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authorRoman Gushchin <guro@fb.com>2020-08-07 09:20:35 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2020-08-07 21:33:24 +0300
commitea426c2a7de8e575108b7cecd3374e0c15a9f25e (patch)
treede8856088f287558774c1bc4ad0c9ad4904d8420 /include
parenteedc4e5a142cc33fbb54f8d72b929a0e123c48c4 (diff)
downloadlinux-ea426c2a7de8e575108b7cecd3374e0c15a9f25e.tar.xz
mm: memcg: prepare for byte-sized vmstat items
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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Shakeel Butt <shakeelb@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20200623174037.3951353-3-guro@fb.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/mmzone.h10
-rw-r--r--include/linux/vmstat.h14
2 files changed, 23 insertions, 1 deletions
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
@@ -207,6 +207,16 @@ enum node_stat_item {
};
/*
+ * 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
* the array than the corresponding inactive lists, and to keep
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