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authorPaolo Bonzini <pbonzini@redhat.com>2017-02-13 14:52:18 +0100
committerStefan Hajnoczi <stefanha@redhat.com>2017-02-21 11:14:07 +0000
commitc2b38b277a7882a592f4f2ec955084b2b756daaa (patch)
treeeefb45723912dab21c32f9d4d6bec65e4698d2fb /async.c
parent56f9e46b841c7be478ca038d8d4085d776ab4b0d (diff)
downloadqemu-arm-c2b38b277a7882a592f4f2ec955084b2b756daaa.tar.gz
block: move AioContext, QEMUTimer, main-loop to libqemuutil
AioContext is fairly self contained, the only dependency is QEMUTimer but that in turn doesn't need anything else. So move them out of block-obj-y to avoid introducing a dependency from io/ to block-obj-y. main-loop and its dependency iohandler also need to be moved, because later in this series io/ will call iohandler_get_aio_context. [Changed copyright "the QEMU team" to "other QEMU contributors" as suggested by Daniel Berrange and agreed by Paolo. --Stefan] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Message-id: 20170213135235.12274-2-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'async.c')
-rw-r--r--async.c422
1 files changed, 0 insertions, 422 deletions
diff --git a/async.c b/async.c
deleted file mode 100644
index 0d218ab0e0..0000000000
--- a/async.c
+++ /dev/null
@@ -1,422 +0,0 @@
-/*
- * 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;
-};
-
-void aio_bh_schedule_oneshot(AioContext *ctx, QEMUBHFunc *cb, void *opaque)
-{
- QEMUBH *bh;
- bh = g_new(QEMUBH, 1);
- *bh = (QEMUBH){
- .ctx = ctx,
- .cb = cb,
- .opaque = opaque,
- };
- qemu_lockcnt_lock(&ctx->list_lock);
- bh->next = ctx->first_bh;
- bh->scheduled = 1;
- bh->deleted = 1;
- /* Make sure that the members are ready before putting bh into list */
- smp_wmb();
- ctx->first_bh = bh;
- qemu_lockcnt_unlock(&ctx->list_lock);
- aio_notify(ctx);
-}
-
-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_lockcnt_lock(&ctx->list_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_lockcnt_unlock(&ctx->list_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;
- bool deleted = false;
-
- qemu_lockcnt_inc(&ctx->list_lock);
-
- ret = 0;
- for (bh = atomic_rcu_read(&ctx->first_bh); bh; bh = next) {
- next = atomic_rcu_read(&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 (atomic_xchg(&bh->scheduled, 0)) {
- /* Idle BHs don't count as progress */
- if (!bh->idle) {
- ret = 1;
- }
- bh->idle = 0;
- aio_bh_call(bh);
- }
- if (bh->deleted) {
- deleted = true;
- }
- }
-
- /* remove deleted bhs */
- if (!deleted) {
- qemu_lockcnt_dec(&ctx->list_lock);
- return ret;
- }
-
- if (qemu_lockcnt_dec_and_lock(&ctx->list_lock)) {
- bhp = &ctx->first_bh;
- while (*bhp) {
- bh = *bhp;
- if (bh->deleted && !bh->scheduled) {
- *bhp = bh->next;
- g_free(bh);
- } else {
- bhp = &bh->next;
- }
- }
- qemu_lockcnt_unlock(&ctx->list_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 = atomic_rcu_read(&ctx->first_bh); bh;
- bh = atomic_rcu_read(&bh->next)) {
- if (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->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, true);
- return true;
-}
-
-static void
-aio_ctx_finalize(GSource *source)
-{
- AioContext *ctx = (AioContext *) source;
-
- 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_lockcnt_lock(&ctx->list_lock);
- assert(!qemu_lockcnt_count(&ctx->list_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_lockcnt_unlock(&ctx->list_lock);
-
- aio_set_event_notifier(ctx, &ctx->notifier, false, NULL, NULL);
- event_notifier_cleanup(&ctx->notifier);
- qemu_rec_mutex_destroy(&ctx->lock);
- qemu_lockcnt_destroy(&ctx->list_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 event_notifier_dummy_cb(EventNotifier *e)
-{
-}
-
-/* Returns true if aio_notify() was called (e.g. a BH was scheduled) */
-static bool event_notifier_poll(void *opaque)
-{
- EventNotifier *e = opaque;
- AioContext *ctx = container_of(e, AioContext, notifier);
-
- return atomic_read(&ctx->notified);
-}
-
-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);
- qemu_lockcnt_init(&ctx->list_lock);
- aio_set_event_notifier(ctx, &ctx->notifier,
- false,
- (EventNotifierHandler *)
- event_notifier_dummy_cb,
- event_notifier_poll);
-#ifdef CONFIG_LINUX_AIO
- ctx->linux_aio = NULL;
-#endif
- ctx->thread_pool = NULL;
- qemu_rec_mutex_init(&ctx->lock);
- timerlistgroup_init(&ctx->tlg, aio_timerlist_notify, ctx);
-
- ctx->poll_ns = 0;
- ctx->poll_max_ns = 0;
- ctx->poll_grow = 0;
- ctx->poll_shrink = 0;
-
- 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)
-{
- qemu_rec_mutex_lock(&ctx->lock);
-}
-
-void aio_context_release(AioContext *ctx)
-{
- qemu_rec_mutex_unlock(&ctx->lock);
-}