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From: Roman Gushchin <guro@fb.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Shakeel Butt <shakeelb@google.com>, <linux-mm@kvack.org>,
	Vlastimil Babka <vbabka@suse.cz>, <kernel-team@fb.com>,
	<linux-kernel@vger.kernel.org>, Roman Gushchin <guro@fb.com>
Subject: [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items
Date: Mon, 22 Jun 2020 18:58:29 -0700	[thread overview]
Message-ID: <20200623015846.1141975-3-guro@fb.com> (raw)
In-Reply-To: <20200623015846.1141975-1-guro@fb.com>

To implement per-object slab memory accounting, we need to convert slab
vmstat counters to bytes.  Actually, out of 4 levels of counters: global,
per-node, per-memcg and per-lruvec only two last levels will require
byte-sized counters.  It's because global and per-node counters will be
counting the number of slab pages, and per-memcg and per-lruvec will be
counting the amount of memory taken by charged slab objects.

Converting all vmstat counters to bytes or even all slab counters to bytes
would introduce an additional overhead.  So instead let's store global and
per-node counters in pages, and memcg and lruvec counters in bytes.

To make the API clean all access helpers (both on the read and write
sides) are dealing with bytes.

To avoid back-and-forth conversions a new flavor of read-side helpers is
introduced, which always returns values in pages: node_page_state_pages()
and global_node_page_state_pages().

Actually new helpers are just reading raw values.  Old helpers are simple
wrappers, which will complain on an attempt to read byte value, because at
the moment no one actually needs bytes.

Thanks to Johannes Weiner for the idea of having the byte-sized API on top
of the page-sized internal storage.

Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
---
 drivers/base/node.c    |  2 +-
 include/linux/mmzone.h | 10 ++++++++++
 include/linux/vmstat.h | 14 +++++++++++++-
 mm/memcontrol.c        | 14 ++++++++++----
 mm/vmstat.c            | 30 ++++++++++++++++++++++++++----
 5 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/drivers/base/node.c b/drivers/base/node.c
index 5b02f69769e8..e21e31359297 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -513,7 +513,7 @@ static ssize_t node_read_vmstat(struct device *dev,
 
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
 		n += sprintf(buf+n, "%s %lu\n", node_stat_name(i),
-			     node_page_state(pgdat, i));
+			     node_page_state_pages(pgdat, i));
 
 	return n;
 }
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f6f884970511..f16306e15b98 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -206,6 +206,16 @@ enum node_stat_item {
 	NR_VM_NODE_STAT_ITEMS
 };
 
+/*
+ * Returns true if the value is measured in bytes (most vmstat values are
+ * measured in pages). This defines the API part, the internal representation
+ * might be different.
+ */
+static __always_inline bool vmstat_item_in_bytes(int idx)
+{
+	return false;
+}
+
 /*
  * We do arithmetic on the LRU lists in various places in the code,
  * so it is important to keep the active lists LRU_ACTIVE higher in
diff --git a/include/linux/vmstat.h b/include/linux/vmstat.h
index aa961088c551..91220ace31da 100644
--- a/include/linux/vmstat.h
+++ b/include/linux/vmstat.h
@@ -8,6 +8,7 @@
 #include <linux/vm_event_item.h>
 #include <linux/atomic.h>
 #include <linux/static_key.h>
+#include <linux/mmdebug.h>
 
 extern int sysctl_stat_interval;
 
@@ -192,7 +193,8 @@ static inline unsigned long global_zone_page_state(enum zone_stat_item item)
 	return x;
 }
 
-static inline unsigned long global_node_page_state(enum node_stat_item item)
+static inline
+unsigned long global_node_page_state_pages(enum node_stat_item item)
 {
 	long x = atomic_long_read(&vm_node_stat[item]);
 #ifdef CONFIG_SMP
@@ -202,6 +204,13 @@ static inline unsigned long global_node_page_state(enum node_stat_item item)
 	return x;
 }
 
+static inline unsigned long global_node_page_state(enum node_stat_item item)
+{
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	return global_node_page_state_pages(item);
+}
+
 static inline unsigned long zone_page_state(struct zone *zone,
 					enum zone_stat_item item)
 {
@@ -242,9 +251,12 @@ extern unsigned long sum_zone_node_page_state(int node,
 extern unsigned long sum_zone_numa_state(int node, enum numa_stat_item item);
 extern unsigned long node_page_state(struct pglist_data *pgdat,
 						enum node_stat_item item);
+extern unsigned long node_page_state_pages(struct pglist_data *pgdat,
+					   enum node_stat_item item);
 #else
 #define sum_zone_node_page_state(node, item) global_zone_page_state(item)
 #define node_page_state(node, item) global_node_page_state(item)
+#define node_page_state_pages(node, item) global_node_page_state_pages(item)
 #endif /* CONFIG_NUMA */
 
 #ifdef CONFIG_SMP
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 13ab84c7e4ac..246f9c70118c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -681,13 +681,16 @@ mem_cgroup_largest_soft_limit_node(struct mem_cgroup_tree_per_node *mctz)
  */
 void __mod_memcg_state(struct mem_cgroup *memcg, int idx, int val)
 {
-	long x;
+	long x, threshold = MEMCG_CHARGE_BATCH;
 
 	if (mem_cgroup_disabled())
 		return;
 
+	if (vmstat_item_in_bytes(idx))
+		threshold <<= PAGE_SHIFT;
+
 	x = val + __this_cpu_read(memcg->vmstats_percpu->stat[idx]);
-	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+	if (unlikely(abs(x) > threshold)) {
 		struct mem_cgroup *mi;
 
 		/*
@@ -718,7 +721,7 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 {
 	struct mem_cgroup_per_node *pn;
 	struct mem_cgroup *memcg;
-	long x;
+	long x, threshold = MEMCG_CHARGE_BATCH;
 
 	pn = container_of(lruvec, struct mem_cgroup_per_node, lruvec);
 	memcg = pn->memcg;
@@ -729,8 +732,11 @@ void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
 	/* Update lruvec */
 	__this_cpu_add(pn->lruvec_stat_local->count[idx], val);
 
+	if (vmstat_item_in_bytes(idx))
+		threshold <<= PAGE_SHIFT;
+
 	x = val + __this_cpu_read(pn->lruvec_stat_cpu->count[idx]);
-	if (unlikely(abs(x) > MEMCG_CHARGE_BATCH)) {
+	if (unlikely(abs(x) > threshold)) {
 		pg_data_t *pgdat = lruvec_pgdat(lruvec);
 		struct mem_cgroup_per_node *pi;
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 3fb23a21f6dd..b171a76bfe83 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -341,6 +341,11 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item,
 	long x;
 	long t;
 
+	if (vmstat_item_in_bytes(item)) {
+		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
+		delta >>= PAGE_SHIFT;
+	}
+
 	x = delta + __this_cpu_read(*p);
 
 	t = __this_cpu_read(pcp->stat_threshold);
@@ -398,6 +403,8 @@ void __inc_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 	s8 v, t;
 
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
 	v = __this_cpu_inc_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v > t)) {
@@ -442,6 +449,8 @@ void __dec_node_state(struct pglist_data *pgdat, enum node_stat_item item)
 	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 	s8 v, t;
 
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
 	v = __this_cpu_dec_return(*p);
 	t = __this_cpu_read(pcp->stat_threshold);
 	if (unlikely(v < - t)) {
@@ -541,6 +550,11 @@ static inline void mod_node_state(struct pglist_data *pgdat,
 	s8 __percpu *p = pcp->vm_node_stat_diff + item;
 	long o, n, t, z;
 
+	if (vmstat_item_in_bytes(item)) {
+		VM_WARN_ON_ONCE(delta & (PAGE_SIZE - 1));
+		delta >>= PAGE_SHIFT;
+	}
+
 	do {
 		z = 0;  /* overflow to node counters */
 
@@ -989,8 +1003,8 @@ unsigned long sum_zone_numa_state(int node,
 /*
  * Determine the per node value of a stat item.
  */
-unsigned long node_page_state(struct pglist_data *pgdat,
-				enum node_stat_item item)
+unsigned long node_page_state_pages(struct pglist_data *pgdat,
+				    enum node_stat_item item)
 {
 	long x = atomic_long_read(&pgdat->vm_stat[item]);
 #ifdef CONFIG_SMP
@@ -999,6 +1013,14 @@ unsigned long node_page_state(struct pglist_data *pgdat,
 #endif
 	return x;
 }
+
+unsigned long node_page_state(struct pglist_data *pgdat,
+			      enum node_stat_item item)
+{
+	VM_WARN_ON_ONCE(vmstat_item_in_bytes(item));
+
+	return node_page_state_pages(pgdat, item);
+}
 #endif
 
 #ifdef CONFIG_COMPACTION
@@ -1577,7 +1599,7 @@ static void zoneinfo_show_print(struct seq_file *m, pg_data_t *pgdat,
 		seq_printf(m, "\n  per-node stats");
 		for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++) {
 			seq_printf(m, "\n      %-12s %lu", node_stat_name(i),
-				   node_page_state(pgdat, i));
+				   node_page_state_pages(pgdat, i));
 		}
 	}
 	seq_printf(m,
@@ -1698,7 +1720,7 @@ static void *vmstat_start(struct seq_file *m, loff_t *pos)
 #endif
 
 	for (i = 0; i < NR_VM_NODE_STAT_ITEMS; i++)
-		v[i] = global_node_page_state(i);
+		v[i] = global_node_page_state_pages(i);
 	v += NR_VM_NODE_STAT_ITEMS;
 
 	global_dirty_limits(v + NR_DIRTY_BG_THRESHOLD,
-- 
2.26.2



  parent reply	other threads:[~2020-06-23  1:59 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-23  1:58 [PATCH v7 00/19] The new cgroup slab memory controller Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 01/19] mm: memcg: factor out memcg- and lruvec-level changes out of __mod_lruvec_state() Roman Gushchin
2020-06-23  1:58 ` Roman Gushchin [this message]
2020-06-23  1:58 ` [PATCH v7 03/19] mm: memcg: convert vmstat slab counters to bytes Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 04/19] mm: slub: implement SLUB version of obj_to_index() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 05/19] mm: memcontrol: decouple reference counting from page accounting Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 06/19] mm: memcg/slab: obj_cgroup API Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 07/19] mm: memcg/slab: allocate obj_cgroups for non-root slab pages Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 08/19] mm: memcg/slab: save obj_cgroup for non-root slab objects Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 09/19] mm: memcg/slab: charge individual slab objects instead of pages Roman Gushchin
2020-06-23  5:19   ` Shakeel Butt
2020-06-23  1:58 ` [PATCH v7 10/19] mm: memcg/slab: deprecate memory.kmem.slabinfo Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 11/19] mm: memcg/slab: move memcg_kmem_bypass() to memcontrol.h Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 12/19] mm: memcg/slab: use a single set of kmem_caches for all accounted allocations Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 13/19] mm: memcg/slab: simplify memcg cache creation Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 14/19] mm: memcg/slab: remove memcg_kmem_get_cache() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 15/19] mm: memcg/slab: deprecate slab_root_caches Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 16/19] mm: memcg/slab: remove redundant check in memcg_accumulate_slabinfo() Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 17/19] mm: memcg/slab: use a single set of kmem_caches for all allocations Roman Gushchin
2020-06-23  5:25   ` Shakeel Butt
2020-06-23  1:58 ` [PATCH v7 18/19] kselftests: cgroup: add kernel memory accounting tests Roman Gushchin
2020-06-23  1:58 ` [PATCH v7 19/19] tools/cgroup: add memcg_slabinfo.py tool Roman Gushchin
2020-06-23 13:53 ` [PATCH v7 00/19] The new cgroup slab memory controller Vlastimil Babka
2020-06-23 15:39   ` Roman Gushchin
2020-06-23 17:40 Roman Gushchin
2020-06-23 17:40 ` [PATCH v7 02/19] mm: memcg: prepare for byte-sized vmstat items Roman Gushchin

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