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Break the slow path for callout_halt() out into its own routine. 

No functional change.
This commit is contained in:
ad 2019-11-21 17:57:40 +00:00
parent bec282a611
commit 298a9247c2
1 changed files with 34 additions and 16 deletions
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50
sys/kern/kern_timeout.c
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@ -1,7 +1,7 @@
/* $NetBSD: kern_timeout.c,v 1.56 2019/03/10 13:44:49 kre Exp $ */
/* $NetBSD: kern_timeout.c,v 1.57 2019/11/21 17:57:40 ad Exp $ */
/*-
* Copyright (c) 2003, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
* Copyright (c) 2003, 2006, 2007, 2008, 2009, 2019 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
@ -59,7 +59,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.56 2019/03/10 13:44:49 kre Exp $");
__KERNEL_RCSID(0, "$NetBSD: kern_timeout.c,v 1.57 2019/11/21 17:57:40 ad Exp $");
/*
* Timeouts are kept in a hierarchical timing wheel. The c_time is the
@ -185,8 +185,10 @@ struct callout_cpu {
#ifndef CRASH
static void callout_softclock(void *);
static struct callout_cpu callout_cpu0;
static void *callout_sih;
static void callout_wait(callout_impl_t *, void *, kmutex_t *);
static struct callout_cpu callout_cpu0 __cacheline_aligned;
static void *callout_sih __read_mostly;
static inline kmutex_t *
callout_lock(callout_impl_t *c)
@ -466,24 +468,42 @@ bool
callout_halt(callout_t *cs, void *interlock)
{
callout_impl_t *c = (callout_impl_t *)cs;
struct callout_cpu *cc;
struct lwp *l;
kmutex_t *lock, *relock;
bool expired;
kmutex_t *lock;
int flags;
KASSERT(c->c_magic == CALLOUT_MAGIC);
KASSERT(!cpu_intr_p());
KASSERT(interlock == NULL || mutex_owned(interlock));
/* Fast path. */
lock = callout_lock(c);
relock = NULL;
expired = ((c->c_flags & CALLOUT_FIRED) != 0);
if ((c->c_flags & CALLOUT_PENDING) != 0)
flags = c->c_flags;
if ((flags & CALLOUT_PENDING) != 0)
CIRCQ_REMOVE(&c->c_list);
c->c_flags &= ~(CALLOUT_PENDING|CALLOUT_FIRED);
c->c_flags = flags & ~(CALLOUT_PENDING|CALLOUT_FIRED);
if (__predict_false(flags & CALLOUT_FIRED)) {
callout_wait(c, interlock, lock);
return true;
}
mutex_spin_exit(lock);
return false;
}
/*
* callout_wait:
*
* Slow path for callout_halt(). Deliberately marked __noinline to
* prevent unneeded overhead in the caller.
*/
static void __noinline
callout_wait(callout_impl_t *c, void *interlock, kmutex_t *lock)
{
struct callout_cpu *cc;
struct lwp *l;
kmutex_t *relock;
l = curlwp;
relock = NULL;
for (;;) {
cc = c->c_cpu;
if (__predict_true(cc->cc_active != c || cc->cc_lwp == l))
@ -515,8 +535,6 @@ callout_halt(callout_t *cs, void *interlock)
mutex_spin_exit(lock);
if (__predict_false(relock != NULL))
mutex_enter(relock);
return expired;
}
#ifdef notyet