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* Recycle upcall stacks as soon as possible rather than waiting to 

accumulate half of the total number. There are too many ways for
  the SA subsystem to deadlock waiting for stacks that userland has no
  reason to recycle.

* Consolidate switchto handling in pthread_resolve_locks().

* Add code to re-chain the preempting parents of switchtos.

* Tweak debuglog output in a couple of cases.
This commit is contained in:
nathanw 2003-05-26 19:41:03 +00:00
parent c7bcda3906
commit 5faa7f5bef
1 changed files with 51 additions and 82 deletions
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117
lib/libpthread/pthread_sa.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: pthread_sa.c,v 1.7 2003/03/08 08:03:35 lukem Exp $ */
/* $NetBSD: pthread_sa.c,v 1.8 2003/05/26 19:41:03 nathanw Exp $ */
/*-
* Copyright (c) 2001 The NetBSD Foundation, Inc.
@ -37,7 +37,7 @@
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: pthread_sa.c,v 1.7 2003/03/08 08:03:35 lukem Exp $");
__RCSID("$NetBSD: pthread_sa.c,v 1.8 2003/05/26 19:41:03 nathanw Exp $");
#include <err.h>
#include <errno.h>
@ -62,12 +62,6 @@ __RCSID("$NetBSD: pthread_sa.c,v 1.7 2003/03/08 08:03:35 lukem Exp $");
extern struct pthread_queue_t pthread__allqueue;
static stack_t recyclable[2][(PT_UPCALLSTACKS/2)+1];
static int recycle_count;
static int recycle_threshold;
static int recycle_side;
static pthread_spin_t recycle_lock;
#define PTHREAD_RRTIMER_INTERVAL_DEFAULT 100
static pthread_mutex_t rrtimer_mutex = PTHREAD_MUTEX_INITIALIZER;
static timer_t pthread_rrtimer;
@ -138,6 +132,9 @@ pthread__upcall(int type, struct sa_t *sas[], int ev, int intr, void *arg)
t->blocks++;
#endif
t->pt_uc = sas[1]->sa_context;
SDPRINTF(("(up %p) blocker %d %p(%d)\n", self, 1, t,
t->pt_type));
PTHREADD_ADD(PTHREADD_UP_BLOCK);
break;
case SA_UPCALL_NEWPROC:
@ -325,6 +322,7 @@ void
pthread__resolve_locks(pthread_t self, pthread_t *intqueuep)
{
pthread_t victim, prev, next, switchto, runq, recycleq, intqueue;
pthread_t tmp;
pthread_spin_t *lock;
PTHREADD_ADD(PTHREADD_RESOLVELOCKS);
@ -349,14 +347,6 @@ pthread__resolve_locks(pthread_t self, pthread_t *intqueuep)
next = victim->pt_next;
SDPRINTF(("(rl %p) victim %p (uc %p)", self,
victim, victim->pt_uc));
if (victim->pt_switchto) {
PTHREADD_ADD(PTHREADD_SWITCHTO);
switchto = victim->pt_switchto;
switchto->pt_uc = victim->pt_switchtouc;
victim->pt_switchto = NULL;
victim->pt_switchtouc = NULL;
SDPRINTF((" switchto: %p", switchto));
}
if (victim->pt_type == PT_THREAD_NORMAL) {
SDPRINTF((" normal"));
@ -458,7 +448,15 @@ pthread__resolve_locks(pthread_t self, pthread_t *intqueuep)
}
}
if (switchto) {
if (victim->pt_switchto) {
PTHREADD_ADD(PTHREADD_SWITCHTO);
switchto = victim->pt_switchto;
switchto->pt_uc = victim->pt_switchtouc;
victim->pt_switchto = NULL;
victim->pt_switchtouc = NULL;
SDPRINTF((" switchto: %p (uc %p)", switchto,
switchto->pt_uc));
pthread__assert(switchto->pt_spinlocks == 0);
/*
* Threads can have switchto set to themselves
@ -466,9 +464,27 @@ pthread__resolve_locks(pthread_t self, pthread_t *intqueuep)
* on the run queue twice.
*/
if (switchto != victim) {
if (switchto->pt_next) {
/*
* The thread being switched
* to was preempted and
* continued. Find the
* preempter and put it on
* our continuation chain.
*/
SDPRINTF((" switchto chained"));
for ( tmp = switchto;
tmp->pt_parent != NULL;
tmp = tmp->pt_parent)
SDPRINTF((" parent: %p", tmp));
tmp->pt_parent = self;
tmp->pt_next = intqueue;
intqueue = tmp;
} else {
switchto->pt_next = runq;
runq = switchto;
}
}
switchto = NULL;
}
SDPRINTF(("\n"));
@ -515,45 +531,24 @@ pthread__resolve_locks(pthread_t self, pthread_t *intqueuep)
void
pthread__recycle_bulk(pthread_t self, pthread_t qhead)
{
int do_recycle, my_side, ret;
int count, ret;
pthread_t upcall;
stack_t recyclable[PT_UPCALLSTACKS];
count = 0;
while(qhead != NULL) {
pthread_spinlock(self, &recycle_lock);
my_side = recycle_side;
do_recycle = 0;
while ((qhead != NULL) &&
(recycle_count < recycle_threshold)) {
upcall = qhead;
qhead = qhead->pt_next;
upcall->pt_state = PT_STATE_RUNNABLE;
upcall->pt_next = NULL;
upcall->pt_parent = NULL;
recyclable[my_side][recycle_count] = upcall->pt_stack;
recycle_count++;
}
SDPRINTF(("(recycle_bulk %p) count %d\n", self, recycle_count));
if (recycle_count == recycle_threshold) {
recycle_side = 1 - recycle_side;
recycle_count = 0;
do_recycle = 1;
}
pthread_spinunlock(self, &recycle_lock);
if (do_recycle) {
SDPRINTF(("(recycle_bulk %p) recycled %d stacks\n", self, recycle_threshold));
ret = sa_stacks(recycle_threshold,
recyclable[my_side]);
if (ret != recycle_threshold) {
printf("Error: recycle_threshold\n");
printf("ret: %d threshold: %d\n",
ret, recycle_threshold);
/*CONSTCOND*/
pthread__assert(0);
}
}
recyclable[count] = upcall->pt_stack;
count++;
}
ret = sa_stacks(count, recyclable);
pthread__assert(ret == count);
SDPRINTF(("(recycle_bulk %p) recycled %d stacks\n", self, count));
}
/*
@ -563,37 +558,13 @@ pthread__recycle_bulk(pthread_t self, pthread_t qhead)
void
pthread__sa_recycle(pthread_t old, pthread_t new)
{
int do_recycle, my_side, ret;
do_recycle = 0;
old->pt_next = NULL;
old->pt_parent = NULL;
old->pt_state = PT_STATE_RUNNABLE;
pthread_spinlock(new, &recycle_lock);
my_side = recycle_side;
recyclable[my_side][recycle_count] = old->pt_stack;
recycle_count++;
SDPRINTF(("(recycle %p) count %d\n", new, recycle_count));
if (recycle_count == recycle_threshold) {
/* Switch */
recycle_side = 1 - recycle_side;
recycle_count = 0;
do_recycle = 1;
}
pthread_spinunlock(new, &recycle_lock);
if (do_recycle) {
ret = sa_stacks(recycle_threshold, recyclable[my_side]);
SDPRINTF(("(recycle %p) recycled %d stacks\n", new, recycle_threshold));
if (ret != recycle_threshold) {
/*CONSTCOND*/
pthread__assert(0);
}
}
sa_stacks(1, &old->pt_stack);
SDPRINTF(("(recycle %p) recycled %p\n", new, old));
}
/*
@ -678,8 +649,6 @@ pthread__sa_start(void)
PTQ_INSERT_HEAD(&pthread__allqueue, t, pt_allq);
}
recycle_threshold = PT_UPCALLSTACKS/2;
ret = sa_stacks(i, upcall_stacks);
if (ret == -1)
abort();