tcg: cpus rm tcg_exec_all()

In preparation for multi-threaded TCG we remove tcg_exec_all and move
all the CPU cycling into the main thread function. When MTTCG is enabled
we shall use a separate thread function which only handles one vCPU.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>

Message-Id: <20161027151030.20863-13-alex.bennee@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alex Bennée 2016-10-27 16:10:09 +01:00 committed by Paolo Bonzini
parent 1be7fcb8aa
commit c93bbbefca

87
cpus.c
View file

@ -69,7 +69,6 @@
#endif /* CONFIG_LINUX */
static CPUState *next_cpu;
int64_t max_delay;
int64_t max_advance;
@ -1119,46 +1118,26 @@ static int tcg_cpu_exec(CPUState *cpu)
return ret;
}
static void tcg_exec_all(void)
/* Destroy any remaining vCPUs which have been unplugged and have
* finished running
*/
static void deal_with_unplugged_cpus(void)
{
int r;
CPUState *cpu;
/* Account partial waits to QEMU_CLOCK_VIRTUAL. */
qemu_account_warp_timer();
if (next_cpu == NULL) {
next_cpu = first_cpu;
}
for (; next_cpu != NULL && !exit_request; next_cpu = CPU_NEXT(next_cpu)) {
CPUState *cpu = next_cpu;
qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
(cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);
if (cpu_can_run(cpu)) {
r = tcg_cpu_exec(cpu);
if (r == EXCP_DEBUG) {
cpu_handle_guest_debug(cpu);
break;
} else if (r == EXCP_ATOMIC) {
cpu_exec_step_atomic(cpu);
}
} else if (cpu->stop || cpu->stopped) {
if (cpu->unplug) {
next_cpu = CPU_NEXT(cpu);
}
CPU_FOREACH(cpu) {
if (cpu->unplug && !cpu_can_run(cpu)) {
qemu_tcg_destroy_vcpu(cpu);
cpu->created = false;
qemu_cond_signal(&qemu_cpu_cond);
break;
}
}
/* Pairs with smp_wmb in qemu_cpu_kick. */
atomic_mb_set(&exit_request, 0);
}
static void *qemu_tcg_cpu_thread_fn(void *arg)
{
CPUState *cpu = arg;
CPUState *remove_cpu = NULL;
rcu_register_thread();
@ -1185,8 +1164,39 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
/* process any pending work */
atomic_mb_set(&exit_request, 1);
cpu = first_cpu;
while (1) {
tcg_exec_all();
/* Account partial waits to QEMU_CLOCK_VIRTUAL. */
qemu_account_warp_timer();
if (!cpu) {
cpu = first_cpu;
}
for (; cpu != NULL && !exit_request; cpu = CPU_NEXT(cpu)) {
qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
(cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);
if (cpu_can_run(cpu)) {
int r;
r = tcg_cpu_exec(cpu);
if (r == EXCP_DEBUG) {
cpu_handle_guest_debug(cpu);
break;
}
} else if (cpu->stop || cpu->stopped) {
if (cpu->unplug) {
cpu = CPU_NEXT(cpu);
}
break;
}
} /* for cpu.. */
/* Pairs with smp_wmb in qemu_cpu_kick. */
atomic_mb_set(&exit_request, 0);
if (use_icount) {
int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
@ -1196,18 +1206,7 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
}
}
qemu_tcg_wait_io_event(QTAILQ_FIRST(&cpus));
CPU_FOREACH(cpu) {
if (cpu->unplug && !cpu_can_run(cpu)) {
remove_cpu = cpu;
break;
}
}
if (remove_cpu) {
qemu_tcg_destroy_vcpu(remove_cpu);
cpu->created = false;
qemu_cond_signal(&qemu_cpu_cond);
remove_cpu = NULL;
}
deal_with_unplugged_cpus();
}
return NULL;