Commit c93bbbef authored by Alex Bennée's avatar Alex Bennée Committed by Paolo Bonzini
Browse files

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: default avatarAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: default avatarSergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: default avatarRichard Henderson <rth@twiddle.net>

Message-Id: <20161027151030.20863-13-alex.bennee@linaro.org>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 1be7fcb8

cpus.c

+43 −44
Original line number Diff line number Diff line
@@ -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;



    /* 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);

    CPUState *cpu;



        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;