Hi,

in netstat -m output, there are three counters that have been unused since 
2002:

0 requests for memory denied
0 requests for memory delayed
0 calls to protocol drain routines

This is confusing and one may think no out of memory situation occurred 
even if there actually was an mbuf shortage.

I propose to use the first of these counters to count m_pool_alloc() 
failures. This is the sum of the fail counters of the mbufpl and mcl* 
pools, but having this information available in netstat -m makes debugging 
easier. I would also delete the other two counters.

Diff below. Does one need to do something special when changing the sysctl 
structs? Comments, opinions?

Cheers,
Stefan


diff --git a/sys/kern/kern_sysctl.c b/sys/kern/kern_sysctl.c
index bf2a03ce683..088e30367cf 100644
--- a/sys/kern/kern_sysctl.c
+++ b/sys/kern/kern_sysctl.c
@@ -566,8 +566,6 @@ kern_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp, void *newp,
 			mbs.m_mtypes[i] = counters[i];
 
 		mbs.m_drops = counters[MBSTAT_DROPS];
-		mbs.m_wait = counters[MBSTAT_WAIT];
-		mbs.m_drain = counters[MBSTAT_DRAIN];
 		mbs.m_defrag_alloc = counters[MBSTAT_DEFRAG_ALLOC];
 		mbs.m_prepend_alloc = counters[MBSTAT_PREPEND_ALLOC];
 		mbs.m_pullup_alloc = counters[MBSTAT_PULLUP_ALLOC];
diff --git a/sys/kern/uipc_mbuf.c b/sys/kern/uipc_mbuf.c
index b962a4047f5..4f77f9d5906 100644
--- a/sys/kern/uipc_mbuf.c
+++ b/sys/kern/uipc_mbuf.c
@@ -1467,6 +1467,7 @@ m_pool_alloc(struct pool *pp, int flags, int *slowdown)
 		return (v);
 
  fail:
+	counters_inc(mbstat, MBSTAT_DROPS);
 	atomic_sub_long(&mbuf_mem_alloc, pp->pr_pgsize);
 	return (NULL);
 }
diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 12afaeb398e..b39c0c5ac3f 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -363,15 +363,13 @@ u_int mextfree_register(void (*)(caddr_t, u_int, void *));
 
 #define MBSTAT_TYPES		MT_NTYPES
 #define MBSTAT_DROPS		(MBSTAT_TYPES + 0)
-#define MBSTAT_WAIT		(MBSTAT_TYPES + 1)
-#define MBSTAT_DRAIN		(MBSTAT_TYPES + 2)
-#define MBSTAT_DEFRAG_ALLOC	(MBSTAT_TYPES + 3)
-#define MBSTAT_PREPEND_ALLOC	(MBSTAT_TYPES + 4)
-#define MBSTAT_PULLUP_ALLOC	(MBSTAT_TYPES + 5)
-#define MBSTAT_PULLUP_COPY	(MBSTAT_TYPES + 6)
-#define MBSTAT_PULLDOWN_ALLOC	(MBSTAT_TYPES + 7)
-#define MBSTAT_PULLDOWN_COPY	(MBSTAT_TYPES + 8)
-#define MBSTAT_COUNT		(MBSTAT_TYPES + 9)
+#define MBSTAT_DEFRAG_ALLOC	(MBSTAT_TYPES + 1)
+#define MBSTAT_PREPEND_ALLOC	(MBSTAT_TYPES + 2)
+#define MBSTAT_PULLUP_ALLOC	(MBSTAT_TYPES + 3)
+#define MBSTAT_PULLUP_COPY	(MBSTAT_TYPES + 4)
+#define MBSTAT_PULLDOWN_ALLOC	(MBSTAT_TYPES + 5)
+#define MBSTAT_PULLDOWN_COPY	(MBSTAT_TYPES + 6)
+#define MBSTAT_COUNT		(MBSTAT_TYPES + 7)
 
 /*
  * Mbuf statistics.
@@ -380,8 +378,6 @@ u_int mextfree_register(void (*)(caddr_t, u_int, void *));
  */
 struct mbstat {
 	u_long	m_drops;	/* times failed to find space */
-	u_long	m_wait;		/* times waited for space */
-	u_long	m_drain;	/* times drained protocols for space */
 	u_long	m_mtypes[MBSTAT_TYPES];
 				/* type specific mbuf allocations */
 	u_long	m_defrag_alloc;
diff --git a/usr.bin/netstat/mbuf.c b/usr.bin/netstat/mbuf.c
index 7660f832630..8663183d975 100644
--- a/usr.bin/netstat/mbuf.c
+++ b/usr.bin/netstat/mbuf.c
@@ -203,8 +203,6 @@ mbpr(void)
 	    "(current/peak/max)\n", totmem / 1024, totpeak / 1024,
 	    ((unsigned long)maxclusters * MCLBYTES) / 1024);
 	printf("%lu requests for memory denied\n", mbstat.m_drops);
-	printf("%lu requests for memory delayed\n", mbstat.m_wait);
-	printf("%lu calls to protocol drain routines\n", mbstat.m_drain);
 	printf("%lu defrag mbuf allocation\n", mbstat.m_defrag_alloc);
 	printf("%lu prepend mbuf allocation\n", mbstat.m_prepend_alloc);
 	printf("%lu pullup mbuf allocation\n", mbstat.m_pullup_alloc);