add options MPROF_BUFFERS and MPROF_HASH_SIZE that adjust the sizes of

the mutex profiling buffers.  Document them in the man page and in NOTES.
Ensure _HASH_SIZE is larger than _BUFFERS with a cpp error.

3 files changed, 16 insertions, 0 deletions

diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index 60a625c..41e0e9e 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -222,6 +222,10 @@ options 	WITNESS_SKIPSPIN
 # MUTEX_PROFILING - Profiling mutual exclusion locks (mutexes).  See
 # MUTEX_PROFILING(9) for details.
 options 	MUTEX_PROFILING
+# Set the number of buffers and the hash size.  The hash size MUST be larger
+# than the number of buffers.  Hash size should be prime.
+options		MPROF_BUFFERS="1536"
+options		MPROF_HASH_SIZE="1543"
 
 # Profiling for internal hash tables.
 options 	SLEEPQUEUE_PROFILING
diff --git a/sys/conf/options b/sys/conf/options
index b6ff58c..8c16d05 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -108,6 +108,8 @@ MAC_STUB	opt_dontuse.h
 MAC_TEST	opt_dontuse.h
 MD_ROOT		opt_md.h
 MD_ROOT_SIZE	opt_md.h
+MPROF_BUFFERS	opt_mprof.h
+MPROF_HASH_SIZE	opt_mprof.h
 MUTEX_WAKE_ALL
 NSWBUF_MIN	opt_swap.h
 PANIC_REBOOT_WAIT_TIME	opt_panic.h
diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 884eeda..c041886 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
 
 #include "opt_adaptive_mutexes.h"
 #include "opt_ddb.h"
+#include "opt_mprof.h"
 #include "opt_mutex_wake_all.h"
 
 #include <sys/param.h>
@@ -118,10 +119,19 @@ struct mutex_prof {
  *
  * Note: NUM_MPROF_BUFFERS must be smaller than MPROF_HASH_SIZE.
  */
+#ifdef MPROF_BUFFERS
+#define NUM_MPROF_BUFFERS	MPROF_BUFFERS
+#else
 #define	NUM_MPROF_BUFFERS	1000
+#endif
 static struct mutex_prof mprof_buf[NUM_MPROF_BUFFERS];
 static int first_free_mprof_buf;
+#ifndef MPROF_HASH_SIZE
 #define	MPROF_HASH_SIZE		1009
+#endif
+#if NUM_MPROF_BUFFERS >= MPROF_HASH_SIZE
+#error MPROF_BUFFERS must be larger than MPROF_HASH_SIZE
+#endif
 static struct mutex_prof *mprof_hash[MPROF_HASH_SIZE];
 /* SWAG: sbuf size = avg stat. line size * number of locks */
 #define MPROF_SBUF_SIZE		256 * 400