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

This commit is contained in:
riastradh 2015-04-08 14:04:47 +00:00
parent f88fc6c6b0
commit 353a30186d
1 changed files with 34 additions and 28 deletions
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62
sys/kern/kern_rndq.c
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@ -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 @@ static krndsource_t rnd_source_anonymous = {
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 @@ rnd_dv_estimate(krndsource_t *rs, uint32_t v)
}
#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 @@ rnd_skew(void *arg)
*/
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 @@ rnd_skew(void *arg)
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 @@ rnd_init(void)
*
*/
#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,