Add a new column to the output of vmstat -z to indicate the number

of times the system was forced to sleep when requesting a new allocation.

Expand the debugger hook, db_show_uma, to display these results as well.

This has proven to be very useful in out of memory situations when
it is not known why systems have become sluggish or fail in odd ways.

Reviewed by:	rwatson alc
Approved by:	scottl (mentor) peter
Obtained from:	Yahoo Inc.

4 files changed, 12 insertions, 0 deletions

diff --git a/lib/libmemstat/memstat.c b/lib/libmemstat/memstat.c
index 28e4813..1a08d3f 100644
--- a/lib/libmemstat/memstat.c
+++ b/lib/libmemstat/memstat.c
@@ -188,6 +188,7 @@ _memstat_mt_reset_stats(struct memory_type *mtp)
 	mtp->mt_count = 0;
 	mtp->mt_free = 0;
 	mtp->mt_failures = 0;
+	mtp->mt_sleeps = 0;
 
 	mtp->mt_zonefree = 0;
 	mtp->mt_kegfree = 0;
@@ -304,6 +305,13 @@ memstat_get_failures(const struct memory_type *mtp)
 	return (mtp->mt_failures);
 }
 
+uint64_t
+memstat_get_sleeps(const struct memory_type *mtp)
+{
+
+	return (mtp->mt_sleeps);
+}
+
 void *
 memstat_get_caller_pointer(const struct memory_type *mtp, int index)
 {
diff --git a/lib/libmemstat/memstat.h b/lib/libmemstat/memstat.h
index aaa85702..e973f1a 100644
--- a/lib/libmemstat/memstat.h
+++ b/lib/libmemstat/memstat.h
@@ -139,6 +139,7 @@ uint64_t	 memstat_get_bytes(const struct memory_type *mtp);
 uint64_t	 memstat_get_count(const struct memory_type *mtp);
 uint64_t	 memstat_get_free(const struct memory_type *mtp);
 uint64_t	 memstat_get_failures(const struct memory_type *mtp);
+uint64_t	 memstat_get_sleeps(const struct memory_type *mtp);
 void		*memstat_get_caller_pointer(const struct memory_type *mtp,
 		    int index);
 void		 memstat_set_caller_pointer(struct memory_type *mtp,
diff --git a/lib/libmemstat/memstat_internal.h b/lib/libmemstat/memstat_internal.h
index 7123518..b7fdd71 100644
--- a/lib/libmemstat/memstat_internal.h
+++ b/lib/libmemstat/memstat_internal.h
@@ -65,6 +65,7 @@ struct memory_type {
 	uint64_t	 mt_count;	/* Number of current allocations. */
 	uint64_t	 mt_free;	/* Number of cached free items. */
 	uint64_t	 mt_failures;	/* Number of allocation failures. */
+	uint64_t	 mt_sleeps;	/* Number of allocation sleeps. */
 
 	/*
 	 * Caller-owned memory.
diff --git a/lib/libmemstat/memstat_uma.c b/lib/libmemstat/memstat_uma.c
index b24721f..4aae61a 100644
--- a/lib/libmemstat/memstat_uma.c
+++ b/lib/libmemstat/memstat_uma.c
@@ -208,6 +208,7 @@ retry:
 		mtp->mt_numallocs = uthp->uth_allocs;
 		mtp->mt_numfrees = uthp->uth_frees;
 		mtp->mt_failures = uthp->uth_fails;
+		mtp->mt_sleeps = uthp->uth_sleeps;
 
 		for (j = 0; j < maxcpus; j++) {
 			upsp = (struct uma_percpu_stat *)p;
@@ -402,6 +403,7 @@ memstat_kvm_uma(struct memory_type_list *list, void *kvm_handle)
 			mtp->mt_numallocs = uz.uz_allocs;
 			mtp->mt_numfrees = uz.uz_frees;
 			mtp->mt_failures = uz.uz_fails;
+			mtp->mt_sleeps = uz.uz_sleeps;
 			if (kz.uk_flags & UMA_ZFLAG_INTERNAL)
 				goto skip_percpu;
 			for (i = 0; i < mp_maxid + 1; i++) {