svn commit: r293413 - stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace

[Stanislav Sedov]

Author: stas
Date: Fri Jan  8 03:45:28 2016
New Revision: 293413
URL: https://svnweb.freebsd.org/changeset/base/293413

Log:
  MFC r291545: make the number of fasttrap probes and the size of the trace points hash table
  tunable via sysctl or kernel tunables.

Modified:
  stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c
==============================================================================
--- stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c	Fri Jan  8 03:02:19 2016	(r293412)
+++ stable/10/sys/cddl/contrib/opensolaris/uts/common/dtrace/fasttrap.c	Fri Jan  8 03:45:28 2016	(r293413)
@@ -63,6 +63,8 @@
 #if !defined(sun)
 #include <sys/dtrace_bsd.h>
 #include <sys/eventhandler.h>
+#include <sys/sysctl.h>
+#include <sys/u8_textprep.h>
 #include <sys/user.h>
 #include <vm/vm.h>
 #include <vm/pmap.h>
@@ -172,13 +174,14 @@ static volatile uint64_t fasttrap_mod_ge
 
 /*
  * When the fasttrap provider is loaded, fasttrap_max is set to either
- * FASTTRAP_MAX_DEFAULT or the value for fasttrap-max-probes in the
- * fasttrap.conf file. Each time a probe is created, fasttrap_total is
- * incremented by the number of tracepoints that may be associated with that
- * probe; fasttrap_total is capped at fasttrap_max.
+ * FASTTRAP_MAX_DEFAULT, or the value for fasttrap-max-probes in the
+ * fasttrap.conf file (Illumos), or the value provied in the loader.conf (FreeBSD).
+ * Each time a probe is created, fasttrap_total is incremented by the number
+ * of tracepoints that may be associated with that probe; fasttrap_total is capped
+ * at fasttrap_max.
  */
 #define	FASTTRAP_MAX_DEFAULT		250000
-static uint32_t fasttrap_max;
+static uint32_t fasttrap_max = FASTTRAP_MAX_DEFAULT;
 static uint32_t fasttrap_total;
 
 /*
@@ -226,6 +229,17 @@ static kmutex_t fasttrap_cpuc_pid_lock[M
 static eventhandler_tag fasttrap_thread_dtor_tag;
 #endif
 
+static unsigned long tpoints_hash_size = FASTTRAP_TPOINTS_DEFAULT_SIZE;
+
+#ifdef __FreeBSD__
+SYSCTL_DECL(_kern_dtrace);
+SYSCTL_NODE(_kern_dtrace, OID_AUTO, fasttrap, CTLFLAG_RD, 0, "DTrace fasttrap parameters");
+SYSCTL_UINT(_kern_dtrace_fasttrap, OID_AUTO, max_probes, CTLFLAG_RWTUN, &fasttrap_max,
+    FASTTRAP_MAX_DEFAULT, "Maximum number of fasttrap probes");
+SYSCTL_ULONG(_kern_dtrace_fasttrap, OID_AUTO, tpoints_hash_size, CTLFLAG_RDTUN, &tpoints_hash_size,
+    FASTTRAP_TPOINTS_DEFAULT_SIZE, "Size of the tracepoint hash table");
+#endif
+
 static int
 fasttrap_highbit(ulong_t i)
 {
@@ -2466,8 +2480,6 @@ fasttrap_load(void)
 #if defined(sun)
 	fasttrap_max = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
 	    "fasttrap-max-probes", FASTTRAP_MAX_DEFAULT);
-#else
-	fasttrap_max = FASTTRAP_MAX_DEFAULT;
 #endif
 	fasttrap_total = 0;
 
@@ -2478,12 +2490,14 @@ fasttrap_load(void)
 	nent = ddi_getprop(DDI_DEV_T_ANY, devi, DDI_PROP_DONTPASS,
 	    "fasttrap-hash-size", FASTTRAP_TPOINTS_DEFAULT_SIZE);
 #else
-	nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
+	nent = tpoints_hash_size;
 #endif
 
 	if (nent == 0 || nent > 0x1000000)
 		nent = FASTTRAP_TPOINTS_DEFAULT_SIZE;
 
+	tpoints_hash_size = nent;
+
 	if (ISP2(nent))
 		fasttrap_tpoints.fth_nent = nent;
 	else