[src/trunk]: src/sys/dev Introduce a new flag LB_DTRACE for dtrace lockstat e...

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/9b14354439ae
branches:  trunk
changeset: 336662:9b14354439ae
user:      christos <christos%NetBSD.org@localhost>
date:      Mon Mar 09 01:41:41 2015 +0000

description:
Introduce a new flag LB_DTRACE for dtrace lockstat events.
Split lockstat_enabled into two parts, one controlled by dtrace called
"lockstat_dtrace_enabled" and one by the lockstat device called
"lockstat_dev_enabled". Create a macro that needs to be called when either
of them changes LOCKSTAT_ENABLED_UPDATE().

diffstat:

 sys/dev/lockstat.c |  34 ++++++++++++++++++----------------
 sys/dev/lockstat.h |  14 +++++++++++++-
 2 files changed, 31 insertions(+), 17 deletions(-)

diffs (193 lines):

diff -r 3a9d9d9bddb2 -r 9b14354439ae sys/dev/lockstat.c
--- a/sys/dev/lockstat.c        Mon Mar 09 01:29:40 2015 +0000
+++ b/sys/dev/lockstat.c        Mon Mar 09 01:41:41 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lockstat.c,v 1.20 2015/03/08 22:45:16 christos Exp $   */
+/*     $NetBSD: lockstat.c,v 1.21 2015/03/09 01:41:41 christos Exp $   */
 
 /*-
  * Copyright (c) 2006, 2007 The NetBSD Foundation, Inc.
@@ -40,7 +40,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: lockstat.c,v 1.20 2015/03/08 22:45:16 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: lockstat.c,v 1.21 2015/03/09 01:41:41 christos Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -97,6 +97,7 @@
 dev_type_ioctl(lockstat_ioctl);
 
 volatile u_int lockstat_enabled;
+volatile u_int lockstat_dev_enabled;
 uintptr_t      lockstat_csstart;
 uintptr_t      lockstat_csend;
 uintptr_t      lockstat_csmask;
@@ -111,6 +112,7 @@
 struct timespec        lockstat_stime;
 
 #ifdef KDTRACE_HOOKS
+volatile u_int lockstat_dtrace_enabled;
 CTASSERT(LB_NEVENT <= 3);
 CTASSERT(LB_NLOCK <= (7 << LB_LOCK_SHIFT));
 void
@@ -164,7 +166,7 @@
        lscpu_t *lc;
        lsbuf_t *lb;
 
-       KASSERT(!lockstat_enabled);
+       KASSERT(!lockstat_dev_enabled);
 
        for (CPU_INFO_FOREACH(cii, ci)) {
                if (ci->ci_lockstat != NULL) {
@@ -209,7 +211,7 @@
 lockstat_start(lsenable_t *le)
 {
 
-       KASSERT(!lockstat_enabled);
+       KASSERT(!lockstat_dev_enabled);
 
        lockstat_init_tables(le);
 
@@ -230,8 +232,8 @@
        lockstat_lockend = le->le_lockend;
        membar_sync();
        getnanotime(&lockstat_stime);
-       lockstat_enabled = le->le_mask;
-       membar_producer();
+       lockstat_dev_enabled = le->le_mask;
+       LOCKSTAT_ENABLED_UPDATE();
 }
 
 /*
@@ -247,14 +249,14 @@
        int error;
        lwp_t *l;
 
-       KASSERT(lockstat_enabled);
+       KASSERT(lockstat_dev_enabled);
 
        /*
         * Set enabled false, force a write barrier, and wait for other CPUs
         * to exit lockstat_event().
         */
-       lockstat_enabled = 0;
-       membar_producer();
+       lockstat_dev_enabled = 0;
+       LOCKSTAT_ENABLED_UPDATE();
        getnanotime(&ts);
        tsleep(&lockstat_stop, PPAUSE, "lockstat", mstohz(10));
 
@@ -313,7 +315,7 @@
        lsbuf_t *lb;
        size_t sz;
 
-       KASSERT(!lockstat_enabled);
+       KASSERT(!lockstat_dev_enabled);
        lockstat_free();
 
        sz = sizeof(*lb) * le->le_nbufs;
@@ -322,7 +324,7 @@
        if (lb == NULL)
                return (ENOMEM);
 
-       KASSERT(!lockstat_enabled);
+       KASSERT(!lockstat_dev_enabled);
        KASSERT(lockstat_baseb == NULL);
        lockstat_sizeb = sz;
        lockstat_baseb = lb;
@@ -337,7 +339,7 @@
 lockstat_free(void)
 {
 
-       KASSERT(!lockstat_enabled);
+       KASSERT(!lockstat_dev_enabled);
 
        if (lockstat_baseb != NULL) {
                kmem_free(lockstat_baseb, lockstat_sizeb);
@@ -366,7 +368,7 @@
                    cycles);
 #endif
 
-       if ((flags & lockstat_enabled) != flags || count == 0)
+       if ((flags & lockstat_dev_enabled) != flags || count == 0)
                return;
        if (lock < lockstat_lockstart || lock > lockstat_lockend)
                return;
@@ -474,7 +476,7 @@
                        error = ENODEV;
                        break;
                }
-               if (lockstat_enabled) {
+               if (lockstat_dev_enabled) {
                        error = EBUSY;
                        break;
                }
@@ -510,7 +512,7 @@
                break;
 
        case IOC_LOCKSTAT_DISABLE:
-               if (!lockstat_enabled)
+               if (!lockstat_dev_enabled)
                        error = EINVAL;
                else
                        error = lockstat_stop((lsdisable_t *)data);
@@ -531,7 +533,7 @@
 lockstat_read(dev_t dev, struct uio *uio, int flag)
 {
 
-       if (curlwp != lockstat_lwp || lockstat_enabled)
+       if (curlwp != lockstat_lwp || lockstat_dev_enabled)
                return EBUSY;
        return uiomove(lockstat_baseb, lockstat_sizeb, uio);
 }
diff -r 3a9d9d9bddb2 -r 9b14354439ae sys/dev/lockstat.h
--- a/sys/dev/lockstat.h        Mon Mar 09 01:29:40 2015 +0000
+++ b/sys/dev/lockstat.h        Mon Mar 09 01:41:41 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: lockstat.h,v 1.12 2015/03/09 00:40:35 christos Exp $   */
+/*     $NetBSD: lockstat.h,v 1.13 2015/03/09 01:41:41 christos Exp $   */
 
 /*-
  * Copyright (c) 2006 The NetBSD Foundation, Inc.
@@ -119,6 +119,8 @@
 #define        LB_LOCK_MASK            0x0000ff00
 #define        LB_LOCK_SHIFT           8
 
+#define        LB_DTRACE               0x00010000
+
 typedef struct lsbuf {
        union {
                LIST_ENTRY(lsbuf) list;
@@ -180,6 +182,7 @@
 void   lockstat_event(uintptr_t, uintptr_t, u_int, u_int, uint64_t);
 
 extern volatile u_int  lockstat_enabled;
+extern volatile u_int  lockstat_dev_enabled;
 
 #else
 
@@ -197,6 +200,8 @@
 #endif
 
 #ifdef KDTRACE_HOOKS
+extern volatile u_int lockstat_dtrace_enabled;
+#define KDTRACE_LOCKSTAT_ENABLED lockstat_dtrace_enabled
 #define LS_COMPRESS(f) \
     ((((f) & 0x3) | (((f) & 0x700) >> 6)) & (LS_NPROBES - 1))
 #define        LS_NPROBES      0x20    /* 5 bits */
@@ -207,6 +212,13 @@
 
 void           lockstat_probe_stub(uint32_t, uintptr_t, uintptr_t,
     uintptr_t, uintptr_t, uintptr_t);
+#else
+#define KDTRACE_LOCKSTAT_ENABLED 0
 #endif
 
+#define LOCKSTAT_ENABLED_UPDATE() do { \
+       lockstat_enabled = lockstat_dev_enabled | KDTRACE_LOCKSTAT_ENABLED; \
+       membar_producer(); \
+    } while (/*CONSTCOND*/0)
+
 #endif /* _SYS_LOCKSTAT_H_ */