On 5/22/20 6:07 PM, Robert Foley wrote:
> From: "Emilio G. Cota" <c...@braap.org>
>
> Instead of open-coding it.
Please use a full sentence (repeating the patch subject):
"Convert queued work to a QSIMPLEQ instead of open-coding it."
(Not all email clients display the subject preceding the content).
Otherwise:
Reviewed-by: Philippe Mathieu-Daudé <phi...@redhat.com>
>
> While at it, make sure that all accesses to the list are
> performed while holding the list's lock.
>
> Reviewed-by: Richard Henderson <richard.hender...@linaro.org>
> Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
> Signed-off-by: Emilio G. Cota <c...@braap.org>
> Signed-off-by: Robert Foley <robert.fo...@linaro.org>
> ---
> cpus-common.c | 25 ++++++++-----------------
> cpus.c | 14 ++++++++++++--
> hw/core/cpu.c | 1 +
> include/hw/core/cpu.h | 6 +++---
> 4 files changed, 24 insertions(+), 22 deletions(-)
>
> diff --git a/cpus-common.c b/cpus-common.c
> index 55d5df8923..210fc7fc39 100644
> --- a/cpus-common.c
> +++ b/cpus-common.c
> @@ -97,7 +97,7 @@ void cpu_list_remove(CPUState *cpu)
> }
>
> struct qemu_work_item {
> - struct qemu_work_item *next;
> + QSIMPLEQ_ENTRY(qemu_work_item) node;
> run_on_cpu_func func;
> run_on_cpu_data data;
> bool free, exclusive, done;
> @@ -106,13 +106,7 @@ struct qemu_work_item {
> static void queue_work_on_cpu(CPUState *cpu, struct qemu_work_item *wi)
> {
> qemu_mutex_lock(&cpu->work_mutex);
> - if (cpu->queued_work_first == NULL) {
> - cpu->queued_work_first = wi;
> - } else {
> - cpu->queued_work_last->next = wi;
> - }
> - cpu->queued_work_last = wi;
> - wi->next = NULL;
> + QSIMPLEQ_INSERT_TAIL(&cpu->work_list, wi, node);
> wi->done = false;
> qemu_mutex_unlock(&cpu->work_mutex);
>
> @@ -306,17 +300,14 @@ void process_queued_cpu_work(CPUState *cpu)
> {
> struct qemu_work_item *wi;
>
> - if (cpu->queued_work_first == NULL) {
> + qemu_mutex_lock(&cpu->work_mutex);
> + if (QSIMPLEQ_EMPTY(&cpu->work_list)) {
> + qemu_mutex_unlock(&cpu->work_mutex);
> return;
> }
> -
> - qemu_mutex_lock(&cpu->work_mutex);
> - while (cpu->queued_work_first != NULL) {
> - wi = cpu->queued_work_first;
> - cpu->queued_work_first = wi->next;
> - if (!cpu->queued_work_first) {
> - cpu->queued_work_last = NULL;
> - }
> + while (!QSIMPLEQ_EMPTY(&cpu->work_list)) {
> + wi = QSIMPLEQ_FIRST(&cpu->work_list);
> + QSIMPLEQ_REMOVE_HEAD(&cpu->work_list, node);
> qemu_mutex_unlock(&cpu->work_mutex);
> if (wi->exclusive) {
> /* Running work items outside the BQL avoids the following
> deadlock:
> diff --git a/cpus.c b/cpus.c
> index 5670c96bcf..af44027549 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -97,9 +97,19 @@ bool cpu_is_stopped(CPUState *cpu)
> return cpu->stopped || !runstate_is_running();
> }
>
> +static inline bool cpu_work_list_empty(CPUState *cpu)
> +{
> + bool ret;
> +
> + qemu_mutex_lock(&cpu->work_mutex);
> + ret = QSIMPLEQ_EMPTY(&cpu->work_list);
> + qemu_mutex_unlock(&cpu->work_mutex);
> + return ret;
> +}
> +
> static bool cpu_thread_is_idle(CPUState *cpu)
> {
> - if (cpu->stop || cpu->queued_work_first) {
> + if (cpu->stop || !cpu_work_list_empty(cpu)) {
> return false;
> }
> if (cpu_is_stopped(cpu)) {
> @@ -1498,7 +1508,7 @@ static void *qemu_tcg_rr_cpu_thread_fn(void *arg)
> cpu = first_cpu;
> }
>
> - while (cpu && !cpu->queued_work_first && !cpu->exit_request) {
> + while (cpu && cpu_work_list_empty(cpu) && !cpu->exit_request) {
>
> atomic_mb_set(&tcg_current_rr_cpu, cpu);
> current_cpu = cpu;
> diff --git a/hw/core/cpu.c b/hw/core/cpu.c
> index 5284d384fb..77703d62b7 100644
> --- a/hw/core/cpu.c
> +++ b/hw/core/cpu.c
> @@ -368,6 +368,7 @@ static void cpu_common_initfn(Object *obj)
> cpu->nr_threads = 1;
>
> qemu_mutex_init(&cpu->work_mutex);
> + QSIMPLEQ_INIT(&cpu->work_list);
> QTAILQ_INIT(&cpu->breakpoints);
> QTAILQ_INIT(&cpu->watchpoints);
>
> diff --git a/include/hw/core/cpu.h b/include/hw/core/cpu.h
> index 07f7698155..d78ff1d165 100644
> --- a/include/hw/core/cpu.h
> +++ b/include/hw/core/cpu.h
> @@ -331,8 +331,8 @@ struct qemu_work_item;
> * @opaque: User data.
> * @mem_io_pc: Host Program Counter at which the memory was accessed.
> * @kvm_fd: vCPU file descriptor for KVM.
> - * @work_mutex: Lock to prevent multiple access to queued_work_*.
> - * @queued_work_first: First asynchronous work pending.
> + * @work_mutex: Lock to prevent multiple access to @work_list.
> + * @work_list: List of pending asynchronous work.
> * @trace_dstate_delayed: Delayed changes to trace_dstate (includes all
> changes
> * to @trace_dstate).
> * @trace_dstate: Dynamic tracing state of events for this vCPU (bitmask).
> @@ -376,7 +376,7 @@ struct CPUState {
> sigjmp_buf jmp_env;
>
> QemuMutex work_mutex;
> - struct qemu_work_item *queued_work_first, *queued_work_last;
> + QSIMPLEQ_HEAD(, qemu_work_item) work_list;
>
> CPUAddressSpace *cpu_ases;
> int num_ases;
>
