[PATCH] slab: add statistics for alien cache overflows
Add a statistics counter which is incremented everytime the alien cache
overflows. alien_cache limit is hardcoded to 12 right now. We can use
this statistics to tune alien cache if needed in the future.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/slab.c b/mm/slab.c
index afabad5..752c557 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -420,6 +420,7 @@
unsigned long max_freeable;
unsigned long node_allocs;
unsigned long node_frees;
+ unsigned long node_overflow;
atomic_t allochit;
atomic_t allocmiss;
atomic_t freehit;
@@ -465,6 +466,7 @@
#define STATS_INC_ERR(x) ((x)->errors++)
#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
#define STATS_INC_NODEFREES(x) ((x)->node_frees++)
+#define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
#define STATS_SET_FREEABLE(x, i) \
do { \
if ((x)->max_freeable < i) \
@@ -484,6 +486,7 @@
#define STATS_INC_ERR(x) do { } while (0)
#define STATS_INC_NODEALLOCS(x) do { } while (0)
#define STATS_INC_NODEFREES(x) do { } while (0)
+#define STATS_INC_ACOVERFLOW(x) do { } while (0)
#define STATS_SET_FREEABLE(x, i) do { } while (0)
#define STATS_INC_ALLOCHIT(x) do { } while (0)
#define STATS_INC_ALLOCMISS(x) do { } while (0)
@@ -3083,9 +3086,11 @@
if (l3->alien && l3->alien[nodeid]) {
alien = l3->alien[nodeid];
spin_lock(&alien->lock);
- if (unlikely(alien->avail == alien->limit))
+ if (unlikely(alien->avail == alien->limit)) {
+ STATS_INC_ACOVERFLOW(cachep);
__drain_alien_cache(cachep,
alien, nodeid);
+ }
alien->entry[alien->avail++] = objp;
spin_unlock(&alien->lock);
} else {
@@ -3763,7 +3768,7 @@
seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
#if STATS
seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
- "<error> <maxfreeable> <nodeallocs> <remotefrees>");
+ "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
#endif
seq_putc(m, '\n');
@@ -3877,11 +3882,12 @@
unsigned long max_freeable = cachep->max_freeable;
unsigned long node_allocs = cachep->node_allocs;
unsigned long node_frees = cachep->node_frees;
+ unsigned long overflows = cachep->node_overflow;
seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
- %4lu %4lu %4lu %4lu", allocs, high, grown,
+ %4lu %4lu %4lu %4lu %4lu", allocs, high, grown,
reaped, errors, max_freeable, node_allocs,
- node_frees);
+ node_frees, overflows);
}
/* cpu stats */
{