[src/trunk]: src/sys/kern Gather (some) rnd_skew state into a cacheline-align...

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

details:   https://anonhg.NetBSD.org/src/rev/70fe6a92bb39
branches:  trunk
changeset: 337262:70fe6a92bb39
user:      riastradh <riastradh%NetBSD.org@localhost>
date:      Wed Apr 08 14:04:47 2015 +0000

description:
Gather (some) rnd_skew state into a cacheline-aligned static struct.

diffstat:

 sys/kern/kern_rndq.c |  62 ++++++++++++++++++++++++++++-----------------------
 1 files changed, 34 insertions(+), 28 deletions(-)

diffs (144 lines):

diff -r 5ce226132c5a -r 70fe6a92bb39 sys/kern/kern_rndq.c
--- a/sys/kern/kern_rndq.c      Wed Apr 08 13:47:06 2015 +0000
+++ b/sys/kern/kern_rndq.c      Wed Apr 08 14:04:47 2015 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_rndq.c,v 1.39 2015/04/08 13:45:01 riastradh Exp $ */
+/*     $NetBSD: kern_rndq.c,v 1.40 2015/04/08 14:04:47 riastradh Exp $ */
 
 /*-
  * Copyright (c) 1997-2013 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.39 2015/04/08 13:45:01 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_rndq.c,v 1.40 2015/04/08 14:04:47 riastradh Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -169,7 +169,6 @@
 krndsource_t rnd_printf_source, rnd_autoconf_source;
 
 void *rnd_process, *rnd_wakeup;
-struct callout skew_callout, skew_stop_callout;
 
 void                   rnd_wakeup_readers(void);
 static inline uint32_t rnd_counter(void);
@@ -432,46 +431,53 @@
 }
 
 #if defined(__HAVE_CPU_COUNTER)
-kmutex_t                        rnd_skew_mtx;
+static struct {
+       kmutex_t        lock;
+       struct callout  callout;
+       struct callout  stop_callout;
+} rnd_skew __cacheline_aligned;
 
-static void rnd_skew(void *);
+static void rnd_skew_intr(void *);
 
 static void
 rnd_skew_enable(krndsource_t *rs, bool enabled)
 {
-       mutex_spin_enter(&rnd_skew_mtx);
+
+       mutex_spin_enter(&rnd_skew.lock);
        if (enabled) {
-               rnd_skew(rs);
+               rnd_skew_intr(rs);
        } else {
-               callout_stop(&skew_callout);
+               callout_stop(&rnd_skew.callout);
        }
-       mutex_spin_exit(&rnd_skew_mtx);
+       mutex_spin_exit(&rnd_skew.lock);
 }
 
 static void
-rnd_skew_stop(void *arg)
+rnd_skew_stop_intr(void *arg)
 {
-       mutex_spin_enter(&rnd_skew_mtx);
-       callout_stop(&skew_callout);
-       mutex_spin_exit(&rnd_skew_mtx);
+
+       mutex_spin_enter(&rnd_skew.lock);
+       callout_stop(&rnd_skew.callout);
+       mutex_spin_exit(&rnd_skew.lock);
 }
 
 static void
 rnd_skew_get(size_t bytes, void *priv)
 {
        krndsource_t *skewsrcp = priv;
+
        if (RND_ENABLED(skewsrcp)) {
                /* Measure for 30s */
-               if (mutex_tryenter(&rnd_skew_mtx)) {
-                       callout_schedule(&skew_stop_callout, hz * 30);
-                       callout_schedule(&skew_callout, 1);
-                       mutex_spin_exit(&rnd_skew_mtx);
+               if (mutex_tryenter(&rnd_skew.lock)) {
+                       callout_schedule(&rnd_skew.stop_callout, hz * 30);
+                       callout_schedule(&rnd_skew.callout, 1);
+                       mutex_spin_exit(&rnd_skew.lock);
                }
        }
 }
 
 static void
-rnd_skew(void *arg)
+rnd_skew_intr(void *arg)
 {
        static krndsource_t skewsrc;
        static int live, flipflop;
@@ -484,7 +490,7 @@
         */
        if (__predict_false(!live)) {
                /* XXX must be spin, taken with rndpool_mtx held */
-               mutex_init(&rnd_skew_mtx, MUTEX_DEFAULT, IPL_VM);
+               mutex_init(&rnd_skew.lock, MUTEX_DEFAULT, IPL_VM);
                rndsource_setcb(&skewsrc, rnd_skew_get, &skewsrc);
                rndsource_setenable(&skewsrc, rnd_skew_enable);
                rnd_attach_source(&skewsrc, "callout", RND_TYPE_SKEW,
@@ -494,18 +500,18 @@
                live = 1;
                return;
        }
-       mutex_spin_enter(&rnd_skew_mtx);
+       mutex_spin_enter(&rnd_skew.lock);
        flipflop = !flipflop;
 
        if (RND_ENABLED(&skewsrc)) {
                if (flipflop) {
                        rnd_add_uint32(&skewsrc, rnd_counter());
-                       callout_schedule(&skew_callout, hz / 10);
+                       callout_schedule(&rnd_skew.callout, hz / 10);
                } else {
-                       callout_schedule(&skew_callout, 1);
+                       callout_schedule(&rnd_skew.callout, 1);
                }
        }
-       mutex_spin_exit(&rnd_skew_mtx);
+       mutex_spin_exit(&rnd_skew.lock);
 }
 #endif
 
@@ -571,11 +577,11 @@
         *
         */
 #if defined(__HAVE_CPU_COUNTER)
-       callout_init(&skew_callout, CALLOUT_MPSAFE);
-       callout_init(&skew_stop_callout, CALLOUT_MPSAFE);
-       callout_setfunc(&skew_callout, rnd_skew, NULL);
-       callout_setfunc(&skew_stop_callout, rnd_skew_stop, NULL);
-       rnd_skew(NULL);
+       callout_init(&rnd_skew.callout, CALLOUT_MPSAFE);
+       callout_init(&rnd_skew.stop_callout, CALLOUT_MPSAFE);
+       callout_setfunc(&rnd_skew.callout, rnd_skew_intr, NULL);
+       callout_setfunc(&rnd_skew.stop_callout, rnd_skew_stop_intr, NULL);
+       rnd_skew_intr(NULL);
 #endif
 
        rnd_printf_verbose("rnd: initialised (%u)%s", RND_POOLBITS,