0,0 → 1,192 |
/* |
* Copyright (C) 2001-2004 Jakub Jermar |
* All rights reserved. |
* |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* are met: |
* |
* - Redistributions of source code must retain the above copyright |
* notice, this list of conditions and the following disclaimer. |
* - Redistributions in binary form must reproduce the above copyright |
* notice, this list of conditions and the following disclaimer in the |
* documentation and/or other materials provided with the distribution. |
* - The name of the author may not be used to endorse or promote products |
* derived from this software without specific prior written permission. |
* |
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
*/ |
|
/** @addtogroup time |
* @{ |
*/ |
|
/** |
* @file |
* @brief High-level clock interrupt handler. |
* |
* This file contains the clock() function which is the source |
* of preemption. It is also responsible for executing expired |
* timeouts. |
*/ |
|
#include <time/clock.h> |
#include <time/timeout.h> |
#include <arch/types.h> |
#include <config.h> |
#include <synch/spinlock.h> |
#include <synch/waitq.h> |
#include <func.h> |
#include <proc/scheduler.h> |
#include <cpu.h> |
#include <arch.h> |
#include <adt/list.h> |
#include <atomic.h> |
#include <proc/thread.h> |
#include <sysinfo/sysinfo.h> |
#include <arch/barrier.h> |
|
/* Pointers to public variables with time */ |
struct ptime { |
__native seconds1; |
__native useconds; |
__native seconds2; |
}; |
struct ptime *public_time; |
/* Variable holding fragment of second, so that we would update |
* seconds correctly |
*/ |
static __native secfrag = 0; |
|
/** Initialize realtime clock counter |
* |
* The applications (and sometimes kernel) need to access accurate |
* information about realtime data. We allocate 1 page with these |
* data and update it periodically. |
* |
* |
*/ |
void clock_counter_init(void) |
{ |
void *faddr; |
|
faddr = (void *)PFN2ADDR(frame_alloc(0, FRAME_ATOMIC)); |
if (!faddr) |
panic("Cannot allocate page for clock"); |
|
public_time = (struct ptime *)PA2KA(faddr); |
|
/* TODO: We would need some arch dependent settings here */ |
public_time->seconds1 = 0; |
public_time->seconds2 = 0; |
public_time->useconds = 0; |
|
sysinfo_set_item_val("clock.faddr", NULL, (__native)faddr); |
} |
|
|
/** Update public counters |
* |
* Update it only on first processor |
* TODO: Do we really need so many write barriers? |
*/ |
static void clock_update_counters(void) |
{ |
if (CPU->id == 0) { |
secfrag += 1000000/HZ; |
if (secfrag >= 1000000) { |
secfrag -= 1000000; |
public_time->seconds1++; |
write_barrier(); |
public_time->useconds = secfrag; |
write_barrier(); |
public_time->seconds2 = public_time->seconds1; |
} else |
public_time->useconds += 1000000/HZ; |
} |
} |
|
/** Clock routine |
* |
* Clock routine executed from clock interrupt handler |
* (assuming interrupts_disable()'d). Runs expired timeouts |
* and preemptive scheduling. |
* |
*/ |
void clock(void) |
{ |
link_t *l; |
timeout_t *h; |
timeout_handler_t f; |
void *arg; |
count_t missed_clock_ticks = CPU->missed_clock_ticks; |
int i; |
|
/* |
* To avoid lock ordering problems, |
* run all expired timeouts as you visit them. |
*/ |
for (i = 0; i <= missed_clock_ticks; i++) { |
clock_update_counters(); |
spinlock_lock(&CPU->timeoutlock); |
while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) { |
h = list_get_instance(l, timeout_t, link); |
spinlock_lock(&h->lock); |
if (h->ticks-- != 0) { |
spinlock_unlock(&h->lock); |
break; |
} |
list_remove(l); |
f = h->handler; |
arg = h->arg; |
timeout_reinitialize(h); |
spinlock_unlock(&h->lock); |
spinlock_unlock(&CPU->timeoutlock); |
|
f(arg); |
|
spinlock_lock(&CPU->timeoutlock); |
} |
spinlock_unlock(&CPU->timeoutlock); |
} |
CPU->missed_clock_ticks = 0; |
|
/* |
* Do CPU usage accounting and find out whether to preempt THREAD. |
*/ |
|
if (THREAD) { |
__u64 ticks; |
|
spinlock_lock(&CPU->lock); |
CPU->needs_relink += 1 + missed_clock_ticks; |
spinlock_unlock(&CPU->lock); |
|
spinlock_lock(&THREAD->lock); |
if ((ticks = THREAD->ticks)) { |
if (ticks >= 1 + missed_clock_ticks) |
THREAD->ticks -= 1 + missed_clock_ticks; |
else |
THREAD->ticks = 0; |
} |
spinlock_unlock(&THREAD->lock); |
|
if (!ticks && !PREEMPTION_DISABLED) { |
scheduler(); |
} |
} |
|
} |
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/** @} |
*/ |
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