurately track proactive reclaim statistics to dynamically adjust the frequency and amount of memory being reclaimed proactively. Currently, proactive reclaim is included in direct reclaim statistics, which can make these direct reclaim statistics misleading. Therefore, separate proactive reclaim memory from the direct reclaim counters by introducing new counters: pgsteal_proactive, pgdemote_proactive, and pgscan_proactive, to avoid confusion with direct reclaim. Link: https://lkml.kernel.org/r/20250318075833.90615-1-jiahao.kernel@gmail.com Link: https://lkml.kernel.org/r/20250318075833.90615-2-jiahao.kernel@gmail.com Signed-off-by: Hao Jia <jiahao1@lixiang.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Michal Koutný <mkoutny@suse.com> Cc: Muchun Song <muchun.song@linux.dev> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Shakeel Butt <shakeel.butt@linux.dev> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mariux64 · Mar 22, 2025 · e452872 · e452872
1 parent a2c6f9c
commit e452872
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Showing 6 changed files with 42 additions and 15 deletions.
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
@@ -1576,6 +1576,9 @@ The following nested keys are defined.
 	  pgscan_khugepaged (npn)
 		Amount of scanned pages by khugepaged  (in an inactive LRU list)
 
+	  pgscan_proactive (npn)
+		Amount of scanned pages proactively (in an inactive LRU list)
+
 	  pgsteal_kswapd (npn)
 		Amount of reclaimed pages by kswapd
 
@@ -1585,6 +1588,9 @@ The following nested keys are defined.
 	  pgsteal_khugepaged (npn)
 		Amount of reclaimed pages by khugepaged
 
+	  pgsteal_proactive (npn)
+		Amount of reclaimed pages proactively
+
 	  pgfault (npn)
 		Total number of page faults incurred
 
@@ -1662,6 +1668,9 @@ The following nested keys are defined.
 	  pgdemote_khugepaged
 		Number of pages demoted by khugepaged.
 
+	  pgdemote_proactive
+		Number of pages demoted by proactively.
+
 	  hugetlb
 		Amount of memory used by hugetlb pages. This metric only shows
 		up if hugetlb usage is accounted for in memory.current (i.e.

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
@@ -221,6 +221,7 @@ enum node_stat_item {
 	PGDEMOTE_KSWAPD,
 	PGDEMOTE_DIRECT,
 	PGDEMOTE_KHUGEPAGED,
+	PGDEMOTE_PROACTIVE,
 #ifdef CONFIG_HUGETLB_PAGE
 	NR_HUGETLB,
 #endif

diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
@@ -41,9 +41,11 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
 		PGSTEAL_KSWAPD,
 		PGSTEAL_DIRECT,
 		PGSTEAL_KHUGEPAGED,
+		PGSTEAL_PROACTIVE,
 		PGSCAN_KSWAPD,
 		PGSCAN_DIRECT,
 		PGSCAN_KHUGEPAGED,
+		PGSCAN_PROACTIVE,
 		PGSCAN_DIRECT_THROTTLE,
 		PGSCAN_ANON,
 		PGSCAN_FILE,

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
@@ -315,6 +315,7 @@ static const unsigned int memcg_node_stat_items[] = {
 	PGDEMOTE_KSWAPD,
 	PGDEMOTE_DIRECT,
 	PGDEMOTE_KHUGEPAGED,
+	PGDEMOTE_PROACTIVE,
 #ifdef CONFIG_HUGETLB_PAGE
 	NR_HUGETLB,
 #endif
@@ -431,9 +432,11 @@ static const unsigned int memcg_vm_event_stat[] = {
 	PGSCAN_KSWAPD,
 	PGSCAN_DIRECT,
 	PGSCAN_KHUGEPAGED,
+	PGSCAN_PROACTIVE,
 	PGSTEAL_KSWAPD,
 	PGSTEAL_DIRECT,
 	PGSTEAL_KHUGEPAGED,
+	PGSTEAL_PROACTIVE,
 	PGFAULT,
 	PGMAJFAULT,
 	PGREFILL,
@@ -1394,6 +1397,7 @@ static const struct memory_stat memory_stats[] = {
 	{ "pgdemote_kswapd",		PGDEMOTE_KSWAPD		},
 	{ "pgdemote_direct",		PGDEMOTE_DIRECT		},
 	{ "pgdemote_khugepaged",	PGDEMOTE_KHUGEPAGED	},
+	{ "pgdemote_proactive",		PGDEMOTE_PROACTIVE	},
 #ifdef CONFIG_NUMA_BALANCING
 	{ "pgpromote_success",		PGPROMOTE_SUCCESS	},
 #endif
@@ -1436,6 +1440,7 @@ static int memcg_page_state_output_unit(int item)
 	case PGDEMOTE_KSWAPD:
 	case PGDEMOTE_DIRECT:
 	case PGDEMOTE_KHUGEPAGED:
+	case PGDEMOTE_PROACTIVE:
 #ifdef CONFIG_NUMA_BALANCING
 	case PGPROMOTE_SUCCESS:
 #endif
@@ -1509,10 +1514,12 @@ static void memcg_stat_format(struct mem_cgroup *memcg, struct seq_buf *s)
 	seq_buf_printf(s, "pgscan %lu\n",
 		       memcg_events(memcg, PGSCAN_KSWAPD) +
 		       memcg_events(memcg, PGSCAN_DIRECT) +
+		       memcg_events(memcg, PGSCAN_PROACTIVE) +
 		       memcg_events(memcg, PGSCAN_KHUGEPAGED));
 	seq_buf_printf(s, "pgsteal %lu\n",
 		       memcg_events(memcg, PGSTEAL_KSWAPD) +
 		       memcg_events(memcg, PGSTEAL_DIRECT) +
+		       memcg_events(memcg, PGSTEAL_PROACTIVE) +
 		       memcg_events(memcg, PGSTEAL_KHUGEPAGED));
 
 	for (i = 0; i < ARRAY_SIZE(memcg_vm_event_stat); i++) {

diff --git a/mm/vmscan.c b/mm/vmscan.c
@@ -456,21 +456,26 @@ void drop_slab(void)
 	} while ((freed >> shift++) > 1);
 }
 
-static int reclaimer_offset(void)
+#define CHECK_RECLAIMER_OFFSET(type)					\
+	do {								\
+		BUILD_BUG_ON(PGSTEAL_##type - PGSTEAL_KSWAPD !=		\
+			     PGDEMOTE_##type - PGDEMOTE_KSWAPD);	\
+		BUILD_BUG_ON(PGSTEAL_##type - PGSTEAL_KSWAPD !=		\
+			     PGSCAN_##type - PGSCAN_KSWAPD);		\
+	} while (0)
+
+static int reclaimer_offset(struct scan_control *sc)
 {
-	BUILD_BUG_ON(PGSTEAL_DIRECT - PGSTEAL_KSWAPD !=
-			PGDEMOTE_DIRECT - PGDEMOTE_KSWAPD);
-	BUILD_BUG_ON(PGSTEAL_KHUGEPAGED - PGSTEAL_KSWAPD !=
-			PGDEMOTE_KHUGEPAGED - PGDEMOTE_KSWAPD);
-	BUILD_BUG_ON(PGSTEAL_DIRECT - PGSTEAL_KSWAPD !=
-			PGSCAN_DIRECT - PGSCAN_KSWAPD);
-	BUILD_BUG_ON(PGSTEAL_KHUGEPAGED - PGSTEAL_KSWAPD !=
-			PGSCAN_KHUGEPAGED - PGSCAN_KSWAPD);
+	CHECK_RECLAIMER_OFFSET(DIRECT);
+	CHECK_RECLAIMER_OFFSET(KHUGEPAGED);
+	CHECK_RECLAIMER_OFFSET(PROACTIVE);
 
 	if (current_is_kswapd())
 		return 0;
 	if (current_is_khugepaged())
 		return PGSTEAL_KHUGEPAGED - PGSTEAL_KSWAPD;
+	if (sc->proactive)
+		return PGSTEAL_PROACTIVE - PGSTEAL_KSWAPD;
 	return PGSTEAL_DIRECT - PGSTEAL_KSWAPD;
 }
 
@@ -2008,7 +2013,7 @@ static unsigned long shrink_inactive_list(unsigned long nr_to_scan,
 				     &nr_scanned, sc, lru);
 
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, nr_taken);
-	item = PGSCAN_KSWAPD + reclaimer_offset();
+	item = PGSCAN_KSWAPD + reclaimer_offset(sc);
 	if (!cgroup_reclaim(sc))
 		__count_vm_events(item, nr_scanned);
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned);
@@ -2024,10 +2029,10 @@ 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(),
+	__mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc),
 					stat.nr_demoted);
 	__mod_node_page_state(pgdat, NR_ISOLATED_ANON + file, -nr_taken);
-	item = PGSTEAL_KSWAPD + reclaimer_offset();
+	item = PGSTEAL_KSWAPD + reclaimer_offset(sc);
 	if (!cgroup_reclaim(sc))
 		__count_vm_events(item, nr_reclaimed);
 	__count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed);
@@ -4571,7 +4576,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc,
 			break;
 	}
 
-	item = PGSCAN_KSWAPD + reclaimer_offset();
+	item = PGSCAN_KSWAPD + reclaimer_offset(sc);
 	if (!cgroup_reclaim(sc)) {
 		__count_vm_events(item, isolated);
 		__count_vm_events(PGREFILL, sorted);
@@ -4721,10 +4726,10 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap
 		reset_batch_size(walk);
 	}
 
-	__mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(),
+	__mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(sc),
 					stat.nr_demoted);
 
-	item = PGSTEAL_KSWAPD + reclaimer_offset();
+	item = PGSTEAL_KSWAPD + reclaimer_offset(sc);
 	if (!cgroup_reclaim(sc))
 		__count_vm_events(item, reclaimed);
 	__count_memcg_events(memcg, item, reclaimed);

diff --git a/mm/vmstat.c b/mm/vmstat.c
@@ -1274,6 +1274,7 @@ const char * const vmstat_text[] = {
 	"pgdemote_kswapd",
 	"pgdemote_direct",
 	"pgdemote_khugepaged",
+	"pgdemote_proactive",
 #ifdef CONFIG_HUGETLB_PAGE
 	"nr_hugetlb",
 #endif
@@ -1309,9 +1310,11 @@ const char * const vmstat_text[] = {
 	"pgsteal_kswapd",
 	"pgsteal_direct",
 	"pgsteal_khugepaged",
+	"pgsteal_proactive",
 	"pgscan_kswapd",
 	"pgscan_direct",
 	"pgscan_khugepaged",
+	"pgscan_proactive",
 	"pgscan_direct_throttle",
 	"pgscan_anon",
 	"pgscan_file",