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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 /util/aio-posix.c
parent56f9e46b841c7be478ca038d8d4085d776ab4b0d (diff)
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 'util/aio-posix.c')
-rw-r--r--util/aio-posix.c758
1 files changed, 758 insertions, 0 deletions
diff --git a/util/aio-posix.c b/util/aio-posix.c
new file mode 100644
index 0000000000..a8d7090bd8
--- /dev/null
+++ b/util/aio-posix.c
@@ -0,0 +1,758 @@
+/*
+ * QEMU aio implementation
+ *
+ * Copyright IBM, Corp. 2008
+ *
+ * Authors:
+ * Anthony Liguori <aliguori@us.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2. See
+ * the COPYING file in the top-level directory.
+ *
+ * Contributions after 2012-01-13 are licensed under the terms of the
+ * GNU GPL, version 2 or (at your option) any later version.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "block/block.h"
+#include "qemu/rcu_queue.h"
+#include "qemu/sockets.h"
+#include "qemu/cutils.h"
+#include "trace.h"
+#ifdef CONFIG_EPOLL_CREATE1
+#include <sys/epoll.h>
+#endif
+
+struct AioHandler
+{
+ GPollFD pfd;
+ IOHandler *io_read;
+ IOHandler *io_write;
+ AioPollFn *io_poll;
+ IOHandler *io_poll_begin;
+ IOHandler *io_poll_end;
+ int deleted;
+ void *opaque;
+ bool is_external;
+ QLIST_ENTRY(AioHandler) node;
+};
+
+#ifdef CONFIG_EPOLL_CREATE1
+
+/* The fd number threashold to switch to epoll */
+#define EPOLL_ENABLE_THRESHOLD 64
+
+static void aio_epoll_disable(AioContext *ctx)
+{
+ ctx->epoll_available = false;
+ if (!ctx->epoll_enabled) {
+ return;
+ }
+ ctx->epoll_enabled = false;
+ close(ctx->epollfd);
+}
+
+static inline int epoll_events_from_pfd(int pfd_events)
+{
+ return (pfd_events & G_IO_IN ? EPOLLIN : 0) |
+ (pfd_events & G_IO_OUT ? EPOLLOUT : 0) |
+ (pfd_events & G_IO_HUP ? EPOLLHUP : 0) |
+ (pfd_events & G_IO_ERR ? EPOLLERR : 0);
+}
+
+static bool aio_epoll_try_enable(AioContext *ctx)
+{
+ AioHandler *node;
+ struct epoll_event event;
+
+ QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) {
+ int r;
+ if (node->deleted || !node->pfd.events) {
+ continue;
+ }
+ event.events = epoll_events_from_pfd(node->pfd.events);
+ event.data.ptr = node;
+ r = epoll_ctl(ctx->epollfd, EPOLL_CTL_ADD, node->pfd.fd, &event);
+ if (r) {
+ return false;
+ }
+ }
+ ctx->epoll_enabled = true;
+ return true;
+}
+
+static void aio_epoll_update(AioContext *ctx, AioHandler *node, bool is_new)
+{
+ struct epoll_event event;
+ int r;
+ int ctl;
+
+ if (!ctx->epoll_enabled) {
+ return;
+ }
+ if (!node->pfd.events) {
+ ctl = EPOLL_CTL_DEL;
+ } else {
+ event.data.ptr = node;
+ event.events = epoll_events_from_pfd(node->pfd.events);
+ ctl = is_new ? EPOLL_CTL_ADD : EPOLL_CTL_MOD;
+ }
+
+ r = epoll_ctl(ctx->epollfd, ctl, node->pfd.fd, &event);
+ if (r) {
+ aio_epoll_disable(ctx);
+ }
+}
+
+static int aio_epoll(AioContext *ctx, GPollFD *pfds,
+ unsigned npfd, int64_t timeout)
+{
+ AioHandler *node;
+ int i, ret = 0;
+ struct epoll_event events[128];
+
+ assert(npfd == 1);
+ assert(pfds[0].fd == ctx->epollfd);
+ if (timeout > 0) {
+ ret = qemu_poll_ns(pfds, npfd, timeout);
+ }
+ if (timeout <= 0 || ret > 0) {
+ ret = epoll_wait(ctx->epollfd, events,
+ sizeof(events) / sizeof(events[0]),
+ timeout);
+ if (ret <= 0) {
+ goto out;
+ }
+ for (i = 0; i < ret; i++) {
+ int ev = events[i].events;
+ node = events[i].data.ptr;
+ node->pfd.revents = (ev & EPOLLIN ? G_IO_IN : 0) |
+ (ev & EPOLLOUT ? G_IO_OUT : 0) |
+ (ev & EPOLLHUP ? G_IO_HUP : 0) |
+ (ev & EPOLLERR ? G_IO_ERR : 0);
+ }
+ }
+out:
+ return ret;
+}
+
+static bool aio_epoll_enabled(AioContext *ctx)
+{
+ /* Fall back to ppoll when external clients are disabled. */
+ return !aio_external_disabled(ctx) && ctx->epoll_enabled;
+}
+
+static bool aio_epoll_check_poll(AioContext *ctx, GPollFD *pfds,
+ unsigned npfd, int64_t timeout)
+{
+ if (!ctx->epoll_available) {
+ return false;
+ }
+ if (aio_epoll_enabled(ctx)) {
+ return true;
+ }
+ if (npfd >= EPOLL_ENABLE_THRESHOLD) {
+ if (aio_epoll_try_enable(ctx)) {
+ return true;
+ } else {
+ aio_epoll_disable(ctx);
+ }
+ }
+ return false;
+}
+
+#else
+
+static void aio_epoll_update(AioContext *ctx, AioHandler *node, bool is_new)
+{
+}
+
+static int aio_epoll(AioContext *ctx, GPollFD *pfds,
+ unsigned npfd, int64_t timeout)
+{
+ assert(false);
+}
+
+static bool aio_epoll_enabled(AioContext *ctx)
+{
+ return false;
+}
+
+static bool aio_epoll_check_poll(AioContext *ctx, GPollFD *pfds,
+ unsigned npfd, int64_t timeout)
+{
+ return false;
+}
+
+#endif
+
+static AioHandler *find_aio_handler(AioContext *ctx, int fd)
+{
+ AioHandler *node;
+
+ QLIST_FOREACH(node, &ctx->aio_handlers, node) {
+ if (node->pfd.fd == fd)
+ if (!node->deleted)
+ return node;
+ }
+
+ return NULL;
+}
+
+void aio_set_fd_handler(AioContext *ctx,
+ int fd,
+ bool is_external,
+ IOHandler *io_read,
+ IOHandler *io_write,
+ AioPollFn *io_poll,
+ void *opaque)
+{
+ AioHandler *node;
+ bool is_new = false;
+ bool deleted = false;
+
+ qemu_lockcnt_lock(&ctx->list_lock);
+
+ node = find_aio_handler(ctx, fd);
+
+ /* Are we deleting the fd handler? */
+ if (!io_read && !io_write && !io_poll) {
+ if (node == NULL) {
+ qemu_lockcnt_unlock(&ctx->list_lock);
+ return;
+ }
+
+ g_source_remove_poll(&ctx->source, &node->pfd);
+
+ /* If the lock is held, just mark the node as deleted */
+ if (qemu_lockcnt_count(&ctx->list_lock)) {
+ node->deleted = 1;
+ node->pfd.revents = 0;
+ } else {
+ /* Otherwise, delete it for real. We can't just mark it as
+ * deleted because deleted nodes are only cleaned up while
+ * no one is walking the handlers list.
+ */
+ QLIST_REMOVE(node, node);
+ deleted = true;
+ }
+
+ if (!node->io_poll) {
+ ctx->poll_disable_cnt--;
+ }
+ } else {
+ if (node == NULL) {
+ /* Alloc and insert if it's not already there */
+ node = g_new0(AioHandler, 1);
+ node->pfd.fd = fd;
+ QLIST_INSERT_HEAD_RCU(&ctx->aio_handlers, node, node);
+
+ g_source_add_poll(&ctx->source, &node->pfd);
+ is_new = true;
+
+ ctx->poll_disable_cnt += !io_poll;
+ } else {
+ ctx->poll_disable_cnt += !io_poll - !node->io_poll;
+ }
+
+ /* Update handler with latest information */
+ node->io_read = io_read;
+ node->io_write = io_write;
+ node->io_poll = io_poll;
+ node->opaque = opaque;
+ node->is_external = is_external;
+
+ node->pfd.events = (io_read ? G_IO_IN | G_IO_HUP | G_IO_ERR : 0);
+ node->pfd.events |= (io_write ? G_IO_OUT | G_IO_ERR : 0);
+ }
+
+ aio_epoll_update(ctx, node, is_new);
+ qemu_lockcnt_unlock(&ctx->list_lock);
+ aio_notify(ctx);
+
+ if (deleted) {
+ g_free(node);
+ }
+}
+
+void aio_set_fd_poll(AioContext *ctx, int fd,
+ IOHandler *io_poll_begin,
+ IOHandler *io_poll_end)
+{
+ AioHandler *node = find_aio_handler(ctx, fd);
+
+ if (!node) {
+ return;
+ }
+
+ node->io_poll_begin = io_poll_begin;
+ node->io_poll_end = io_poll_end;
+}
+
+void aio_set_event_notifier(AioContext *ctx,
+ EventNotifier *notifier,
+ bool is_external,
+ EventNotifierHandler *io_read,
+ AioPollFn *io_poll)
+{
+ aio_set_fd_handler(ctx, event_notifier_get_fd(notifier), is_external,
+ (IOHandler *)io_read, NULL, io_poll, notifier);
+}
+
+void aio_set_event_notifier_poll(AioContext *ctx,
+ EventNotifier *notifier,
+ EventNotifierHandler *io_poll_begin,
+ EventNotifierHandler *io_poll_end)
+{
+ aio_set_fd_poll(ctx, event_notifier_get_fd(notifier),
+ (IOHandler *)io_poll_begin,
+ (IOHandler *)io_poll_end);
+}
+
+static void poll_set_started(AioContext *ctx, bool started)
+{
+ AioHandler *node;
+
+ if (started == ctx->poll_started) {
+ return;
+ }
+
+ ctx->poll_started = started;
+
+ qemu_lockcnt_inc(&ctx->list_lock);
+ QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) {
+ IOHandler *fn;
+
+ if (node->deleted) {
+ continue;
+ }
+
+ if (started) {
+ fn = node->io_poll_begin;
+ } else {
+ fn = node->io_poll_end;
+ }
+
+ if (fn) {
+ fn(node->opaque);
+ }
+ }
+ qemu_lockcnt_dec(&ctx->list_lock);
+}
+
+
+bool aio_prepare(AioContext *ctx)
+{
+ /* Poll mode cannot be used with glib's event loop, disable it. */
+ poll_set_started(ctx, false);
+
+ return false;
+}
+
+bool aio_pending(AioContext *ctx)
+{
+ AioHandler *node;
+ bool result = false;
+
+ /*
+ * We have to walk very carefully in case aio_set_fd_handler is
+ * called while we're walking.
+ */
+ qemu_lockcnt_inc(&ctx->list_lock);
+
+ QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) {
+ int revents;
+
+ revents = node->pfd.revents & node->pfd.events;
+ if (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR) && node->io_read &&
+ aio_node_check(ctx, node->is_external)) {
+ result = true;
+ break;
+ }
+ if (revents & (G_IO_OUT | G_IO_ERR) && node->io_write &&
+ aio_node_check(ctx, node->is_external)) {
+ result = true;
+ break;
+ }
+ }
+ qemu_lockcnt_dec(&ctx->list_lock);
+
+ return result;
+}
+
+static bool aio_dispatch_handlers(AioContext *ctx)
+{
+ AioHandler *node, *tmp;
+ bool progress = false;
+
+ /*
+ * We have to walk very carefully in case aio_set_fd_handler is
+ * called while we're walking.
+ */
+ qemu_lockcnt_inc(&ctx->list_lock);
+
+ QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) {
+ int revents;
+
+ revents = node->pfd.revents & node->pfd.events;
+ node->pfd.revents = 0;
+
+ if (!node->deleted &&
+ (revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) &&
+ aio_node_check(ctx, node->is_external) &&
+ node->io_read) {
+ node->io_read(node->opaque);
+
+ /* aio_notify() does not count as progress */
+ if (node->opaque != &ctx->notifier) {
+ progress = true;
+ }
+ }
+ if (!node->deleted &&
+ (revents & (G_IO_OUT | G_IO_ERR)) &&
+ aio_node_check(ctx, node->is_external) &&
+ node->io_write) {
+ node->io_write(node->opaque);
+ progress = true;
+ }
+
+ if (node->deleted) {
+ if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {
+ QLIST_REMOVE(node, node);
+ g_free(node);
+ qemu_lockcnt_inc_and_unlock(&ctx->list_lock);
+ }
+ }
+ }
+
+ qemu_lockcnt_dec(&ctx->list_lock);
+ return progress;
+}
+
+/*
+ * Note that dispatch_fds == false has the side-effect of post-poning the
+ * freeing of deleted handlers.
+ */
+bool aio_dispatch(AioContext *ctx, bool dispatch_fds)
+{
+ bool progress;
+
+ /*
+ * If there are callbacks left that have been queued, we need to call them.
+ * Do not call select in this case, because it is possible that the caller
+ * does not need a complete flush (as is the case for aio_poll loops).
+ */
+ progress = aio_bh_poll(ctx);
+
+ if (dispatch_fds) {
+ progress |= aio_dispatch_handlers(ctx);
+ }
+
+ /* Run our timers */
+ progress |= timerlistgroup_run_timers(&ctx->tlg);
+
+ return progress;
+}
+
+/* These thread-local variables are used only in a small part of aio_poll
+ * around the call to the poll() system call. In particular they are not
+ * used while aio_poll is performing callbacks, which makes it much easier
+ * to think about reentrancy!
+ *
+ * Stack-allocated arrays would be perfect but they have size limitations;
+ * heap allocation is expensive enough that we want to reuse arrays across
+ * calls to aio_poll(). And because poll() has to be called without holding
+ * any lock, the arrays cannot be stored in AioContext. Thread-local data
+ * has none of the disadvantages of these three options.
+ */
+static __thread GPollFD *pollfds;
+static __thread AioHandler **nodes;
+static __thread unsigned npfd, nalloc;
+static __thread Notifier pollfds_cleanup_notifier;
+
+static void pollfds_cleanup(Notifier *n, void *unused)
+{
+ g_assert(npfd == 0);
+ g_free(pollfds);
+ g_free(nodes);
+ nalloc = 0;
+}
+
+static void add_pollfd(AioHandler *node)
+{
+ if (npfd == nalloc) {
+ if (nalloc == 0) {
+ pollfds_cleanup_notifier.notify = pollfds_cleanup;
+ qemu_thread_atexit_add(&pollfds_cleanup_notifier);
+ nalloc = 8;
+ } else {
+ g_assert(nalloc <= INT_MAX);
+ nalloc *= 2;
+ }
+ pollfds = g_renew(GPollFD, pollfds, nalloc);
+ nodes = g_renew(AioHandler *, nodes, nalloc);
+ }
+ nodes[npfd] = node;
+ pollfds[npfd] = (GPollFD) {
+ .fd = node->pfd.fd,
+ .events = node->pfd.events,
+ };
+ npfd++;
+}
+
+static bool run_poll_handlers_once(AioContext *ctx)
+{
+ bool progress = false;
+ AioHandler *node;
+
+ QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) {
+ if (!node->deleted && node->io_poll &&
+ aio_node_check(ctx, node->is_external) &&
+ node->io_poll(node->opaque)) {
+ progress = true;
+ }
+
+ /* Caller handles freeing deleted nodes. Don't do it here. */
+ }
+
+ return progress;
+}
+
+/* run_poll_handlers:
+ * @ctx: the AioContext
+ * @max_ns: maximum time to poll for, in nanoseconds
+ *
+ * Polls for a given time.
+ *
+ * Note that ctx->notify_me must be non-zero so this function can detect
+ * aio_notify().
+ *
+ * Note that the caller must have incremented ctx->list_lock.
+ *
+ * Returns: true if progress was made, false otherwise
+ */
+static bool run_poll_handlers(AioContext *ctx, int64_t max_ns)
+{
+ bool progress;
+ int64_t end_time;
+
+ assert(ctx->notify_me);
+ assert(qemu_lockcnt_count(&ctx->list_lock) > 0);
+ assert(ctx->poll_disable_cnt == 0);
+
+ trace_run_poll_handlers_begin(ctx, max_ns);
+
+ end_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + max_ns;
+
+ do {
+ progress = run_poll_handlers_once(ctx);
+ } while (!progress && qemu_clock_get_ns(QEMU_CLOCK_REALTIME) < end_time);
+
+ trace_run_poll_handlers_end(ctx, progress);
+
+ return progress;
+}
+
+/* try_poll_mode:
+ * @ctx: the AioContext
+ * @blocking: busy polling is only attempted when blocking is true
+ *
+ * ctx->notify_me must be non-zero so this function can detect aio_notify().
+ *
+ * Note that the caller must have incremented ctx->list_lock.
+ *
+ * Returns: true if progress was made, false otherwise
+ */
+static bool try_poll_mode(AioContext *ctx, bool blocking)
+{
+ if (blocking && ctx->poll_max_ns && ctx->poll_disable_cnt == 0) {
+ /* See qemu_soonest_timeout() uint64_t hack */
+ int64_t max_ns = MIN((uint64_t)aio_compute_timeout(ctx),
+ (uint64_t)ctx->poll_ns);
+
+ if (max_ns) {
+ poll_set_started(ctx, true);
+
+ if (run_poll_handlers(ctx, max_ns)) {
+ return true;
+ }
+ }
+ }
+
+ poll_set_started(ctx, false);
+
+ /* Even if we don't run busy polling, try polling once in case it can make
+ * progress and the caller will be able to avoid ppoll(2)/epoll_wait(2).
+ */
+ return run_poll_handlers_once(ctx);
+}
+
+bool aio_poll(AioContext *ctx, bool blocking)
+{
+ AioHandler *node;
+ int i;
+ int ret = 0;
+ bool progress;
+ int64_t timeout;
+ int64_t start = 0;
+
+ aio_context_acquire(ctx);
+ progress = false;
+
+ /* aio_notify can avoid the expensive event_notifier_set if
+ * everything (file descriptors, bottom halves, timers) will
+ * be re-evaluated before the next blocking poll(). This is
+ * already true when aio_poll is called with blocking == false;
+ * if blocking == true, it is only true after poll() returns,
+ * so disable the optimization now.
+ */
+ if (blocking) {
+ atomic_add(&ctx->notify_me, 2);
+ }
+
+ qemu_lockcnt_inc(&ctx->list_lock);
+
+ if (ctx->poll_max_ns) {
+ start = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
+ }
+
+ if (try_poll_mode(ctx, blocking)) {
+ progress = true;
+ } else {
+ assert(npfd == 0);
+
+ /* fill pollfds */
+
+ if (!aio_epoll_enabled(ctx)) {
+ QLIST_FOREACH_RCU(node, &ctx->aio_handlers, node) {
+ if (!node->deleted && node->pfd.events
+ && aio_node_check(ctx, node->is_external)) {
+ add_pollfd(node);
+ }
+ }
+ }
+
+ timeout = blocking ? aio_compute_timeout(ctx) : 0;
+
+ /* wait until next event */
+ if (timeout) {
+ aio_context_release(ctx);
+ }
+ if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) {
+ AioHandler epoll_handler;
+
+ epoll_handler.pfd.fd = ctx->epollfd;
+ epoll_handler.pfd.events = G_IO_IN | G_IO_OUT | G_IO_HUP | G_IO_ERR;
+ npfd = 0;
+ add_pollfd(&epoll_handler);
+ ret = aio_epoll(ctx, pollfds, npfd, timeout);
+ } else {
+ ret = qemu_poll_ns(pollfds, npfd, timeout);
+ }
+ if (timeout) {
+ aio_context_acquire(ctx);
+ }
+ }
+
+ if (blocking) {
+ atomic_sub(&ctx->notify_me, 2);
+ }
+
+ /* Adjust polling time */
+ if (ctx->poll_max_ns) {
+ int64_t block_ns = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - start;
+
+ if (block_ns <= ctx->poll_ns) {
+ /* This is the sweet spot, no adjustment needed */
+ } else if (block_ns > ctx->poll_max_ns) {
+ /* We'd have to poll for too long, poll less */
+ int64_t old = ctx->poll_ns;
+
+ if (ctx->poll_shrink) {
+ ctx->poll_ns /= ctx->poll_shrink;
+ } else {
+ ctx->poll_ns = 0;
+ }
+
+ trace_poll_shrink(ctx, old, ctx->poll_ns);
+ } else if (ctx->poll_ns < ctx->poll_max_ns &&
+ block_ns < ctx->poll_max_ns) {
+ /* There is room to grow, poll longer */
+ int64_t old = ctx->poll_ns;
+ int64_t grow = ctx->poll_grow;
+
+ if (grow == 0) {
+ grow = 2;
+ }
+
+ if (ctx->poll_ns) {
+ ctx->poll_ns *= grow;
+ } else {
+ ctx->poll_ns = 4000; /* start polling at 4 microseconds */
+ }
+
+ if (ctx->poll_ns > ctx->poll_max_ns) {
+ ctx->poll_ns = ctx->poll_max_ns;
+ }
+
+ trace_poll_grow(ctx, old, ctx->poll_ns);
+ }
+ }
+
+ aio_notify_accept(ctx);
+
+ /* if we have any readable fds, dispatch event */
+ if (ret > 0) {
+ for (i = 0; i < npfd; i++) {
+ nodes[i]->pfd.revents = pollfds[i].revents;
+ }
+ }
+
+ npfd = 0;
+ qemu_lockcnt_dec(&ctx->list_lock);
+
+ /* Run dispatch even if there were no readable fds to run timers */
+ if (aio_dispatch(ctx, ret > 0)) {
+ progress = true;
+ }
+
+ aio_context_release(ctx);
+
+ return progress;
+}
+
+void aio_context_setup(AioContext *ctx)
+{
+ /* TODO remove this in final patch submission */
+ if (getenv("QEMU_AIO_POLL_MAX_NS")) {
+ fprintf(stderr, "The QEMU_AIO_POLL_MAX_NS environment variable has "
+ "been replaced with -object iothread,poll-max-ns=NUM\n");
+ exit(1);
+ }
+
+#ifdef CONFIG_EPOLL_CREATE1
+ assert(!ctx->epollfd);
+ ctx->epollfd = epoll_create1(EPOLL_CLOEXEC);
+ if (ctx->epollfd == -1) {
+ fprintf(stderr, "Failed to create epoll instance: %s", strerror(errno));
+ ctx->epoll_available = false;
+ } else {
+ ctx->epoll_available = true;
+ }
+#endif
+}
+
+void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns,
+ int64_t grow, int64_t shrink, Error **errp)
+{
+ /* No thread synchronization here, it doesn't matter if an incorrect value
+ * is used once.
+ */
+ ctx->poll_max_ns = max_ns;
+ ctx->poll_ns = 0;
+ ctx->poll_grow = grow;
+ ctx->poll_shrink = shrink;
+
+ aio_notify(ctx);
+}