[src/trunk]: src/sys/kern Implement the 'io' provider for DTrace. From riast...

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

details:   https://anonhg.NetBSD.org/src/rev/138f138df59a
branches:  trunk
changeset: 343375:138f138df59a
user:      riz <riz%NetBSD.org@localhost>
date:      Mon Feb 01 05:05:43 2016 +0000

description:
Implement the 'io' provider for DTrace.  From riastradh@, with
fixes from me.

diffstat:

 sys/kern/subr_devsw.c |  14 ++++++++++++--
 sys/kern/vfs_bio.c    |  19 +++++++++++++++++--
 2 files changed, 29 insertions(+), 4 deletions(-)

diffs (122 lines):

diff -r d3ed63e754b5 -r 138f138df59a sys/kern/subr_devsw.c
--- a/sys/kern/subr_devsw.c     Mon Feb 01 02:59:33 2016 +0000
+++ b/sys/kern/subr_devsw.c     Mon Feb 01 05:05:43 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: subr_devsw.c,v 1.33 2014/09/05 05:57:21 matt Exp $     */
+/*     $NetBSD: subr_devsw.c,v 1.34 2016/02/01 05:05:43 riz Exp $      */
 
 /*-
  * Copyright (c) 2001, 2002, 2007, 2008 The NetBSD Foundation, Inc.
@@ -69,7 +69,11 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: subr_devsw.c,v 1.33 2014/09/05 05:57:21 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: subr_devsw.c,v 1.34 2016/02/01 05:05:43 riz Exp $");
+
+#ifdef _KERNEL_OPT
+#include "opt_dtrace.h"
+#endif
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -80,6 +84,7 @@
 #include <sys/cpu.h>
 #include <sys/buf.h>
 #include <sys/reboot.h>
+#include <sys/sdt.h>
 
 #ifdef DEVSW_DEBUG
 #define        DPRINTF(x)      printf x
@@ -730,12 +735,17 @@
        return rv;
 }
 
+SDT_PROVIDER_DECLARE(io);
+SDT_PROBE_DEFINE1(io, kernel, , start, "struct buf *"/*bp*/);
+
 void
 bdev_strategy(struct buf *bp)
 {
        const struct bdevsw *d;
        int mpflag;
 
+       SDT_PROBE1(io, kernel, , start, bp);
+
        if ((d = bdevsw_lookup(bp->b_dev)) == NULL) {
                bp->b_error = ENXIO;
                bp->b_resid = bp->b_bcount;
diff -r d3ed63e754b5 -r 138f138df59a sys/kern/vfs_bio.c
--- a/sys/kern/vfs_bio.c        Mon Feb 01 02:59:33 2016 +0000
+++ b/sys/kern/vfs_bio.c        Mon Feb 01 05:05:43 2016 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_bio.c,v 1.258 2016/01/11 01:22:36 dholland Exp $   */
+/*     $NetBSD: vfs_bio.c,v 1.259 2016/02/01 05:05:43 riz Exp $        */
 
 /*-
  * Copyright (c) 2007, 2008, 2009 The NetBSD Foundation, Inc.
@@ -123,10 +123,11 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_bio.c,v 1.258 2016/01/11 01:22:36 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_bio.c,v 1.259 2016/02/01 05:05:43 riz Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_bufcache.h"
+#include "opt_dtrace.h"
 #endif
 
 #include <sys/param.h>
@@ -146,6 +147,7 @@
 #include <sys/wapbl.h>
 #include <sys/bitops.h>
 #include <sys/cprng.h>
+#include <sys/sdt.h>
 
 #include <uvm/uvm.h>   /* extern struct uvm uvm */
 
@@ -1474,6 +1476,11 @@
        return size;
 }
 
+SDT_PROVIDER_DEFINE(io);
+
+SDT_PROBE_DEFINE1(io, kernel, , wait__start, "struct buf *"/*bp*/);
+SDT_PROBE_DEFINE1(io, kernel, , wait__done, "struct buf *"/*bp*/);
+
 /*
  * Wait for operations on the buffer to complete.
  * When they do, extract and return the I/O's error value.
@@ -1485,11 +1492,15 @@
        KASSERT(ISSET(bp->b_cflags, BC_BUSY));
        KASSERT(bp->b_refcnt > 0);
 
+       SDT_PROBE1(io, kernel, , wait__start, bp);
+
        mutex_enter(bp->b_objlock);
        while (!ISSET(bp->b_oflags, BO_DONE | BO_DELWRI))
                cv_wait(&bp->b_done, bp->b_objlock);
        mutex_exit(bp->b_objlock);
 
+       SDT_PROBE1(io, kernel, , wait__done, bp);
+
        return bp->b_error;
 }
 
@@ -1528,11 +1539,15 @@
        }
 }
 
+SDT_PROBE_DEFINE1(io, kernel, , done, "struct buf *"/*bp*/);
+
 static void
 biodone2(buf_t *bp)
 {
        void (*callout)(buf_t *);
 
+       SDT_PROBE1(io, kernel, ,done, bp);
+
        mutex_enter(bp->b_objlock);
        /* Note that the transfer is done. */
        if (ISSET(bp->b_oflags, BO_DONE))