4a027d50c7
for the process, not a separate set for each thread). By default, the process now only has signal handlers installed for SIGVTALRM, SIGINFO and SIGCHLD. The thread kernel signal handler is installed for other signals on demand. This means that SIG_IGN and SIG_DFL processing is now left to the kernel, not the thread kernel. Change the signal dispatch to no longer use a signal thread, and call the signal handler using the stack of the thread that has the signal pending. Change the atomic lock method to use test-and-set asm code with a yield if blocked. This introduces separate locks for each type of object instead of blocking signals to prevent a context switch. It was this blocking of signals that caused the performance degradation the people have noted. This is a *big* change!
1384 lines
35 KiB
C
1384 lines
35 KiB
C
/*
|
|
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. 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.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by John Birrell.
|
|
* 4. Neither the name of the author nor the names of any co-contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
|
|
*
|
|
* $Id: uthread_kern.c,v 1.9 1998/04/17 09:37:41 jb Exp $
|
|
*
|
|
*/
|
|
#include <errno.h>
|
|
#include <stdlib.h>
|
|
#include <stdarg.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <setjmp.h>
|
|
#include <sys/types.h>
|
|
#include <sys/stat.h>
|
|
#include <sys/time.h>
|
|
#include <sys/socket.h>
|
|
#include <sys/uio.h>
|
|
#include <sys/syscall.h>
|
|
#include <fcntl.h>
|
|
#ifdef _THREAD_SAFE
|
|
#include <pthread.h>
|
|
#include "pthread_private.h"
|
|
|
|
/* Static function prototype definitions: */
|
|
static void
|
|
_thread_kern_select(int wait_reqd);
|
|
|
|
void
|
|
_thread_kern_sched(struct sigcontext * scp)
|
|
{
|
|
#ifndef __alpha__
|
|
char *fdata;
|
|
#endif
|
|
int i;
|
|
int prio = -1;
|
|
pthread_t pthread;
|
|
pthread_t pthread_h = NULL;
|
|
pthread_t pthread_nxt = NULL;
|
|
pthread_t pthread_prv = NULL;
|
|
pthread_t pthread_s = NULL;
|
|
struct itimerval itimer;
|
|
struct timespec ts;
|
|
struct timespec ts1;
|
|
struct timeval tv;
|
|
struct timeval tv1;
|
|
|
|
/*
|
|
* Flag the pthread kernel as executing scheduler code
|
|
* to avoid a scheduler signal from interrupting this
|
|
* execution and calling the scheduler again.
|
|
*/
|
|
_thread_kern_in_sched = 1;
|
|
|
|
/* Check if this function was called from the signal handler: */
|
|
if (scp != NULL) {
|
|
/*
|
|
* Copy the signal context to the current thread's jump
|
|
* buffer:
|
|
*/
|
|
memcpy(&_thread_run->saved_sigcontext, scp, sizeof(_thread_run->saved_sigcontext));
|
|
|
|
#ifndef __alpha__
|
|
/* Point to the floating point data in the running thread: */
|
|
fdata = _thread_run->saved_fp;
|
|
|
|
/* Save the floating point data: */
|
|
__asm__("fnsave %0": :"m"(*fdata));
|
|
#endif
|
|
|
|
/* Flag the signal context as the last state saved: */
|
|
_thread_run->sig_saved = 1;
|
|
}
|
|
/* Save the state of the current thread: */
|
|
else if (setjmp(_thread_run->saved_jmp_buf) != 0) {
|
|
/*
|
|
* This point is reached when a longjmp() is called to
|
|
* restore the state of a thread.
|
|
*
|
|
* This is the normal way out of the scheduler.
|
|
*/
|
|
_thread_kern_in_sched = 0;
|
|
|
|
/*
|
|
* There might be pending signals for this thread, so
|
|
* dispatch any that aren't blocked:
|
|
*/
|
|
_dispatch_signals();
|
|
return;
|
|
} else {
|
|
/* Flag the jump buffer was the last state saved: */
|
|
_thread_run->sig_saved = 0;
|
|
}
|
|
|
|
/* Point to the first dead thread (if there are any): */
|
|
pthread = _thread_dead;
|
|
|
|
/* There is no previous dead thread: */
|
|
pthread_prv = NULL;
|
|
|
|
/* Enter a loop to cleanup after dead threads: */
|
|
while (pthread != NULL) {
|
|
/* Save a pointer to the next thread: */
|
|
pthread_nxt = pthread->nxt;
|
|
|
|
/* Check if this thread is one which is running: */
|
|
if (pthread == _thread_run || pthread == _thread_initial) {
|
|
/*
|
|
* Don't destroy the running thread or the initial
|
|
* thread.
|
|
*/
|
|
pthread_prv = pthread;
|
|
}
|
|
/*
|
|
* Check if this thread has detached:
|
|
*/
|
|
else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
|
|
/* Check if there is no previous dead thread: */
|
|
if (pthread_prv == NULL) {
|
|
/*
|
|
* The dead thread is at the head of the
|
|
* list:
|
|
*/
|
|
_thread_dead = pthread_nxt;
|
|
} else {
|
|
/*
|
|
* The dead thread is not at the head of the
|
|
* list:
|
|
*/
|
|
pthread_prv->nxt = pthread->nxt;
|
|
}
|
|
|
|
/*
|
|
* Check if the stack was not specified by the caller
|
|
* to pthread_create and has not been destroyed yet:
|
|
*/
|
|
if (pthread->attr.stackaddr_attr == NULL && pthread->stack != NULL) {
|
|
/* Free the stack of the dead thread: */
|
|
free(pthread->stack);
|
|
}
|
|
/* Free the memory allocated to the thread structure: */
|
|
free(pthread);
|
|
} else {
|
|
/*
|
|
* This thread has not detached, so do not destroy
|
|
* it:
|
|
*/
|
|
pthread_prv = pthread;
|
|
|
|
/*
|
|
* Check if the stack was not specified by the caller
|
|
* to pthread_create and has not been destroyed yet:
|
|
*/
|
|
if (pthread->attr.stackaddr_attr == NULL && pthread->stack != NULL) {
|
|
/* Free the stack of the dead thread: */
|
|
free(pthread->stack);
|
|
|
|
/*
|
|
* NULL the stack pointer now that the memory
|
|
* has been freed:
|
|
*/
|
|
pthread->stack = NULL;
|
|
}
|
|
}
|
|
|
|
/* Point to the next thread: */
|
|
pthread = pthread_nxt;
|
|
}
|
|
|
|
/*
|
|
* Enter a the scheduling loop that finds the next thread that is
|
|
* ready to run. This loop completes when there are no more threads
|
|
* in the global list or when a thread has its state restored by
|
|
* either a sigreturn (if the state was saved as a sigcontext) or a
|
|
* longjmp (if the state was saved by a setjmp).
|
|
*/
|
|
while (_thread_link_list != NULL) {
|
|
/* Get the current time of day: */
|
|
gettimeofday(&tv, NULL);
|
|
TIMEVAL_TO_TIMESPEC(&tv, &ts);
|
|
|
|
/*
|
|
* Poll file descriptors to update the state of threads
|
|
* waiting on file I/O where data may be available:
|
|
*/
|
|
_thread_kern_select(0);
|
|
|
|
/*
|
|
* Enter a loop to look for sleeping threads that are ready:
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL;
|
|
pthread = pthread->nxt) {
|
|
/* Check if this thread is to timeout: */
|
|
if (pthread->state == PS_COND_WAIT ||
|
|
pthread->state == PS_SLEEP_WAIT ||
|
|
pthread->state == PS_FDR_WAIT ||
|
|
pthread->state == PS_FDW_WAIT ||
|
|
pthread->state == PS_SELECT_WAIT) {
|
|
/* Check if this thread is to wait forever: */
|
|
if (pthread->wakeup_time.tv_sec == -1) {
|
|
}
|
|
/*
|
|
* Check if this thread is to wakeup
|
|
* immediately or if it is past its wakeup
|
|
* time:
|
|
*/
|
|
else if ((pthread->wakeup_time.tv_sec == 0 &&
|
|
pthread->wakeup_time.tv_nsec == 0) ||
|
|
(ts.tv_sec > pthread->wakeup_time.tv_sec) ||
|
|
((ts.tv_sec == pthread->wakeup_time.tv_sec) &&
|
|
(ts.tv_nsec >= pthread->wakeup_time.tv_nsec))) {
|
|
/*
|
|
* Check if this thread is waiting on
|
|
* select:
|
|
*/
|
|
if (pthread->state == PS_SELECT_WAIT) {
|
|
/*
|
|
* The select has timed out,
|
|
* so zero the file
|
|
* descriptor sets:
|
|
*/
|
|
FD_ZERO(&pthread->data.select_data->readfds);
|
|
FD_ZERO(&pthread->data.select_data->writefds);
|
|
FD_ZERO(&pthread->data.select_data->exceptfds);
|
|
pthread->data.select_data->nfds = 0;
|
|
}
|
|
/*
|
|
* Return an error as an interrupted
|
|
* wait:
|
|
*/
|
|
_thread_seterrno(pthread, EINTR);
|
|
|
|
/*
|
|
* Flag the timeout in the thread
|
|
* structure:
|
|
*/
|
|
pthread->timeout = 1;
|
|
|
|
/*
|
|
* Change the threads state to allow
|
|
* it to be restarted:
|
|
*/
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Check if there is a current thread: */
|
|
if (_thread_run != &_thread_kern_thread) {
|
|
/*
|
|
* Save the current time as the time that the thread
|
|
* became inactive:
|
|
*/
|
|
_thread_run->last_inactive.tv_sec = tv.tv_sec;
|
|
_thread_run->last_inactive.tv_usec = tv.tv_usec;
|
|
|
|
/*
|
|
* Accumulate the number of microseconds that this
|
|
* thread has run for:
|
|
*/
|
|
_thread_run->slice_usec += (_thread_run->last_inactive.tv_sec -
|
|
_thread_run->last_active.tv_sec) * 1000000 +
|
|
_thread_run->last_inactive.tv_usec -
|
|
_thread_run->last_active.tv_usec;
|
|
|
|
/*
|
|
* Check if this thread has reached its allocated
|
|
* time slice period:
|
|
*/
|
|
if (_thread_run->slice_usec > TIMESLICE_USEC) {
|
|
/*
|
|
* Flag the allocated time slice period as
|
|
* up:
|
|
*/
|
|
_thread_run->slice_usec = -1;
|
|
}
|
|
}
|
|
/* Check if an incremental priority update is required: */
|
|
if (((tv.tv_sec - kern_inc_prio_time.tv_sec) * 1000000 +
|
|
tv.tv_usec - kern_inc_prio_time.tv_usec) > INC_PRIO_USEC) {
|
|
/*
|
|
* Enter a loop to look for run-enabled threads that
|
|
* have not run since the last time that an
|
|
* incremental priority update was performed:
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/* Check if this thread is unable to run: */
|
|
if (pthread->state != PS_RUNNING) {
|
|
}
|
|
/*
|
|
* Check if the last time that this thread
|
|
* was run (as indicated by the last time it
|
|
* became inactive) is before the time that
|
|
* the last incremental priority check was
|
|
* made:
|
|
*/
|
|
else if (timercmp(&_thread_run->last_inactive, &kern_inc_prio_time, >)) {
|
|
/*
|
|
* Increment the incremental priority
|
|
* for this thread in the hope that
|
|
* it will eventually get a chance to
|
|
* run:
|
|
*/
|
|
(pthread->inc_prio)++;
|
|
}
|
|
}
|
|
|
|
/* Save the new incremental priority update time: */
|
|
kern_inc_prio_time.tv_sec = tv.tv_sec;
|
|
kern_inc_prio_time.tv_usec = tv.tv_usec;
|
|
}
|
|
/*
|
|
* Enter a loop to look for the first thread of the highest
|
|
* priority that is ready to run:
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/* Check if the current thread is unable to run: */
|
|
if (pthread->state != PS_RUNNING) {
|
|
}
|
|
/*
|
|
* Check if no run-enabled thread has been seen or if
|
|
* the current thread has a priority higher than the
|
|
* highest seen so far:
|
|
*/
|
|
else if (pthread_h == NULL || (pthread->pthread_priority + pthread->inc_prio) > prio) {
|
|
/*
|
|
* Save this thread as the highest priority
|
|
* thread seen so far:
|
|
*/
|
|
pthread_h = pthread;
|
|
prio = pthread->pthread_priority + pthread->inc_prio;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Enter a loop to look for a thread that: 1. Is run-enabled.
|
|
* 2. Has the required agregate priority. 3. Has not been
|
|
* allocated its allocated time slice. 4. Became inactive
|
|
* least recently.
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/* Check if the current thread is unable to run: */
|
|
if (pthread->state != PS_RUNNING) {
|
|
/* Ignore threads that are not ready to run. */
|
|
}
|
|
|
|
/*
|
|
* Check if the current thread as an agregate
|
|
* priority not equal to the highest priority found
|
|
* above:
|
|
*/
|
|
else if ((pthread->pthread_priority + pthread->inc_prio) != prio) {
|
|
/*
|
|
* Ignore threads which have lower agregate
|
|
* priority.
|
|
*/
|
|
}
|
|
|
|
/*
|
|
* Check if the current thread reached its time slice
|
|
* allocation last time it ran (or if it has not run
|
|
* yet):
|
|
*/
|
|
else if (pthread->slice_usec == -1) {
|
|
}
|
|
|
|
/*
|
|
* Check if an eligible thread has not been found
|
|
* yet, or if the current thread has an inactive time
|
|
* earlier than the last one seen:
|
|
*/
|
|
else if (pthread_s == NULL || timercmp(&pthread->last_inactive, &tv1, <)) {
|
|
/*
|
|
* Save the pointer to the current thread as
|
|
* the most eligible thread seen so far:
|
|
*/
|
|
pthread_s = pthread;
|
|
|
|
/*
|
|
* Save the time that the selected thread
|
|
* became inactive:
|
|
*/
|
|
tv1.tv_sec = pthread->last_inactive.tv_sec;
|
|
tv1.tv_usec = pthread->last_inactive.tv_usec;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check if no thread was selected according to incomplete
|
|
* time slice allocation:
|
|
*/
|
|
if (pthread_s == NULL) {
|
|
/*
|
|
* Enter a loop to look for any other thread that: 1.
|
|
* Is run-enabled. 2. Has the required agregate
|
|
* priority. 3. Became inactive least recently.
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/*
|
|
* Check if the current thread is unable to
|
|
* run:
|
|
*/
|
|
if (pthread->state != PS_RUNNING) {
|
|
/*
|
|
* Ignore threads that are not ready
|
|
* to run.
|
|
*/
|
|
}
|
|
/*
|
|
* Check if the current thread as an agregate
|
|
* priority not equal to the highest priority
|
|
* found above:
|
|
*/
|
|
else if ((pthread->pthread_priority + pthread->inc_prio) != prio) {
|
|
/*
|
|
* Ignore threads which have lower
|
|
* agregate priority.
|
|
*/
|
|
}
|
|
/*
|
|
* Check if an eligible thread has not been
|
|
* found yet, or if the current thread has an
|
|
* inactive time earlier than the last one
|
|
* seen:
|
|
*/
|
|
else if (pthread_s == NULL || timercmp(&pthread->last_inactive, &tv1, <)) {
|
|
/*
|
|
* Save the pointer to the current
|
|
* thread as the most eligible thread
|
|
* seen so far:
|
|
*/
|
|
pthread_s = pthread;
|
|
|
|
/*
|
|
* Save the time that the selected
|
|
* thread became inactive:
|
|
*/
|
|
tv1.tv_sec = pthread->last_inactive.tv_sec;
|
|
tv1.tv_usec = pthread->last_inactive.tv_usec;
|
|
}
|
|
}
|
|
}
|
|
/* Check if there are no threads ready to run: */
|
|
if (pthread_s == NULL) {
|
|
/*
|
|
* Lock the pthread kernel by changing the pointer to
|
|
* the running thread to point to the global kernel
|
|
* thread structure:
|
|
*/
|
|
_thread_run = &_thread_kern_thread;
|
|
|
|
/*
|
|
* There are no threads ready to run, so wait until
|
|
* something happens that changes this condition:
|
|
*/
|
|
_thread_kern_select(1);
|
|
} else {
|
|
/* Make the selected thread the current thread: */
|
|
_thread_run = pthread_s;
|
|
|
|
/*
|
|
* Save the current time as the time that the thread
|
|
* became active:
|
|
*/
|
|
_thread_run->last_active.tv_sec = tv.tv_sec;
|
|
_thread_run->last_active.tv_usec = tv.tv_usec;
|
|
|
|
/*
|
|
* Check if this thread is running for the first time
|
|
* or running again after using its full time slice
|
|
* allocation:
|
|
*/
|
|
if (_thread_run->slice_usec == -1) {
|
|
/* Reset the accumulated time slice period: */
|
|
_thread_run->slice_usec = 0;
|
|
}
|
|
/*
|
|
* Reset the incremental priority now that this
|
|
* thread has been given the chance to run:
|
|
*/
|
|
_thread_run->inc_prio = 0;
|
|
|
|
/* Check if there is more than one thread: */
|
|
if (_thread_run != _thread_link_list || _thread_run->nxt != NULL) {
|
|
/*
|
|
* Define the maximum time before a SIGVTALRM
|
|
* is required:
|
|
*/
|
|
itimer.it_value.tv_sec = 0;
|
|
itimer.it_value.tv_usec = TIMESLICE_USEC;
|
|
|
|
/*
|
|
* The interval timer is not reloaded when it
|
|
* times out. The interval time needs to be
|
|
* calculated every time.
|
|
*/
|
|
itimer.it_interval.tv_sec = 0;
|
|
itimer.it_interval.tv_usec = 0;
|
|
|
|
/*
|
|
* Enter a loop to look for threads waiting
|
|
* for a time:
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/*
|
|
* Check if this thread is to
|
|
* timeout:
|
|
*/
|
|
if (pthread->state == PS_COND_WAIT ||
|
|
pthread->state == PS_SLEEP_WAIT ||
|
|
pthread->state == PS_FDR_WAIT ||
|
|
pthread->state == PS_FDW_WAIT ||
|
|
pthread->state == PS_SELECT_WAIT) {
|
|
/*
|
|
* Check if this thread is to
|
|
* wait forever:
|
|
*/
|
|
if (pthread->wakeup_time.tv_sec == -1) {
|
|
}
|
|
/*
|
|
* Check if this thread is to
|
|
* wakeup immediately:
|
|
*/
|
|
else if (pthread->wakeup_time.tv_sec == 0 &&
|
|
pthread->wakeup_time.tv_nsec == 0) {
|
|
}
|
|
/*
|
|
* Check if the current time
|
|
* is after the wakeup time:
|
|
*/
|
|
else if ((ts.tv_sec > pthread->wakeup_time.tv_sec) ||
|
|
((ts.tv_sec == pthread->wakeup_time.tv_sec) &&
|
|
(ts.tv_nsec > pthread->wakeup_time.tv_nsec))) {
|
|
} else {
|
|
/*
|
|
* Calculate the time
|
|
* until this thread
|
|
* is ready, allowing
|
|
* for the clock
|
|
* resolution:
|
|
*/
|
|
ts1.tv_sec = pthread->wakeup_time.tv_sec - ts.tv_sec;
|
|
ts1.tv_nsec = pthread->wakeup_time.tv_nsec - ts.tv_nsec +
|
|
CLOCK_RES_NSEC;
|
|
|
|
/*
|
|
* Check for
|
|
* underflow of the
|
|
* nanosecond field:
|
|
*/
|
|
if (ts1.tv_nsec < 0) {
|
|
/*
|
|
* Allow for
|
|
* the
|
|
* underflow
|
|
* of the
|
|
* nanosecond
|
|
* field:
|
|
*/
|
|
ts1.tv_sec--;
|
|
ts1.tv_nsec += 1000000000;
|
|
}
|
|
/*
|
|
* Check for overflow
|
|
* of the nanosecond
|
|
* field:
|
|
*/
|
|
if (ts1.tv_nsec >= 1000000000) {
|
|
/*
|
|
* Allow for
|
|
* the
|
|
* overflow
|
|
* of the
|
|
* nanosecond
|
|
* field:
|
|
*/
|
|
ts1.tv_sec++;
|
|
ts1.tv_nsec -= 1000000000;
|
|
}
|
|
/*
|
|
* Convert the
|
|
* timespec structure
|
|
* to a timeval
|
|
* structure:
|
|
*/
|
|
TIMESPEC_TO_TIMEVAL(&tv, &ts1);
|
|
|
|
/*
|
|
* Check if the
|
|
* thread will be
|
|
* ready sooner than
|
|
* the earliest one
|
|
* found so far:
|
|
*/
|
|
if (timercmp(&tv, &itimer.it_value, <)) {
|
|
/*
|
|
* Update the
|
|
* time
|
|
* value:
|
|
*/
|
|
itimer.it_value.tv_sec = tv.tv_sec;
|
|
itimer.it_value.tv_usec = tv.tv_usec;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Start the interval timer for the
|
|
* calculated time interval:
|
|
*/
|
|
if (setitimer(ITIMER_VIRTUAL, &itimer, NULL) != 0) {
|
|
/*
|
|
* Cannot initialise the timer, so
|
|
* abort this process:
|
|
*/
|
|
PANIC("Cannot set virtual timer");
|
|
}
|
|
}
|
|
/* Check if a signal context was saved: */
|
|
if (_thread_run->sig_saved == 1) {
|
|
#ifndef __alpha__
|
|
/*
|
|
* Point to the floating point data in the
|
|
* running thread:
|
|
*/
|
|
fdata = _thread_run->saved_fp;
|
|
|
|
/* Restore the floating point state: */
|
|
__asm__("frstor %0": :"m"(*fdata));
|
|
#endif
|
|
|
|
/*
|
|
* Do a sigreturn to restart the thread that
|
|
* was interrupted by a signal:
|
|
*/
|
|
_thread_sys_sigreturn(&_thread_run->saved_sigcontext);
|
|
} else
|
|
/*
|
|
* Do a longjmp to restart the thread that
|
|
* was context switched out (by a longjmp to
|
|
* a different thread):
|
|
*/
|
|
longjmp(_thread_run->saved_jmp_buf, 1);
|
|
|
|
/* This point should not be reached. */
|
|
PANIC("Thread has returned from sigreturn or longjmp");
|
|
}
|
|
}
|
|
|
|
/* There are no more threads, so exit this process: */
|
|
exit(0);
|
|
}
|
|
|
|
void
|
|
_thread_kern_sched_state(enum pthread_state state, char *fname, int lineno)
|
|
{
|
|
/* Change the state of the current thread: */
|
|
_thread_run->state = state;
|
|
_thread_run->fname = fname;
|
|
_thread_run->lineno = lineno;
|
|
|
|
/* Schedule the next thread that is ready: */
|
|
_thread_kern_sched(NULL);
|
|
return;
|
|
}
|
|
|
|
static void
|
|
_thread_kern_select(int wait_reqd)
|
|
{
|
|
char bufr[128];
|
|
fd_set fd_set_except;
|
|
fd_set fd_set_read;
|
|
fd_set fd_set_write;
|
|
int count = 0;
|
|
int count_dec;
|
|
int found_one;
|
|
int i;
|
|
int nfds = -1;
|
|
int settimeout;
|
|
pthread_t pthread;
|
|
ssize_t num;
|
|
struct timespec ts;
|
|
struct timespec ts1;
|
|
struct timeval *p_tv;
|
|
struct timeval tv;
|
|
struct timeval tv1;
|
|
|
|
/* Zero the file descriptor sets: */
|
|
FD_ZERO(&fd_set_read);
|
|
FD_ZERO(&fd_set_write);
|
|
FD_ZERO(&fd_set_except);
|
|
|
|
/* Check if the caller wants to wait: */
|
|
if (wait_reqd) {
|
|
/*
|
|
* Add the pthread kernel pipe file descriptor to the read
|
|
* set:
|
|
*/
|
|
FD_SET(_thread_kern_pipe[0], &fd_set_read);
|
|
nfds = _thread_kern_pipe[0];
|
|
|
|
/* Get the current time of day: */
|
|
gettimeofday(&tv, NULL);
|
|
TIMEVAL_TO_TIMESPEC(&tv, &ts);
|
|
}
|
|
/* Initialise the time value structure: */
|
|
tv.tv_sec = 0;
|
|
tv.tv_usec = 0;
|
|
|
|
/*
|
|
* Enter a loop to process threads waiting on either file descriptors
|
|
* or times:
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/* Assume that this state does not time out: */
|
|
settimeout = 0;
|
|
|
|
/* Process according to thread state: */
|
|
switch (pthread->state) {
|
|
/*
|
|
* States which do not depend on file descriptor I/O
|
|
* operations or timeouts:
|
|
*/
|
|
case PS_DEAD:
|
|
case PS_FDLR_WAIT:
|
|
case PS_FDLW_WAIT:
|
|
case PS_FILE_WAIT:
|
|
case PS_JOIN:
|
|
case PS_MUTEX_WAIT:
|
|
case PS_RUNNING:
|
|
case PS_SIGTHREAD:
|
|
case PS_SIGWAIT:
|
|
case PS_STATE_MAX:
|
|
case PS_WAIT_WAIT:
|
|
case PS_SUSPENDED:
|
|
/* Nothing to do here. */
|
|
break;
|
|
|
|
/* File descriptor read wait: */
|
|
case PS_FDR_WAIT:
|
|
/* Add the file descriptor to the read set: */
|
|
FD_SET(pthread->data.fd.fd, &fd_set_read);
|
|
|
|
/*
|
|
* Check if this file descriptor is greater than any
|
|
* of those seen so far:
|
|
*/
|
|
if (pthread->data.fd.fd > nfds) {
|
|
/* Remember this file descriptor: */
|
|
nfds = pthread->data.fd.fd;
|
|
}
|
|
/* Increment the file descriptor count: */
|
|
count++;
|
|
|
|
/* This state can time out: */
|
|
settimeout = 1;
|
|
break;
|
|
|
|
/* File descriptor write wait: */
|
|
case PS_FDW_WAIT:
|
|
/* Add the file descriptor to the write set: */
|
|
FD_SET(pthread->data.fd.fd, &fd_set_write);
|
|
|
|
/*
|
|
* Check if this file descriptor is greater than any
|
|
* of those seen so far:
|
|
*/
|
|
if (pthread->data.fd.fd > nfds) {
|
|
/* Remember this file descriptor: */
|
|
nfds = pthread->data.fd.fd;
|
|
}
|
|
/* Increment the file descriptor count: */
|
|
count++;
|
|
|
|
/* This state can time out: */
|
|
settimeout = 1;
|
|
break;
|
|
|
|
/* States that time out: */
|
|
case PS_SLEEP_WAIT:
|
|
case PS_COND_WAIT:
|
|
/* Flag a timeout as required: */
|
|
settimeout = 1;
|
|
break;
|
|
|
|
/* Select wait: */
|
|
case PS_SELECT_WAIT:
|
|
/*
|
|
* Enter a loop to process each file descriptor in
|
|
* the thread-specific file descriptor sets:
|
|
*/
|
|
for (i = 0; i < pthread->data.select_data->nfds; i++) {
|
|
/*
|
|
* Check if this file descriptor is set for
|
|
* exceptions:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->exceptfds)) {
|
|
/*
|
|
* Add the file descriptor to the
|
|
* exception set:
|
|
*/
|
|
FD_SET(i, &fd_set_except);
|
|
|
|
/*
|
|
* Increment the file descriptor
|
|
* count:
|
|
*/
|
|
count++;
|
|
|
|
/*
|
|
* Check if this file descriptor is
|
|
* greater than any of those seen so
|
|
* far:
|
|
*/
|
|
if (i > nfds) {
|
|
/*
|
|
* Remember this file
|
|
* descriptor:
|
|
*/
|
|
nfds = i;
|
|
}
|
|
}
|
|
/*
|
|
* Check if this file descriptor is set for
|
|
* write:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->writefds)) {
|
|
/*
|
|
* Add the file descriptor to the
|
|
* write set:
|
|
*/
|
|
FD_SET(i, &fd_set_write);
|
|
|
|
/*
|
|
* Increment the file descriptor
|
|
* count:
|
|
*/
|
|
count++;
|
|
|
|
/*
|
|
* Check if this file descriptor is
|
|
* greater than any of those seen so
|
|
* far:
|
|
*/
|
|
if (i > nfds) {
|
|
/*
|
|
* Remember this file
|
|
* descriptor:
|
|
*/
|
|
nfds = i;
|
|
}
|
|
}
|
|
/*
|
|
* Check if this file descriptor is set for
|
|
* read:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->readfds)) {
|
|
/*
|
|
* Add the file descriptor to the
|
|
* read set:
|
|
*/
|
|
FD_SET(i, &fd_set_read);
|
|
|
|
/*
|
|
* Increment the file descriptor
|
|
* count:
|
|
*/
|
|
count++;
|
|
|
|
/*
|
|
* Check if this file descriptor is
|
|
* greater than any of those seen so
|
|
* far:
|
|
*/
|
|
if (i > nfds) {
|
|
/*
|
|
* Remember this file
|
|
* descriptor:
|
|
*/
|
|
nfds = i;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* This state can time out: */
|
|
settimeout = 1;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* Check if the caller wants to wait and if the thread state
|
|
* is one that times out:
|
|
*/
|
|
if (wait_reqd && settimeout) {
|
|
/* Check if this thread wants to wait forever: */
|
|
if (pthread->wakeup_time.tv_sec == -1) {
|
|
}
|
|
/* Check if this thread doesn't want to wait at all: */
|
|
else if (pthread->wakeup_time.tv_sec == 0 &&
|
|
pthread->wakeup_time.tv_nsec == 0) {
|
|
/* Override the caller's request to wait: */
|
|
wait_reqd = 0;
|
|
} else {
|
|
/*
|
|
* Calculate the time until this thread is
|
|
* ready, allowing for the clock resolution:
|
|
*/
|
|
ts1.tv_sec = pthread->wakeup_time.tv_sec - ts.tv_sec;
|
|
ts1.tv_nsec = pthread->wakeup_time.tv_nsec - ts.tv_nsec +
|
|
CLOCK_RES_NSEC;
|
|
|
|
/*
|
|
* Check for underflow of the nanosecond
|
|
* field:
|
|
*/
|
|
if (ts1.tv_nsec < 0) {
|
|
/*
|
|
* Allow for the underflow of the
|
|
* nanosecond field:
|
|
*/
|
|
ts1.tv_sec--;
|
|
ts1.tv_nsec += 1000000000;
|
|
}
|
|
/*
|
|
* Check for overflow of the nanosecond
|
|
* field:
|
|
*/
|
|
if (ts1.tv_nsec >= 1000000000) {
|
|
/*
|
|
* Allow for the overflow of the
|
|
* nanosecond field:
|
|
*/
|
|
ts1.tv_sec++;
|
|
ts1.tv_nsec -= 1000000000;
|
|
}
|
|
/*
|
|
* Convert the timespec structure to a
|
|
* timeval structure:
|
|
*/
|
|
TIMESPEC_TO_TIMEVAL(&tv1, &ts1);
|
|
|
|
/*
|
|
* Check if no time value has been found yet,
|
|
* or if the thread will be ready sooner that
|
|
* the earliest one found so far:
|
|
*/
|
|
if ((tv.tv_sec == 0 && tv.tv_usec == 0) || timercmp(&tv1, &tv, <)) {
|
|
/* Update the time value: */
|
|
tv.tv_sec = tv1.tv_sec;
|
|
tv.tv_usec = tv1.tv_usec;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Check if the caller wants to wait: */
|
|
if (wait_reqd) {
|
|
/* Check if no threads were found with timeouts: */
|
|
if (tv.tv_sec == 0 && tv.tv_usec == 0) {
|
|
/* Wait forever: */
|
|
p_tv = NULL;
|
|
} else {
|
|
/*
|
|
* Point to the time value structure which contains
|
|
* the earliest time that a thread will be ready:
|
|
*/
|
|
p_tv = &tv;
|
|
}
|
|
|
|
/*
|
|
* Flag the pthread kernel as in a select. This is to avoid
|
|
* the window between the next statement that unblocks
|
|
* signals and the select statement which follows.
|
|
*/
|
|
_thread_kern_in_select = 1;
|
|
|
|
/*
|
|
* Wait for a file descriptor to be ready for read, write, or
|
|
* an exception, or a timeout to occur:
|
|
*/
|
|
count = _thread_sys_select(nfds + 1, &fd_set_read, &fd_set_write, &fd_set_except, p_tv);
|
|
|
|
/* Reset the kernel in select flag: */
|
|
_thread_kern_in_select = 0;
|
|
|
|
/*
|
|
* Check if it is possible that there are bytes in the kernel
|
|
* read pipe waiting to be read:
|
|
*/
|
|
if (count < 0 || FD_ISSET(_thread_kern_pipe[0], &fd_set_read)) {
|
|
/*
|
|
* Check if the kernel read pipe was included in the
|
|
* count:
|
|
*/
|
|
if (count > 0) {
|
|
/*
|
|
* Remove the kernel read pipe from the
|
|
* count:
|
|
*/
|
|
FD_CLR(_thread_kern_pipe[0], &fd_set_read);
|
|
|
|
/* Decrement the count of file descriptors: */
|
|
count--;
|
|
}
|
|
/*
|
|
* Enter a loop to read (and trash) bytes from the
|
|
* pthread kernel pipe:
|
|
*/
|
|
while ((num = _thread_sys_read(_thread_kern_pipe[0], bufr, sizeof(bufr))) > 0) {
|
|
/*
|
|
* The buffer read contains one byte per
|
|
* signal and each byte is the signal number.
|
|
* This data is not used, but the fact that
|
|
* the signal handler wrote to the pipe *is*
|
|
* used to cause the _select call
|
|
* to complete if the signal occurred between
|
|
* the time when signals were unblocked and
|
|
* the _select select call being
|
|
* made.
|
|
*/
|
|
}
|
|
}
|
|
}
|
|
/* Check if there are file descriptors to poll: */
|
|
else if (count > 0) {
|
|
/*
|
|
* Point to the time value structure which has been zeroed so
|
|
* that the call to _select will not wait:
|
|
*/
|
|
p_tv = &tv;
|
|
|
|
/* Poll file descrptors without wait: */
|
|
count = _thread_sys_select(nfds + 1, &fd_set_read, &fd_set_write, &fd_set_except, p_tv);
|
|
}
|
|
|
|
/*
|
|
* Check if any file descriptors are ready:
|
|
*/
|
|
if (count > 0) {
|
|
/*
|
|
* Enter a loop to look for threads waiting on file
|
|
* descriptors that are flagged as available by the
|
|
* _select syscall:
|
|
*/
|
|
for (pthread = _thread_link_list; pthread != NULL; pthread = pthread->nxt) {
|
|
/* Process according to thread state: */
|
|
switch (pthread->state) {
|
|
/*
|
|
* States which do not depend on file
|
|
* descriptor I/O operations:
|
|
*/
|
|
case PS_RUNNING:
|
|
case PS_COND_WAIT:
|
|
case PS_DEAD:
|
|
case PS_FDLR_WAIT:
|
|
case PS_FDLW_WAIT:
|
|
case PS_FILE_WAIT:
|
|
case PS_JOIN:
|
|
case PS_MUTEX_WAIT:
|
|
case PS_SIGWAIT:
|
|
case PS_SLEEP_WAIT:
|
|
case PS_WAIT_WAIT:
|
|
case PS_SIGTHREAD:
|
|
case PS_STATE_MAX:
|
|
case PS_SUSPENDED:
|
|
/* Nothing to do here. */
|
|
break;
|
|
|
|
/* File descriptor read wait: */
|
|
case PS_FDR_WAIT:
|
|
/*
|
|
* Check if the file descriptor is available
|
|
* for read:
|
|
*/
|
|
if (FD_ISSET(pthread->data.fd.fd, &fd_set_read)) {
|
|
/*
|
|
* Change the thread state to allow
|
|
* it to read from the file when it
|
|
* is scheduled next:
|
|
*/
|
|
pthread->state = PS_RUNNING;
|
|
}
|
|
break;
|
|
|
|
/* File descriptor write wait: */
|
|
case PS_FDW_WAIT:
|
|
/*
|
|
* Check if the file descriptor is available
|
|
* for write:
|
|
*/
|
|
if (FD_ISSET(pthread->data.fd.fd, &fd_set_write)) {
|
|
/*
|
|
* Change the thread state to allow
|
|
* it to write to the file when it is
|
|
* scheduled next:
|
|
*/
|
|
pthread->state = PS_RUNNING;
|
|
}
|
|
break;
|
|
|
|
/* Select wait: */
|
|
case PS_SELECT_WAIT:
|
|
/*
|
|
* Reset the flag that indicates if a file
|
|
* descriptor is ready for some type of
|
|
* operation:
|
|
*/
|
|
count_dec = 0;
|
|
|
|
/*
|
|
* Enter a loop to search though the
|
|
* thread-specific select file descriptors
|
|
* for the first descriptor that is ready:
|
|
*/
|
|
for (i = 0; i < pthread->data.select_data->nfds && count_dec == 0; i++) {
|
|
/*
|
|
* Check if this file descriptor does
|
|
* not have an exception:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->exceptfds) && FD_ISSET(i, &fd_set_except)) {
|
|
/*
|
|
* Flag this file descriptor
|
|
* as ready:
|
|
*/
|
|
count_dec = 1;
|
|
}
|
|
/*
|
|
* Check if this file descriptor is
|
|
* not ready for write:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->writefds) && FD_ISSET(i, &fd_set_write)) {
|
|
/*
|
|
* Flag this file descriptor
|
|
* as ready:
|
|
*/
|
|
count_dec = 1;
|
|
}
|
|
/*
|
|
* Check if this file descriptor is
|
|
* not ready for read:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->readfds) && FD_ISSET(i, &fd_set_read)) {
|
|
/*
|
|
* Flag this file descriptor
|
|
* as ready:
|
|
*/
|
|
count_dec = 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Check if any file descriptors are ready
|
|
* for the current thread:
|
|
*/
|
|
if (count_dec) {
|
|
/*
|
|
* Reset the count of file
|
|
* descriptors that are ready for
|
|
* this thread:
|
|
*/
|
|
found_one = 0;
|
|
|
|
/*
|
|
* Enter a loop to search though the
|
|
* thread-specific select file
|
|
* descriptors:
|
|
*/
|
|
for (i = 0; i < pthread->data.select_data->nfds; i++) {
|
|
/*
|
|
* Reset the count of
|
|
* operations for which the
|
|
* current file descriptor is
|
|
* ready:
|
|
*/
|
|
count_dec = 0;
|
|
|
|
/*
|
|
* Check if this file
|
|
* descriptor is selected for
|
|
* exceptions:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->exceptfds)) {
|
|
/*
|
|
* Check if this file
|
|
* descriptor has an
|
|
* exception:
|
|
*/
|
|
if (FD_ISSET(i, &fd_set_except)) {
|
|
/*
|
|
* Increment
|
|
* the count
|
|
* for this
|
|
* file:
|
|
*/
|
|
count_dec++;
|
|
} else {
|
|
/*
|
|
* Clear the
|
|
* file
|
|
* descriptor
|
|
* in the
|
|
* thread-spec
|
|
* ific file
|
|
* descriptor
|
|
* set:
|
|
*/
|
|
FD_CLR(i, &pthread->data.select_data->exceptfds);
|
|
}
|
|
}
|
|
/*
|
|
* Check if this file
|
|
* descriptor is selected for
|
|
* write:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->writefds)) {
|
|
/*
|
|
* Check if this file
|
|
* descriptor is
|
|
* ready for write:
|
|
*/
|
|
if (FD_ISSET(i, &fd_set_write)) {
|
|
/*
|
|
* Increment
|
|
* the count
|
|
* for this
|
|
* file:
|
|
*/
|
|
count_dec++;
|
|
} else {
|
|
/*
|
|
* Clear the
|
|
* file
|
|
* descriptor
|
|
* in the
|
|
* thread-spec
|
|
* ific file
|
|
* descriptor
|
|
* set:
|
|
*/
|
|
FD_CLR(i, &pthread->data.select_data->writefds);
|
|
}
|
|
}
|
|
/*
|
|
* Check if this file
|
|
* descriptor is selected for
|
|
* read:
|
|
*/
|
|
if (FD_ISSET(i, &pthread->data.select_data->readfds)) {
|
|
/*
|
|
* Check if this file
|
|
* descriptor is
|
|
* ready for read:
|
|
*/
|
|
if (FD_ISSET(i, &fd_set_read)) {
|
|
/*
|
|
* Increment
|
|
* the count
|
|
* for this
|
|
* file:
|
|
*/
|
|
count_dec++;
|
|
} else {
|
|
/*
|
|
* Clear the
|
|
* file
|
|
* descriptor
|
|
* in the
|
|
* thread-spec
|
|
* ific file
|
|
* descriptor
|
|
* set:
|
|
*/
|
|
FD_CLR(i, &pthread->data.select_data->readfds);
|
|
}
|
|
}
|
|
/*
|
|
* Check if the current file
|
|
* descriptor is ready for
|
|
* any one of the operations:
|
|
*/
|
|
if (count_dec > 0) {
|
|
/*
|
|
* Increment the
|
|
* count of file
|
|
* descriptors that
|
|
* are ready for the
|
|
* current thread:
|
|
*/
|
|
found_one++;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Return the number of file
|
|
* descriptors that are ready:
|
|
*/
|
|
pthread->data.select_data->nfds = found_one;
|
|
|
|
/*
|
|
* Change the state of the current
|
|
* thread to run:
|
|
*/
|
|
pthread->state = PS_RUNNING;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Nothing to return. */
|
|
return;
|
|
}
|
|
|
|
void
|
|
_thread_kern_set_timeout(struct timespec * timeout)
|
|
{
|
|
struct timespec current_time;
|
|
struct timeval tv;
|
|
|
|
/* Reset the timeout flag for the running thread: */
|
|
_thread_run->timeout = 0;
|
|
|
|
/* Check if the thread is to wait forever: */
|
|
if (timeout == NULL) {
|
|
/*
|
|
* Set the wakeup time to something that can be recognised as
|
|
* different to an actual time of day:
|
|
*/
|
|
_thread_run->wakeup_time.tv_sec = -1;
|
|
_thread_run->wakeup_time.tv_nsec = -1;
|
|
}
|
|
/* Check if no waiting is required: */
|
|
else if (timeout->tv_sec == 0 && timeout->tv_nsec == 0) {
|
|
/* Set the wake up time to 'immediately': */
|
|
_thread_run->wakeup_time.tv_sec = 0;
|
|
_thread_run->wakeup_time.tv_nsec = 0;
|
|
} else {
|
|
/* Get the current time: */
|
|
gettimeofday(&tv, NULL);
|
|
TIMEVAL_TO_TIMESPEC(&tv, ¤t_time);
|
|
|
|
/* Calculate the time for the current thread to wake up: */
|
|
_thread_run->wakeup_time.tv_sec = current_time.tv_sec + timeout->tv_sec;
|
|
_thread_run->wakeup_time.tv_nsec = current_time.tv_nsec + timeout->tv_nsec;
|
|
|
|
/* Check if the nanosecond field needs to wrap: */
|
|
if (_thread_run->wakeup_time.tv_nsec >= 1000000000) {
|
|
/* Wrap the nanosecond field: */
|
|
_thread_run->wakeup_time.tv_sec += 1;
|
|
_thread_run->wakeup_time.tv_nsec -= 1000000000;
|
|
}
|
|
}
|
|
return;
|
|
}
|
|
#endif
|