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Pull request 

- Add new thread-pool-min/thread-pool-max parameters to control the thread pool
   used for async I/O.
 
 - Fix virtio-scsi IOThread 100% CPU consumption QEMU 7.0 regression.
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Merge tag 'block-pull-request' of https://gitlab.com/stefanha/qemu into staging

Pull request

- Add new thread-pool-min/thread-pool-max parameters to control the thread pool
  used for async I/O.

- Fix virtio-scsi IOThread 100% CPU consumption QEMU 7.0 regression.

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# gpg: Signature made Mon 09 May 2022 05:52:56 AM PDT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [full]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [full]

* tag 'block-pull-request' of https://gitlab.com/stefanha/qemu:
  virtio-scsi: move request-related items from .h to .c
  virtio-scsi: clean up virtio_scsi_handle_cmd_vq()
  virtio-scsi: clean up virtio_scsi_handle_ctrl_vq()
  virtio-scsi: clean up virtio_scsi_handle_event_vq()
  virtio-scsi: don't waste CPU polling the event virtqueue
  virtio-scsi: fix ctrl and event handler functions in dataplane mode
  util/event-loop-base: Introduce options to set the thread pool size
  util/main-loop: Introduce the main loop into QOM
  Introduce event-loop-base abstract class

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-05-09 11:07:04 -07:00
parent b0c3c60366 3dc584abee
commit 178bacb66d
18 changed files with 505 additions and 143 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

140
event-loop-base.c Normal file
View File

@ -0,0 +1,140 @@
/*
* QEMU event-loop base
*
* Copyright (C) 2022 Red Hat Inc
*
* Authors:
* Stefan Hajnoczi <stefanha@redhat.com>
* Nicolas Saenz Julienne <nsaenzju@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qom/object_interfaces.h"
#include "qapi/error.h"
#include "block/thread-pool.h"
#include "sysemu/event-loop-base.h"
typedef struct {
const char *name;
ptrdiff_t offset; /* field's byte offset in EventLoopBase struct */
} EventLoopBaseParamInfo;
static void event_loop_base_instance_init(Object *obj)
{
EventLoopBase *base = EVENT_LOOP_BASE(obj);
base->thread_pool_max = THREAD_POOL_MAX_THREADS_DEFAULT;
}
static EventLoopBaseParamInfo aio_max_batch_info = {
"aio-max-batch", offsetof(EventLoopBase, aio_max_batch),
};
static EventLoopBaseParamInfo thread_pool_min_info = {
"thread-pool-min", offsetof(EventLoopBase, thread_pool_min),
};
static EventLoopBaseParamInfo thread_pool_max_info = {
"thread-pool-max", offsetof(EventLoopBase, thread_pool_max),
};
static void event_loop_base_get_param(Object *obj, Visitor *v,
const char *name, void *opaque, Error **errp)
{
EventLoopBase *event_loop_base = EVENT_LOOP_BASE(obj);
EventLoopBaseParamInfo *info = opaque;
int64_t *field = (void *)event_loop_base + info->offset;
visit_type_int64(v, name, field, errp);
}
static void event_loop_base_set_param(Object *obj, Visitor *v,
const char *name, void *opaque, Error **errp)
{
EventLoopBaseClass *bc = EVENT_LOOP_BASE_GET_CLASS(obj);
EventLoopBase *base = EVENT_LOOP_BASE(obj);
EventLoopBaseParamInfo *info = opaque;
int64_t *field = (void *)base + info->offset;
int64_t value;
if (!visit_type_int64(v, name, &value, errp)) {
return;
}
if (value < 0) {
error_setg(errp, "%s value must be in range [0, %" PRId64 "]",
info->name, INT64_MAX);
return;
}
*field = value;
if (bc->update_params) {
bc->update_params(base, errp);
}
return;
}
static void event_loop_base_complete(UserCreatable *uc, Error **errp)
{
EventLoopBaseClass *bc = EVENT_LOOP_BASE_GET_CLASS(uc);
EventLoopBase *base = EVENT_LOOP_BASE(uc);
if (bc->init) {
bc->init(base, errp);
}
}
static bool event_loop_base_can_be_deleted(UserCreatable *uc)
{
EventLoopBaseClass *bc = EVENT_LOOP_BASE_GET_CLASS(uc);
EventLoopBase *backend = EVENT_LOOP_BASE(uc);
if (bc->can_be_deleted) {
return bc->can_be_deleted(backend);
}
return true;
}
static void event_loop_base_class_init(ObjectClass *klass, void *class_data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
ucc->complete = event_loop_base_complete;
ucc->can_be_deleted = event_loop_base_can_be_deleted;
object_class_property_add(klass, "aio-max-batch", "int",
event_loop_base_get_param,
event_loop_base_set_param,
NULL, &aio_max_batch_info);
object_class_property_add(klass, "thread-pool-min", "int",
event_loop_base_get_param,
event_loop_base_set_param,
NULL, &thread_pool_min_info);
object_class_property_add(klass, "thread-pool-max", "int",
event_loop_base_get_param,
event_loop_base_set_param,
NULL, &thread_pool_max_info);
}
static const TypeInfo event_loop_base_info = {
.name = TYPE_EVENT_LOOP_BASE,
.parent = TYPE_OBJECT,
.instance_size = sizeof(EventLoopBase),
.instance_init = event_loop_base_instance_init,
.class_size = sizeof(EventLoopBaseClass),
.class_init = event_loop_base_class_init,
.abstract = true,
.interfaces = (InterfaceInfo[]) {
{ TYPE_USER_CREATABLE },
{ }
}
};
static void register_types(void)
{
type_register_static(&event_loop_base_info);
}
type_init(register_types);

2
hw/scsi/virtio-scsi-dataplane.c
View File

@ -138,7 +138,7 @@ int virtio_scsi_dataplane_start(VirtIODevice *vdev)
aio_context_acquire(s->ctx);
virtio_queue_aio_attach_host_notifier(vs->ctrl_vq, s->ctx);
virtio_queue_aio_attach_host_notifier(vs->event_vq, s->ctx);
virtio_queue_aio_attach_host_notifier_no_poll(vs->event_vq, s->ctx);
for (i = 0; i < vs->conf.num_queues; i++) {
virtio_queue_aio_attach_host_notifier(vs->cmd_vqs[i], s->ctx);

101
hw/scsi/virtio-scsi.c
View File

@ -29,6 +29,43 @@
#include "hw/virtio/virtio-access.h"
#include "trace.h"
typedef struct VirtIOSCSIReq {
/*
* Note:
* - fields up to resp_iov are initialized by virtio_scsi_init_req;
* - fields starting at vring are zeroed by virtio_scsi_init_req.
*/
VirtQueueElement elem;
VirtIOSCSI *dev;
VirtQueue *vq;
QEMUSGList qsgl;
QEMUIOVector resp_iov;
union {
/* Used for two-stage request submission */
QTAILQ_ENTRY(VirtIOSCSIReq) next;
/* Used for cancellation of request during TMFs */
int remaining;
};
SCSIRequest *sreq;
size_t resp_size;
enum SCSIXferMode mode;
union {
VirtIOSCSICmdResp cmd;
VirtIOSCSICtrlTMFResp tmf;
VirtIOSCSICtrlANResp an;
VirtIOSCSIEvent event;
} resp;
union {
VirtIOSCSICmdReq cmd;
VirtIOSCSICtrlTMFReq tmf;
VirtIOSCSICtrlANReq an;
} req;
} VirtIOSCSIReq;
static inline int virtio_scsi_get_lun(uint8_t *lun)
{
return ((lun[2] << 8) | lun[3]) & 0x3FFF;
@ -45,7 +82,7 @@ static inline SCSIDevice *virtio_scsi_device_get(VirtIOSCSI *s, uint8_t *lun)
return scsi_device_get(&s->bus, 0, lun[1], virtio_scsi_get_lun(lun));
}
void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
static void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
{
VirtIODevice *vdev = VIRTIO_DEVICE(s);
const size_t zero_skip =
@ -58,7 +95,7 @@ void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req)
memset((uint8_t *)req + zero_skip, 0, sizeof(*req) - zero_skip);
}
void virtio_scsi_free_req(VirtIOSCSIReq *req)
static void virtio_scsi_free_req(VirtIOSCSIReq *req)
{
qemu_iovec_destroy(&req->resp_iov);
qemu_sglist_destroy(&req->qsgl);
@ -460,28 +497,41 @@ static void virtio_scsi_handle_ctrl_req(VirtIOSCSI *s, VirtIOSCSIReq *req)
}
}
bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
static void virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq)
{
VirtIOSCSIReq *req;
bool progress = false;
while ((req = virtio_scsi_pop_req(s, vq))) {
progress = true;
virtio_scsi_handle_ctrl_req(s, req);
}
return progress;
}
/*
* If dataplane is configured but not yet started, do so now and return true on
* success.
*
* Dataplane is started by the core virtio code but virtqueue handler functions
* can also be invoked when a guest kicks before DRIVER_OK, so this helper
* function helps us deal with manually starting ioeventfd in that case.
*/
static bool virtio_scsi_defer_to_dataplane(VirtIOSCSI *s)
{
if (!s->ctx || s->dataplane_started) {
return false;
}
virtio_device_start_ioeventfd(&s->parent_obj.parent_obj);
return !s->dataplane_fenced;
}
static void virtio_scsi_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
if (s->ctx) {
virtio_device_start_ioeventfd(vdev);
if (!s->dataplane_fenced) {
return;
}
if (virtio_scsi_defer_to_dataplane(s)) {
return;
}
virtio_scsi_acquire(s);
virtio_scsi_handle_ctrl_vq(s, vq);
virtio_scsi_release(s);
@ -672,12 +722,11 @@ static void virtio_scsi_handle_cmd_req_submit(VirtIOSCSI *s, VirtIOSCSIReq *req)
scsi_req_unref(sreq);
}
bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
static void virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
{
VirtIOSCSIReq *req, *next;
int ret = 0;
bool suppress_notifications = virtio_queue_get_notification(vq);
bool progress = false;
QTAILQ_HEAD(, VirtIOSCSIReq) reqs = QTAILQ_HEAD_INITIALIZER(reqs);
@ -687,7 +736,6 @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
}
while ((req = virtio_scsi_pop_req(s, vq))) {
progress = true;
ret = virtio_scsi_handle_cmd_req_prepare(s, req);
if (!ret) {
QTAILQ_INSERT_TAIL(&reqs, req, next);
@ -712,7 +760,6 @@ bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq)
QTAILQ_FOREACH_SAFE(req, &reqs, next, next) {
virtio_scsi_handle_cmd_req_submit(s, req);
}
return progress;
}
static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
@ -720,12 +767,10 @@ static void virtio_scsi_handle_cmd(VirtIODevice *vdev, VirtQueue *vq)
/* use non-QOM casts in the data path */
VirtIOSCSI *s = (VirtIOSCSI *)vdev;
if (s->ctx && !s->dataplane_started) {
virtio_device_start_ioeventfd(vdev);
if (!s->dataplane_fenced) {
return;
}
if (virtio_scsi_defer_to_dataplane(s)) {
return;
}
virtio_scsi_acquire(s);
virtio_scsi_handle_cmd_vq(s, vq);
virtio_scsi_release(s);
@ -793,8 +838,8 @@ static void virtio_scsi_reset(VirtIODevice *vdev)
s->events_dropped = false;
}
void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
uint32_t event, uint32_t reason)
static void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
uint32_t event, uint32_t reason)
{
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(s);
VirtIOSCSIReq *req;
@ -842,25 +887,21 @@ void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
virtio_scsi_complete_req(req);
}
bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
static void virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq)
{
if (s->events_dropped) {
virtio_scsi_push_event(s, NULL, VIRTIO_SCSI_T_NO_EVENT, 0);
return true;
}
return false;
}
static void virtio_scsi_handle_event(VirtIODevice *vdev, VirtQueue *vq)
{
VirtIOSCSI *s = VIRTIO_SCSI(vdev);
if (s->ctx) {
virtio_device_start_ioeventfd(vdev);
if (!s->dataplane_fenced) {
return;
}
if (virtio_scsi_defer_to_dataplane(s)) {
return;
}
virtio_scsi_acquire(s);
virtio_scsi_handle_event_vq(s, vq);
virtio_scsi_release(s);

13
hw/virtio/virtio.c
View File

@ -3534,6 +3534,19 @@ void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx)
virtio_queue_host_notifier_aio_poll_end);
}
/*
* Same as virtio_queue_aio_attach_host_notifier() but without polling. Use
* this for rx virtqueues and similar cases where the virtqueue handler
* function does not pop all elements. When the virtqueue is left non-empty
* polling consumes CPU cycles and should not be used.
*/
void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ctx)
{
aio_set_event_notifier(ctx, &vq->host_notifier, true,
virtio_queue_host_notifier_read,
NULL, NULL);
}
void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx)
{
aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL, NULL);

10
include/block/aio.h
View File

@ -192,6 +192,8 @@ struct AioContext {
QSLIST_HEAD(, Coroutine) scheduled_coroutines;
QEMUBH *co_schedule_bh;
int thread_pool_min;
int thread_pool_max;
/* Thread pool for performing work and receiving completion callbacks.
* Has its own locking.
*/
@ -769,4 +771,12 @@ void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns,
void aio_context_set_aio_params(AioContext *ctx, int64_t max_batch,
Error **errp);
/**
* aio_context_set_thread_pool_params:
* @ctx: the aio context
* @min: min number of threads to have readily available in the thread pool
* @min: max number of threads the thread pool can contain
*/
void aio_context_set_thread_pool_params(AioContext *ctx, int64_t min,
int64_t max, Error **errp);
#endif

3
include/block/thread-pool.h
View File

@ -20,6 +20,8 @@
#include "block/block.h"
#define THREAD_POOL_MAX_THREADS_DEFAULT 64
typedef int ThreadPoolFunc(void *opaque);
typedef struct ThreadPool ThreadPool;
@ -33,5 +35,6 @@ BlockAIOCB *thread_pool_submit_aio(ThreadPool *pool,
int coroutine_fn thread_pool_submit_co(ThreadPool *pool,
ThreadPoolFunc *func, void *arg);
void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, void *arg);
void thread_pool_update_params(ThreadPool *pool, struct AioContext *ctx);
#endif

43
include/hw/virtio/virtio-scsi.h
View File

@ -92,42 +92,6 @@ struct VirtIOSCSI {
uint32_t host_features;
};
typedef struct VirtIOSCSIReq {
/* Note:
* - fields up to resp_iov are initialized by virtio_scsi_init_req;
* - fields starting at vring are zeroed by virtio_scsi_init_req.
* */
VirtQueueElement elem;
VirtIOSCSI *dev;
VirtQueue *vq;
QEMUSGList qsgl;
QEMUIOVector resp_iov;
union {
/* Used for two-stage request submission */
QTAILQ_ENTRY(VirtIOSCSIReq) next;
/* Used for cancellation of request during TMFs */
int remaining;
};
SCSIRequest *sreq;
size_t resp_size;
enum SCSIXferMode mode;
union {
VirtIOSCSICmdResp cmd;
VirtIOSCSICtrlTMFResp tmf;
VirtIOSCSICtrlANResp an;
VirtIOSCSIEvent event;
} resp;
union {
VirtIOSCSICmdReq cmd;
VirtIOSCSICtrlTMFReq tmf;
VirtIOSCSICtrlANReq an;
} req;
} VirtIOSCSIReq;
static inline void virtio_scsi_acquire(VirtIOSCSI *s)
{
if (s->ctx) {
@ -149,13 +113,6 @@ void virtio_scsi_common_realize(DeviceState *dev,
Error **errp);
void virtio_scsi_common_unrealize(DeviceState *dev);
bool virtio_scsi_handle_event_vq(VirtIOSCSI *s, VirtQueue *vq);
bool virtio_scsi_handle_cmd_vq(VirtIOSCSI *s, VirtQueue *vq);
bool virtio_scsi_handle_ctrl_vq(VirtIOSCSI *s, VirtQueue *vq);
void virtio_scsi_init_req(VirtIOSCSI *s, VirtQueue *vq, VirtIOSCSIReq *req);
void virtio_scsi_free_req(VirtIOSCSIReq *req);
void virtio_scsi_push_event(VirtIOSCSI *s, SCSIDevice *dev,
uint32_t event, uint32_t reason);
void virtio_scsi_dataplane_setup(VirtIOSCSI *s, Error **errp);
int virtio_scsi_dataplane_start(VirtIODevice *s);

1
include/hw/virtio/virtio.h
View File

@ -317,6 +317,7 @@ EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq);
void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled);
void virtio_queue_host_notifier_read(EventNotifier *n);
void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx);
void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ctx);
void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx);
VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector);
VirtQueue *virtio_vector_next_queue(VirtQueue *vq);

10
include/qemu/main-loop.h
View File

@ -26,9 +26,19 @@
#define QEMU_MAIN_LOOP_H
#include "block/aio.h"
#include "qom/object.h"
#include "sysemu/event-loop-base.h"
#define SIG_IPI SIGUSR1
#define TYPE_MAIN_LOOP "main-loop"
OBJECT_DECLARE_TYPE(MainLoop, MainLoopClass, MAIN_LOOP)
struct MainLoop {
EventLoopBase parent_obj;
};
typedef struct MainLoop MainLoop;
/**
* qemu_init_main_loop: Set up the process so that it can run the main loop.
*

41
include/sysemu/event-loop-base.h Normal file
View File

@ -0,0 +1,41 @@
/*
* QEMU event-loop backend
*
* Copyright (C) 2022 Red Hat Inc
*
* Authors:
* Nicolas Saenz Julienne <nsaenzju@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef QEMU_EVENT_LOOP_BASE_H
#define QEMU_EVENT_LOOP_BASE_H
#include "qom/object.h"
#include "block/aio.h"
#include "qemu/typedefs.h"
#define TYPE_EVENT_LOOP_BASE "event-loop-base"
OBJECT_DECLARE_TYPE(EventLoopBase, EventLoopBaseClass,
EVENT_LOOP_BASE)
struct EventLoopBaseClass {
ObjectClass parent_class;
void (*init)(EventLoopBase *base, Error **errp);
void (*update_params)(EventLoopBase *base, Error **errp);
bool (*can_be_deleted)(EventLoopBase *base);
};
struct EventLoopBase {
Object parent;
/* AioContext AIO engine parameters */
int64_t aio_max_batch;
/* AioContext thread pool parameters */
int64_t thread_pool_min;
int64_t thread_pool_max;
};
#endif

6
include/sysemu/iothread.h
View File

@ -17,11 +17,12 @@
#include "block/aio.h"
#include "qemu/thread.h"
#include "qom/object.h"
#include "sysemu/event-loop-base.h"
#define TYPE_IOTHREAD "iothread"
struct IOThread {
Object parent_obj;
EventLoopBase parent_obj;
QemuThread thread;
AioContext *ctx;
@ -37,9 +38,6 @@ struct IOThread {
int64_t poll_max_ns;
int64_t poll_grow;
int64_t poll_shrink;
/* AioContext AIO engine parameters */
int64_t aio_max_batch;
};
typedef struct IOThread IOThread;

68
iothread.c
View File

@ -17,6 +17,7 @@
#include "qemu/module.h"
#include "block/aio.h"
#include "block/block.h"
#include "sysemu/event-loop-base.h"
#include "sysemu/iothread.h"
#include "qapi/error.h"
#include "qapi/qapi-commands-misc.h"
@ -152,10 +153,15 @@ static void iothread_init_gcontext(IOThread *iothread)
iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE);
}
static void iothread_set_aio_context_params(IOThread *iothread, Error **errp)
static void iothread_set_aio_context_params(EventLoopBase *base, Error **errp)
{
IOThread *iothread = IOTHREAD(base);
ERRP_GUARD();
if (!iothread->ctx) {
return;
}
aio_context_set_poll_params(iothread->ctx,
iothread->poll_max_ns,
iothread->poll_grow,
@ -166,14 +172,18 @@ static void iothread_set_aio_context_params(IOThread *iothread, Error **errp)
}
aio_context_set_aio_params(iothread->ctx,
iothread->aio_max_batch,
iothread->parent_obj.aio_max_batch,
errp);
aio_context_set_thread_pool_params(iothread->ctx, base->thread_pool_min,
base->thread_pool_max, errp);
}
static void iothread_complete(UserCreatable *obj, Error **errp)
static void iothread_init(EventLoopBase *base, Error **errp)
{
Error *local_error = NULL;
IOThread *iothread = IOTHREAD(obj);
IOThread *iothread = IOTHREAD(base);
char *thread_name;
iothread->stopping = false;
@ -189,7 +199,7 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
*/
iothread_init_gcontext(iothread);
iothread_set_aio_context_params(iothread, &local_error);
iothread_set_aio_context_params(base, &local_error);
if (local_error) {
error_propagate(errp, local_error);
aio_context_unref(iothread->ctx);
@ -201,7 +211,7 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
* to inherit.
*/
thread_name = g_strdup_printf("IO %s",
object_get_canonical_path_component(OBJECT(obj)));
object_get_canonical_path_component(OBJECT(base)));
qemu_thread_create(&iothread->thread, thread_name, iothread_run,
iothread, QEMU_THREAD_JOINABLE);
g_free(thread_name);
@ -226,9 +236,6 @@ static IOThreadParamInfo poll_grow_info = {
static IOThreadParamInfo poll_shrink_info = {
"poll-shrink", offsetof(IOThread, poll_shrink),
};
static IOThreadParamInfo aio_max_batch_info = {
"aio-max-batch", offsetof(IOThread, aio_max_batch),
};
static void iothread_get_param(Object *obj, Visitor *v,
const char *name, IOThreadParamInfo *info, Error **errp)
@ -288,35 +295,12 @@ static void iothread_set_poll_param(Object *obj, Visitor *v,
}
}
static void iothread_get_aio_param(Object *obj, Visitor *v,
const char *name, void *opaque, Error **errp)
{
IOThreadParamInfo *info = opaque;
iothread_get_param(obj, v, name, info, errp);
}
static void iothread_set_aio_param(Object *obj, Visitor *v,
const char *name, void *opaque, Error **errp)
{
IOThread *iothread = IOTHREAD(obj);
IOThreadParamInfo *info = opaque;
if (!iothread_set_param(obj, v, name, info, errp)) {
return;
}
if (iothread->ctx) {
aio_context_set_aio_params(iothread->ctx,
iothread->aio_max_batch,
errp);
}
}
static void iothread_class_init(ObjectClass *klass, void *class_data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
ucc->complete = iothread_complete;
EventLoopBaseClass *bc = EVENT_LOOP_BASE_CLASS(klass);
bc->init = iothread_init;
bc->update_params = iothread_set_aio_context_params;
object_class_property_add(klass, "poll-max-ns", "int",
iothread_get_poll_param,
@ -330,23 +314,15 @@ static void iothread_class_init(ObjectClass *klass, void *class_data)
iothread_get_poll_param,
iothread_set_poll_param,
NULL, &poll_shrink_info);
object_class_property_add(klass, "aio-max-batch", "int",
iothread_get_aio_param,
iothread_set_aio_param,
NULL, &aio_max_batch_info);
}
static const TypeInfo iothread_info = {
.name = TYPE_IOTHREAD,
.parent = TYPE_OBJECT,
.parent = TYPE_EVENT_LOOP_BASE,
.class_init = iothread_class_init,
.instance_size = sizeof(IOThread),
.instance_init = iothread_instance_init,
.instance_finalize = iothread_instance_finalize,
.interfaces = (InterfaceInfo[]) {
{TYPE_USER_CREATABLE},
{}
},
};
static void iothread_register_types(void)
@ -383,7 +359,7 @@ static int query_one_iothread(Object *object, void *opaque)
info->poll_max_ns = iothread->poll_max_ns;
info->poll_grow = iothread->poll_grow;
info->poll_shrink = iothread->poll_shrink;
info->aio_max_batch = iothread->aio_max_batch;
info->aio_max_batch = iothread->parent_obj.aio_max_batch;
QAPI_LIST_APPEND(*tail, info);
return 0;

26
meson.build
View File

@ -3025,6 +3025,7 @@ subdir('qom')
subdir('authz')
subdir('crypto')
subdir('ui')
subdir('hw')
if enable_modules
@ -3032,6 +3033,18 @@ if enable_modules
modulecommon = declare_dependency(link_whole: libmodulecommon, compile_args: '-DBUILD_DSO')
endif
qom_ss = qom_ss.apply(config_host, strict: false)
libqom = static_library('qom', qom_ss.sources() + genh,
dependencies: [qom_ss.dependencies()],
name_suffix: 'fa')
qom = declare_dependency(link_whole: libqom)
event_loop_base = files('event-loop-base.c')
event_loop_base = static_library('event-loop-base', sources: event_loop_base + genh,
build_by_default: true)
event_loop_base = declare_dependency(link_whole: event_loop_base,
dependencies: [qom])
stub_ss = stub_ss.apply(config_all, strict: false)
util_ss.add_all(trace_ss)
@ -3040,7 +3053,8 @@ libqemuutil = static_library('qemuutil',
sources: util_ss.sources() + stub_ss.sources() + genh,
dependencies: [util_ss.dependencies(), libm, threads, glib, socket, malloc, pixman])
qemuutil = declare_dependency(link_with: libqemuutil,
sources: genh + version_res)
sources: genh + version_res,
dependencies: [event_loop_base])
if have_system or have_user
decodetree = generator(find_program('scripts/decodetree.py'),
@ -3118,7 +3132,6 @@ subdir('monitor')
subdir('net')
subdir('replay')
subdir('semihosting')
subdir('hw')
subdir('tcg')
subdir('fpu')
subdir('accel')
@ -3243,13 +3256,6 @@ qemu_syms = custom_target('qemu.syms', output: 'qemu.syms',
capture: true,
command: [undefsym, nm, '@INPUT@'])
qom_ss = qom_ss.apply(config_host, strict: false)
libqom = static_library('qom', qom_ss.sources() + genh,
dependencies: [qom_ss.dependencies()],
name_suffix: 'fa')
qom = declare_dependency(link_whole: libqom)
authz_ss = authz_ss.apply(config_host, strict: false)
libauthz = static_library('authz', authz_ss.sources() + genh,
dependencies: [authz_ss.dependencies()],
@ -3302,7 +3308,7 @@ libblockdev = static_library('blockdev', blockdev_ss.sources() + genh,
build_by_default: false)
blockdev = declare_dependency(link_whole: [libblockdev],
dependencies: [block])
dependencies: [block, event_loop_base])
qmp_ss = qmp_ss.apply(config_host, strict: false)
libqmp = static_library('qmp', qmp_ss.sources() + genh,

43
qapi/qom.json
View File

@ -499,6 +499,28 @@
'*repeat': 'bool',
'*grab-toggle': 'GrabToggleKeys' } }
##
# @EventLoopBaseProperties:
#
# Common properties for event loops
#
# @aio-max-batch: maximum number of requests in a batch for the AIO engine,
# 0 means that the engine will use its default.
# (default: 0)
#
# @thread-pool-min: minimum number of threads reserved in the thread pool
# (default:0)
#
# @thread-pool-max: maximum number of threads the thread pool can contain
# (default:64)
#
# Since: 7.1
##
{ 'struct': 'EventLoopBaseProperties',
'data': { '*aio-max-batch': 'int',
'*thread-pool-min': 'int',
'*thread-pool-max': 'int' } }
##
# @IothreadProperties:
#
@ -516,17 +538,26 @@
# algorithm detects it is spending too long polling without
# encountering events. 0 selects a default behaviour (default: 0)
#
# @aio-max-batch: maximum number of requests in a batch for the AIO engine,
# 0 means that the engine will use its default
# (default:0, since 6.1)
# The @aio-max-batch option is available since 6.1.
#
# Since: 2.0
##
{ 'struct': 'IothreadProperties',
'base': 'EventLoopBaseProperties',
'data': { '*poll-max-ns': 'int',
'*poll-grow': 'int',
'*poll-shrink': 'int',
'*aio-max-batch': 'int' } }
'*poll-shrink': 'int' } }
##
# @MainLoopProperties:
#
# Properties for the main-loop object.
#
# Since: 7.1
##
{ 'struct': 'MainLoopProperties',
'base': 'EventLoopBaseProperties',
'data': {} }
##
# @MemoryBackendProperties:
@ -818,6 +849,7 @@
{ 'name': 'input-linux',
'if': 'CONFIG_LINUX' },
'iothread',
'main-loop',
{ 'name': 'memory-backend-epc',
'if': 'CONFIG_LINUX' },
'memory-backend-file',
@ -883,6 +915,7 @@
'input-linux': { 'type': 'InputLinuxProperties',
'if': 'CONFIG_LINUX' },
'iothread': 'IothreadProperties',
'main-loop': 'MainLoopProperties',
'memory-backend-epc': { 'type': 'MemoryBackendEpcProperties',
'if': 'CONFIG_LINUX' },
'memory-backend-file': 'MemoryBackendFileProperties',

1
util/aio-posix.c
View File

@ -15,6 +15,7 @@
#include "qemu/osdep.h"
#include "block/block.h"
#include "block/thread-pool.h"
#include "qemu/main-loop.h"
#include "qemu/rcu.h"
#include "qemu/rcu_queue.h"

20
util/async.c
View File

@ -563,6 +563,9 @@ AioContext *aio_context_new(Error **errp)
ctx->aio_max_batch = 0;
ctx->thread_pool_min = 0;
ctx->thread_pool_max = THREAD_POOL_MAX_THREADS_DEFAULT;
return ctx;
fail:
g_source_destroy(&ctx->source);
@ -696,3 +699,20 @@ void qemu_set_current_aio_context(AioContext *ctx)
assert(!get_my_aiocontext());
set_my_aiocontext(ctx);
}
void aio_context_set_thread_pool_params(AioContext *ctx, int64_t min,
int64_t max, Error **errp)
{
if (min > max || !max || min > INT_MAX || max > INT_MAX) {
error_setg(errp, "bad thread-pool-min/thread-pool-max values");
return;
}
ctx->thread_pool_min = min;
ctx->thread_pool_max = max;
if (ctx->thread_pool) {
thread_pool_update_params(ctx->thread_pool, ctx);
}
}

65
util/main-loop.c
View File

@ -30,9 +30,11 @@
#include "sysemu/replay.h"
#include "qemu/main-loop.h"
#include "block/aio.h"
#include "block/thread-pool.h"
#include "qemu/error-report.h"
#include "qemu/queue.h"
#include "qemu/compiler.h"
#include "qom/object.h"
#ifndef _WIN32
#include <sys/wait.h>
@ -184,6 +186,69 @@ int qemu_init_main_loop(Error **errp)
return 0;
}
static void main_loop_update_params(EventLoopBase *base, Error **errp)
{
ERRP_GUARD();
if (!qemu_aio_context) {
error_setg(errp, "qemu aio context not ready");
return;
}
aio_context_set_aio_params(qemu_aio_context, base->aio_max_batch, errp);
if (*errp) {
return;
}
aio_context_set_thread_pool_params(qemu_aio_context, base->thread_pool_min,
base->thread_pool_max, errp);
}
MainLoop *mloop;
static void main_loop_init(EventLoopBase *base, Error **errp)
{
MainLoop *m = MAIN_LOOP(base);
if (mloop) {
error_setg(errp, "only one main-loop instance allowed");
return;
}
main_loop_update_params(base, errp);
mloop = m;
return;
}
static bool main_loop_can_be_deleted(EventLoopBase *base)
{
return false;
}
static void main_loop_class_init(ObjectClass *oc, void *class_data)
{
EventLoopBaseClass *bc = EVENT_LOOP_BASE_CLASS(oc);
bc->init = main_loop_init;
bc->update_params = main_loop_update_params;
bc->can_be_deleted = main_loop_can_be_deleted;
}
static const TypeInfo main_loop_info = {
.name = TYPE_MAIN_LOOP,
.parent = TYPE_EVENT_LOOP_BASE,
.class_init = main_loop_class_init,
.instance_size = sizeof(MainLoop),
};
static void main_loop_register_types(void)
{
type_register_static(&main_loop_info);
}
type_init(main_loop_register_types)
static int max_priority;
#ifndef _WIN32

55
util/thread-pool.c
View File

@ -58,7 +58,6 @@ struct ThreadPool {
QemuMutex lock;
QemuCond worker_stopped;
QemuSemaphore sem;
int max_threads;
QEMUBH *new_thread_bh;
/* The following variables are only accessed from one AioContext. */
@ -71,8 +70,27 @@ struct ThreadPool {
int new_threads; /* backlog of threads we need to create */
int pending_threads; /* threads created but not running yet */
bool stopping;
int min_threads;
int max_threads;
};
static inline bool back_to_sleep(ThreadPool *pool, int ret)
{
/*
* The semaphore timed out, we should exit the loop except when:
* - There is work to do, we raced with the signal.
* - The max threads threshold just changed, we raced with the signal.
* - The thread pool forces a minimum number of readily available threads.
*/
if (ret == -1 && (!QTAILQ_EMPTY(&pool->request_list) ||
pool->cur_threads > pool->max_threads ||
pool->cur_threads <= pool->min_threads)) {
return true;
}
return false;
}
static void *worker_thread(void *opaque)
{
ThreadPool *pool = opaque;
@ -91,8 +109,9 @@ static void *worker_thread(void *opaque)
ret = qemu_sem_timedwait(&pool->sem, 10000);
qemu_mutex_lock(&pool->lock);
pool->idle_threads--;
} while (ret == -1 && !QTAILQ_EMPTY(&pool->request_list));
if (ret == -1 || pool->stopping) {
} while (back_to_sleep(pool, ret));
if (ret == -1 || pool->stopping ||
pool->cur_threads > pool->max_threads) {
break;
}
@ -294,6 +313,33 @@ void thread_pool_submit(ThreadPool *pool, ThreadPoolFunc *func, void *arg)
thread_pool_submit_aio(pool, func, arg, NULL, NULL);
}
void thread_pool_update_params(ThreadPool *pool, AioContext *ctx)
{
qemu_mutex_lock(&pool->lock);
pool->min_threads = ctx->thread_pool_min;
pool->max_threads = ctx->thread_pool_max;
/*
* We either have to:
* - Increase the number available of threads until over the min_threads
* threshold.
* - Decrease the number of available threads until under the max_threads
* threshold.
* - Do nothing. The current number of threads fall in between the min and
* max thresholds. We'll let the pool manage itself.
*/
for (int i = pool->cur_threads; i < pool->min_threads; i++) {
spawn_thread(pool);
}
for (int i = pool->cur_threads; i > pool->max_threads; i--) {
qemu_sem_post(&pool->sem);
}
qemu_mutex_unlock(&pool->lock);
}
static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx)
{
if (!ctx) {
@ -306,11 +352,12 @@ static void thread_pool_init_one(ThreadPool *pool, AioContext *ctx)
qemu_mutex_init(&pool->lock);
qemu_cond_init(&pool->worker_stopped);
qemu_sem_init(&pool->sem, 0);
pool->max_threads = 64;
pool->new_thread_bh = aio_bh_new(ctx, spawn_thread_bh_fn, pool);
QLIST_INIT(&pool->head);
QTAILQ_INIT(&pool->request_list);
thread_pool_update_params(pool, ctx);
}
ThreadPool *thread_pool_new(AioContext *ctx)