mirror of
https://github.com/xemu-project/xemu.git
synced 2024-12-12 14:05:56 +00:00
7e00346505
Parameter **errp of aio_context_setup() is useless, remove it and clean up the related code. Cc: Stefan Hajnoczi <stefanha@redhat.com> Cc: Fam Zheng <famz@redhat.com> Cc: Eric Blake <eblake@redhat.com> Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com> Reviewed-by: Eric Blake <eblake@redhat.com> Message-id: 1468578524-23433-1-git-send-email-caoj.fnst@cn.fujitsu.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
399 lines
9.8 KiB
C
399 lines
9.8 KiB
C
/*
|
|
* QEMU System Emulator
|
|
*
|
|
* Copyright (c) 2003-2008 Fabrice Bellard
|
|
*
|
|
* Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
* of this software and associated documentation files (the "Software"), to deal
|
|
* in the Software without restriction, including without limitation the rights
|
|
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
* copies of the Software, and to permit persons to whom the Software is
|
|
* furnished to do so, subject to the following conditions:
|
|
*
|
|
* The above copyright notice and this permission notice shall be included in
|
|
* all copies or substantial portions of the Software.
|
|
*
|
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
|
|
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
* THE SOFTWARE.
|
|
*/
|
|
|
|
#include "qemu/osdep.h"
|
|
#include "qapi/error.h"
|
|
#include "qemu-common.h"
|
|
#include "block/aio.h"
|
|
#include "block/thread-pool.h"
|
|
#include "qemu/main-loop.h"
|
|
#include "qemu/atomic.h"
|
|
#include "block/raw-aio.h"
|
|
|
|
/***********************************************************/
|
|
/* bottom halves (can be seen as timers which expire ASAP) */
|
|
|
|
struct QEMUBH {
|
|
AioContext *ctx;
|
|
QEMUBHFunc *cb;
|
|
void *opaque;
|
|
QEMUBH *next;
|
|
bool scheduled;
|
|
bool idle;
|
|
bool deleted;
|
|
};
|
|
|
|
QEMUBH *aio_bh_new(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
|
|
{
|
|
QEMUBH *bh;
|
|
bh = g_new(QEMUBH, 1);
|
|
*bh = (QEMUBH){
|
|
.ctx = ctx,
|
|
.cb = cb,
|
|
.opaque = opaque,
|
|
};
|
|
qemu_mutex_lock(&ctx->bh_lock);
|
|
bh->next = ctx->first_bh;
|
|
/* Make sure that the members are ready before putting bh into list */
|
|
smp_wmb();
|
|
ctx->first_bh = bh;
|
|
qemu_mutex_unlock(&ctx->bh_lock);
|
|
return bh;
|
|
}
|
|
|
|
void aio_bh_call(QEMUBH *bh)
|
|
{
|
|
bh->cb(bh->opaque);
|
|
}
|
|
|
|
/* Multiple occurrences of aio_bh_poll cannot be called concurrently */
|
|
int aio_bh_poll(AioContext *ctx)
|
|
{
|
|
QEMUBH *bh, **bhp, *next;
|
|
int ret;
|
|
|
|
ctx->walking_bh++;
|
|
|
|
ret = 0;
|
|
for (bh = ctx->first_bh; bh; bh = next) {
|
|
/* Make sure that fetching bh happens before accessing its members */
|
|
smp_read_barrier_depends();
|
|
next = bh->next;
|
|
/* The atomic_xchg is paired with the one in qemu_bh_schedule. The
|
|
* implicit memory barrier ensures that the callback sees all writes
|
|
* done by the scheduling thread. It also ensures that the scheduling
|
|
* thread sees the zero before bh->cb has run, and thus will call
|
|
* aio_notify again if necessary.
|
|
*/
|
|
if (!bh->deleted && atomic_xchg(&bh->scheduled, 0)) {
|
|
/* Idle BHs and the notify BH don't count as progress */
|
|
if (!bh->idle && bh != ctx->notify_dummy_bh) {
|
|
ret = 1;
|
|
}
|
|
bh->idle = 0;
|
|
aio_bh_call(bh);
|
|
}
|
|
}
|
|
|
|
ctx->walking_bh--;
|
|
|
|
/* remove deleted bhs */
|
|
if (!ctx->walking_bh) {
|
|
qemu_mutex_lock(&ctx->bh_lock);
|
|
bhp = &ctx->first_bh;
|
|
while (*bhp) {
|
|
bh = *bhp;
|
|
if (bh->deleted) {
|
|
*bhp = bh->next;
|
|
g_free(bh);
|
|
} else {
|
|
bhp = &bh->next;
|
|
}
|
|
}
|
|
qemu_mutex_unlock(&ctx->bh_lock);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void qemu_bh_schedule_idle(QEMUBH *bh)
|
|
{
|
|
bh->idle = 1;
|
|
/* Make sure that idle & any writes needed by the callback are done
|
|
* before the locations are read in the aio_bh_poll.
|
|
*/
|
|
atomic_mb_set(&bh->scheduled, 1);
|
|
}
|
|
|
|
void qemu_bh_schedule(QEMUBH *bh)
|
|
{
|
|
AioContext *ctx;
|
|
|
|
ctx = bh->ctx;
|
|
bh->idle = 0;
|
|
/* The memory barrier implicit in atomic_xchg makes sure that:
|
|
* 1. idle & any writes needed by the callback are done before the
|
|
* locations are read in the aio_bh_poll.
|
|
* 2. ctx is loaded before scheduled is set and the callback has a chance
|
|
* to execute.
|
|
*/
|
|
if (atomic_xchg(&bh->scheduled, 1) == 0) {
|
|
aio_notify(ctx);
|
|
}
|
|
}
|
|
|
|
|
|
/* This func is async.
|
|
*/
|
|
void qemu_bh_cancel(QEMUBH *bh)
|
|
{
|
|
bh->scheduled = 0;
|
|
}
|
|
|
|
/* This func is async.The bottom half will do the delete action at the finial
|
|
* end.
|
|
*/
|
|
void qemu_bh_delete(QEMUBH *bh)
|
|
{
|
|
bh->scheduled = 0;
|
|
bh->deleted = 1;
|
|
}
|
|
|
|
int64_t
|
|
aio_compute_timeout(AioContext *ctx)
|
|
{
|
|
int64_t deadline;
|
|
int timeout = -1;
|
|
QEMUBH *bh;
|
|
|
|
for (bh = ctx->first_bh; bh; bh = bh->next) {
|
|
if (!bh->deleted && bh->scheduled) {
|
|
if (bh->idle) {
|
|
/* idle bottom halves will be polled at least
|
|
* every 10ms */
|
|
timeout = 10000000;
|
|
} else {
|
|
/* non-idle bottom halves will be executed
|
|
* immediately */
|
|
return 0;
|
|
}
|
|
}
|
|
}
|
|
|
|
deadline = timerlistgroup_deadline_ns(&ctx->tlg);
|
|
if (deadline == 0) {
|
|
return 0;
|
|
} else {
|
|
return qemu_soonest_timeout(timeout, deadline);
|
|
}
|
|
}
|
|
|
|
static gboolean
|
|
aio_ctx_prepare(GSource *source, gint *timeout)
|
|
{
|
|
AioContext *ctx = (AioContext *) source;
|
|
|
|
atomic_or(&ctx->notify_me, 1);
|
|
|
|
/* We assume there is no timeout already supplied */
|
|
*timeout = qemu_timeout_ns_to_ms(aio_compute_timeout(ctx));
|
|
|
|
if (aio_prepare(ctx)) {
|
|
*timeout = 0;
|
|
}
|
|
|
|
return *timeout == 0;
|
|
}
|
|
|
|
static gboolean
|
|
aio_ctx_check(GSource *source)
|
|
{
|
|
AioContext *ctx = (AioContext *) source;
|
|
QEMUBH *bh;
|
|
|
|
atomic_and(&ctx->notify_me, ~1);
|
|
aio_notify_accept(ctx);
|
|
|
|
for (bh = ctx->first_bh; bh; bh = bh->next) {
|
|
if (!bh->deleted && bh->scheduled) {
|
|
return true;
|
|
}
|
|
}
|
|
return aio_pending(ctx) || (timerlistgroup_deadline_ns(&ctx->tlg) == 0);
|
|
}
|
|
|
|
static gboolean
|
|
aio_ctx_dispatch(GSource *source,
|
|
GSourceFunc callback,
|
|
gpointer user_data)
|
|
{
|
|
AioContext *ctx = (AioContext *) source;
|
|
|
|
assert(callback == NULL);
|
|
aio_dispatch(ctx);
|
|
return true;
|
|
}
|
|
|
|
static void
|
|
aio_ctx_finalize(GSource *source)
|
|
{
|
|
AioContext *ctx = (AioContext *) source;
|
|
|
|
qemu_bh_delete(ctx->notify_dummy_bh);
|
|
thread_pool_free(ctx->thread_pool);
|
|
|
|
#ifdef CONFIG_LINUX_AIO
|
|
if (ctx->linux_aio) {
|
|
laio_detach_aio_context(ctx->linux_aio, ctx);
|
|
laio_cleanup(ctx->linux_aio);
|
|
ctx->linux_aio = NULL;
|
|
}
|
|
#endif
|
|
|
|
qemu_mutex_lock(&ctx->bh_lock);
|
|
while (ctx->first_bh) {
|
|
QEMUBH *next = ctx->first_bh->next;
|
|
|
|
/* qemu_bh_delete() must have been called on BHs in this AioContext */
|
|
assert(ctx->first_bh->deleted);
|
|
|
|
g_free(ctx->first_bh);
|
|
ctx->first_bh = next;
|
|
}
|
|
qemu_mutex_unlock(&ctx->bh_lock);
|
|
|
|
aio_set_event_notifier(ctx, &ctx->notifier, false, NULL);
|
|
event_notifier_cleanup(&ctx->notifier);
|
|
rfifolock_destroy(&ctx->lock);
|
|
qemu_mutex_destroy(&ctx->bh_lock);
|
|
timerlistgroup_deinit(&ctx->tlg);
|
|
}
|
|
|
|
static GSourceFuncs aio_source_funcs = {
|
|
aio_ctx_prepare,
|
|
aio_ctx_check,
|
|
aio_ctx_dispatch,
|
|
aio_ctx_finalize
|
|
};
|
|
|
|
GSource *aio_get_g_source(AioContext *ctx)
|
|
{
|
|
g_source_ref(&ctx->source);
|
|
return &ctx->source;
|
|
}
|
|
|
|
ThreadPool *aio_get_thread_pool(AioContext *ctx)
|
|
{
|
|
if (!ctx->thread_pool) {
|
|
ctx->thread_pool = thread_pool_new(ctx);
|
|
}
|
|
return ctx->thread_pool;
|
|
}
|
|
|
|
#ifdef CONFIG_LINUX_AIO
|
|
LinuxAioState *aio_get_linux_aio(AioContext *ctx)
|
|
{
|
|
if (!ctx->linux_aio) {
|
|
ctx->linux_aio = laio_init();
|
|
laio_attach_aio_context(ctx->linux_aio, ctx);
|
|
}
|
|
return ctx->linux_aio;
|
|
}
|
|
#endif
|
|
|
|
void aio_notify(AioContext *ctx)
|
|
{
|
|
/* Write e.g. bh->scheduled before reading ctx->notify_me. Pairs
|
|
* with atomic_or in aio_ctx_prepare or atomic_add in aio_poll.
|
|
*/
|
|
smp_mb();
|
|
if (ctx->notify_me) {
|
|
event_notifier_set(&ctx->notifier);
|
|
atomic_mb_set(&ctx->notified, true);
|
|
}
|
|
}
|
|
|
|
void aio_notify_accept(AioContext *ctx)
|
|
{
|
|
if (atomic_xchg(&ctx->notified, false)) {
|
|
event_notifier_test_and_clear(&ctx->notifier);
|
|
}
|
|
}
|
|
|
|
static void aio_timerlist_notify(void *opaque)
|
|
{
|
|
aio_notify(opaque);
|
|
}
|
|
|
|
static void aio_rfifolock_cb(void *opaque)
|
|
{
|
|
AioContext *ctx = opaque;
|
|
|
|
/* Kick owner thread in case they are blocked in aio_poll() */
|
|
qemu_bh_schedule(ctx->notify_dummy_bh);
|
|
}
|
|
|
|
static void notify_dummy_bh(void *opaque)
|
|
{
|
|
/* Do nothing, we were invoked just to force the event loop to iterate */
|
|
}
|
|
|
|
static void event_notifier_dummy_cb(EventNotifier *e)
|
|
{
|
|
}
|
|
|
|
AioContext *aio_context_new(Error **errp)
|
|
{
|
|
int ret;
|
|
AioContext *ctx;
|
|
|
|
ctx = (AioContext *) g_source_new(&aio_source_funcs, sizeof(AioContext));
|
|
aio_context_setup(ctx);
|
|
|
|
ret = event_notifier_init(&ctx->notifier, false);
|
|
if (ret < 0) {
|
|
error_setg_errno(errp, -ret, "Failed to initialize event notifier");
|
|
goto fail;
|
|
}
|
|
g_source_set_can_recurse(&ctx->source, true);
|
|
aio_set_event_notifier(ctx, &ctx->notifier,
|
|
false,
|
|
(EventNotifierHandler *)
|
|
event_notifier_dummy_cb);
|
|
#ifdef CONFIG_LINUX_AIO
|
|
ctx->linux_aio = NULL;
|
|
#endif
|
|
ctx->thread_pool = NULL;
|
|
qemu_mutex_init(&ctx->bh_lock);
|
|
rfifolock_init(&ctx->lock, aio_rfifolock_cb, ctx);
|
|
timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
|
|
|
|
ctx->notify_dummy_bh = aio_bh_new(ctx, notify_dummy_bh, NULL);
|
|
|
|
return ctx;
|
|
fail:
|
|
g_source_destroy(&ctx->source);
|
|
return NULL;
|
|
}
|
|
|
|
void aio_context_ref(AioContext *ctx)
|
|
{
|
|
g_source_ref(&ctx->source);
|
|
}
|
|
|
|
void aio_context_unref(AioContext *ctx)
|
|
{
|
|
g_source_unref(&ctx->source);
|
|
}
|
|
|
|
void aio_context_acquire(AioContext *ctx)
|
|
{
|
|
rfifolock_lock(&ctx->lock);
|
|
}
|
|
|
|
void aio_context_release(AioContext *ctx)
|
|
{
|
|
rfifolock_unlock(&ctx->lock);
|
|
}
|