zsmalloc: always keep per-class stats
Always account per-class `zs_size_stat' stats. This data will help us
make better decisions during compaction. We are especially interested
in OBJ_ALLOCATED and OBJ_USED, which can tell us if class compaction
will result in any memory gain.
For instance, we know the number of allocated objects in the class, the
number of objects being used (so we also know how many objects are not
used) and the number of objects per-page. So we can ensure if we have
enough unused objects to form at least one ZS_EMPTY zspage during
compaction.
We calculate this value on per-class basis so we can calculate a total
number of zspages that can be released. Which is exactly what a
shrinker wants to know.
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 7d816c2..1227f83 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -169,14 +169,12 @@
NR_ZS_STAT_TYPE,
};
-#ifdef CONFIG_ZSMALLOC_STAT
-
-static struct dentry *zs_stat_root;
-
struct zs_size_stat {
unsigned long objs[NR_ZS_STAT_TYPE];
};
+#ifdef CONFIG_ZSMALLOC_STAT
+static struct dentry *zs_stat_root;
#endif
/*
@@ -201,6 +199,8 @@
static const int fullness_threshold_frac = 4;
struct size_class {
+ spinlock_t lock;
+ struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS];
/*
* Size of objects stored in this class. Must be multiple
* of ZS_ALIGN.
@@ -210,16 +210,10 @@
/* Number of PAGE_SIZE sized pages to combine to form a 'zspage' */
int pages_per_zspage;
+ struct zs_size_stat stats;
+
/* huge object: pages_per_zspage == 1 && maxobj_per_zspage == 1 */
bool huge;
-
-#ifdef CONFIG_ZSMALLOC_STAT
- struct zs_size_stat stats;
-#endif
-
- spinlock_t lock;
-
- struct page *fullness_list[_ZS_NR_FULLNESS_GROUPS];
};
/*
@@ -441,8 +435,6 @@
return min(zs_size_classes - 1, idx);
}
-#ifdef CONFIG_ZSMALLOC_STAT
-
static inline void zs_stat_inc(struct size_class *class,
enum zs_stat_type type, unsigned long cnt)
{
@@ -461,6 +453,8 @@
return class->stats.objs[type];
}
+#ifdef CONFIG_ZSMALLOC_STAT
+
static int __init zs_stat_init(void)
{
if (!debugfs_initialized())
@@ -576,23 +570,6 @@
}
#else /* CONFIG_ZSMALLOC_STAT */
-
-static inline void zs_stat_inc(struct size_class *class,
- enum zs_stat_type type, unsigned long cnt)
-{
-}
-
-static inline void zs_stat_dec(struct size_class *class,
- enum zs_stat_type type, unsigned long cnt)
-{
-}
-
-static inline unsigned long zs_stat_get(struct size_class *class,
- enum zs_stat_type type)
-{
- return 0;
-}
-
static int __init zs_stat_init(void)
{
return 0;
@@ -610,7 +587,6 @@
static inline void zs_pool_stat_destroy(struct zs_pool *pool)
{
}
-
#endif