| Message ID | 20181025144644.15464-1-cota@braap.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [RFC,v4,01/71] cpu: convert queued work to a QSIMPLEQ | expand |
Emilio G. Cota <cota@braap.org> writes: > Instead of open-coding it. > > While at it, make sure that all accesses to the list are > performed while holding the list's lock. > > Reviewed-by: Richard Henderson <richard.henderson@linaro.org> > Signed-off-by: Emilio G. Cota <cota@braap.org> > --- > include/qom/cpu.h | 6 +++--- > cpus-common.c | 25 ++++++++----------------- > cpus.c | 14 ++++++++++++-- > qom/cpu.c | 1 + > 4 files changed, 24 insertions(+), 22 deletions(-) > > diff --git a/include/qom/cpu.h b/include/qom/cpu.h > index dc130cd307..53488b202f 100644 > --- a/include/qom/cpu.h > +++ b/include/qom/cpu.h > @@ -315,8 +315,8 @@ struct qemu_work_item; > * @mem_io_pc: Host Program Counter at which the memory was accessed. > * @mem_io_vaddr: Target virtual address 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). > @@ -357,7 +357,7 @@ 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; Would: QSIMPLEQ_HEAD(work_list, qemu_work_item); be neater? > > CPUAddressSpace *cpu_ases; > int num_ases; > diff --git a/cpus-common.c b/cpus-common.c > index 98dd8c6ff1..a2a6cd93a1 100644 > --- a/cpus-common.c > +++ b/cpus-common.c > @@ -107,7 +107,7 @@ 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; > @@ -116,13 +116,7 @@ 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); > > @@ -314,17 +308,14 @@ 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 cce64874e6..6d86522031 100644 > --- a/cpus.c > +++ b/cpus.c > @@ -88,9 +88,19 @@ 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; This could just be: return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list) > +} > + > 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)) { > @@ -1509,7 +1519,7 @@ 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/qom/cpu.c b/qom/cpu.c > index 20ad54d43f..c47169896e 100644 > --- a/qom/cpu.c > +++ b/qom/cpu.c > @@ -373,6 +373,7 @@ 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); Otherwise: Reviewed-by: Alex Bennée <alex.bennee@linaro.org> -- Alex Bennée
On Mon, Oct 29, 2018 at 15:39:29 +0000, Alex Bennée wrote: > > Emilio G. Cota <cota@braap.org> writes: (snip) > > @@ -357,7 +357,7 @@ 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; > > Would: > > QSIMPLEQ_HEAD(work_list, qemu_work_item); > > be neater? That would expand to struct CPUState { ... struct work_list { struct qemu_work_item *sqh_first; struct qemu_work_item **sqh_last; }; // <-- missing field name ... }; , which doesn't declare an actual field in the struct. > > +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; > > This could just be: > > return QSIMPLEQ_EMPTY_ATOMIC(&cpu->work_list) Not quite; (1) the non-RCU version of the list does not set pointers with atomic_set, so an atomic_read here would not be enough, and (2) using the lock ensures that the read is up-to-date. These two points are not a big deal though, since later in the series ("cpu: protect most CPU state with cpu->lock") we hold the CPU lock when calling this. > Otherwise: > > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Thanks! Emilio
diff --git a/include/qom/cpu.h b/include/qom/cpu.h index dc130cd307..53488b202f 100644 --- a/include/qom/cpu.h +++ b/include/qom/cpu.h @@ -315,8 +315,8 @@ struct qemu_work_item; * @mem_io_pc: Host Program Counter at which the memory was accessed. * @mem_io_vaddr: Target virtual address 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). @@ -357,7 +357,7 @@ 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; diff --git a/cpus-common.c b/cpus-common.c index 98dd8c6ff1..a2a6cd93a1 100644 --- a/cpus-common.c +++ b/cpus-common.c @@ -107,7 +107,7 @@ 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; @@ -116,13 +116,7 @@ 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); @@ -314,17 +308,14 @@ 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 cce64874e6..6d86522031 100644 --- a/cpus.c +++ b/cpus.c @@ -88,9 +88,19 @@ 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)) { @@ -1509,7 +1519,7 @@ 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/qom/cpu.c b/qom/cpu.c index 20ad54d43f..c47169896e 100644 --- a/qom/cpu.c +++ b/qom/cpu.c @@ -373,6 +373,7 @@ 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);