No header includes qemu-common.h after this commit, as prescribed by qemu-common.h's file comment. Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190523143508.25387-5-armbru@redhat.com> [Rebased with conflicts resolved automatically, except for include/hw/arm/xlnx-zynqmp.h hw/arm/nrf51_soc.c hw/arm/msf2-soc.c block/qcow2-refcount.c block/qcow2-cluster.c block/qcow2-cache.c target/arm/cpu.h target/lm32/cpu.h target/m68k/cpu.h target/mips/cpu.h target/moxie/cpu.h target/nios2/cpu.h target/openrisc/cpu.h target/riscv/cpu.h target/tilegx/cpu.h target/tricore/cpu.h target/unicore32/cpu.h target/xtensa/cpu.h; bsd-user/main.c and net/tap-bsd.c fixed up]
775 lines
21 KiB
C
775 lines
21 KiB
C
/*
|
|
* 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 "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 threshold to switch to epoll */
|
|
#define EPOLL_ENABLE_THRESHOLD 64
|
|
|
|
static void aio_epoll_disable(AioContext *ctx)
|
|
{
|
|
ctx->epoll_enabled = false;
|
|
if (!ctx->epoll_available) {
|
|
return;
|
|
}
|
|
ctx->epoll_available = 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,
|
|
ARRAY_SIZE(events),
|
|
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;
|
|
}
|
|
|
|
static bool aio_remove_fd_handler(AioContext *ctx, AioHandler *node)
|
|
{
|
|
/* If the GSource is in the process of being destroyed then
|
|
* g_source_remove_poll() causes an assertion failure. Skip
|
|
* removal in that case, because glib cleans up its state during
|
|
* destruction anyway.
|
|
*/
|
|
if (!g_source_is_destroyed(&ctx->source)) {
|
|
g_source_remove_poll(&ctx->source, &node->pfd);
|
|
}
|
|
|
|
/* If a read is in progress, just mark the node as deleted */
|
|
if (qemu_lockcnt_count(&ctx->list_lock)) {
|
|
node->deleted = 1;
|
|
node->pfd.revents = 0;
|
|
return false;
|
|
}
|
|
/* 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);
|
|
return true;
|
|
}
|
|
|
|
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;
|
|
AioHandler *new_node = NULL;
|
|
bool is_new = false;
|
|
bool deleted = false;
|
|
int poll_disable_change;
|
|
|
|
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;
|
|
}
|
|
/* Clean events in order to unregister fd from the ctx epoll. */
|
|
node->pfd.events = 0;
|
|
|
|
poll_disable_change = -!node->io_poll;
|
|
} else {
|
|
poll_disable_change = !io_poll - (node && !node->io_poll);
|
|
if (node == NULL) {
|
|
is_new = true;
|
|
}
|
|
/* Alloc and insert if it's not already there */
|
|
new_node = g_new0(AioHandler, 1);
|
|
|
|
/* Update handler with latest information */
|
|
new_node->io_read = io_read;
|
|
new_node->io_write = io_write;
|
|
new_node->io_poll = io_poll;
|
|
new_node->opaque = opaque;
|
|
new_node->is_external = is_external;
|
|
|
|
if (is_new) {
|
|
new_node->pfd.fd = fd;
|
|
} else {
|
|
new_node->pfd = node->pfd;
|
|
}
|
|
g_source_add_poll(&ctx->source, &new_node->pfd);
|
|
|
|
new_node->pfd.events = (io_read ? G_IO_IN | G_IO_HUP | G_IO_ERR : 0);
|
|
new_node->pfd.events |= (io_write ? G_IO_OUT | G_IO_ERR : 0);
|
|
|
|
QLIST_INSERT_HEAD_RCU(&ctx->aio_handlers, new_node, node);
|
|
}
|
|
if (node) {
|
|
deleted = aio_remove_fd_handler(ctx, node);
|
|
}
|
|
|
|
/* No need to order poll_disable_cnt writes against other updates;
|
|
* the counter is only used to avoid wasting time and latency on
|
|
* iterated polling when the system call will be ultimately necessary.
|
|
* Changing handlers is a rare event, and a little wasted polling until
|
|
* the aio_notify below is not an issue.
|
|
*/
|
|
atomic_set(&ctx->poll_disable_cnt,
|
|
atomic_read(&ctx->poll_disable_cnt) + poll_disable_change);
|
|
|
|
if (new_node) {
|
|
aio_epoll_update(ctx, new_node, is_new);
|
|
} else if (node) {
|
|
/* Unregister deleted fd_handler */
|
|
aio_epoll_update(ctx, node, false);
|
|
}
|
|
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;
|
|
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
|
|
return progress;
|
|
}
|
|
|
|
void aio_dispatch(AioContext *ctx)
|
|
{
|
|
qemu_lockcnt_inc(&ctx->list_lock);
|
|
aio_bh_poll(ctx);
|
|
aio_dispatch_handlers(ctx);
|
|
qemu_lockcnt_dec(&ctx->list_lock);
|
|
|
|
timerlistgroup_run_timers(&ctx->tlg);
|
|
}
|
|
|
|
/* 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, int64_t *timeout)
|
|
{
|
|
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)) {
|
|
/*
|
|
* Polling was successful, exit try_poll_mode immediately
|
|
* to adjust the next polling time.
|
|
*/
|
|
*timeout = 0;
|
|
if (node->opaque != &ctx->notifier) {
|
|
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, int64_t *timeout)
|
|
{
|
|
bool progress;
|
|
int64_t start_time, elapsed_time;
|
|
|
|
assert(ctx->notify_me);
|
|
assert(qemu_lockcnt_count(&ctx->list_lock) > 0);
|
|
|
|
trace_run_poll_handlers_begin(ctx, max_ns, *timeout);
|
|
|
|
start_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
|
|
do {
|
|
progress = run_poll_handlers_once(ctx, timeout);
|
|
elapsed_time = qemu_clock_get_ns(QEMU_CLOCK_REALTIME) - start_time;
|
|
max_ns = qemu_soonest_timeout(*timeout, max_ns);
|
|
assert(!(max_ns && progress));
|
|
} while (elapsed_time < max_ns && !atomic_read(&ctx->poll_disable_cnt));
|
|
|
|
/* If time has passed with no successful polling, adjust *timeout to
|
|
* keep the same ending time.
|
|
*/
|
|
if (*timeout != -1) {
|
|
*timeout -= MIN(*timeout, elapsed_time);
|
|
}
|
|
|
|
trace_run_poll_handlers_end(ctx, progress, *timeout);
|
|
return progress;
|
|
}
|
|
|
|
/* try_poll_mode:
|
|
* @ctx: the AioContext
|
|
* @timeout: timeout for blocking wait, computed by the caller and updated if
|
|
* polling succeeds.
|
|
*
|
|
* 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, int64_t *timeout)
|
|
{
|
|
int64_t max_ns = qemu_soonest_timeout(*timeout, ctx->poll_ns);
|
|
|
|
if (max_ns && !atomic_read(&ctx->poll_disable_cnt)) {
|
|
poll_set_started(ctx, true);
|
|
|
|
if (run_poll_handlers(ctx, max_ns, timeout)) {
|
|
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, timeout);
|
|
}
|
|
|
|
bool aio_poll(AioContext *ctx, bool blocking)
|
|
{
|
|
AioHandler *node;
|
|
int i;
|
|
int ret = 0;
|
|
bool progress;
|
|
int64_t timeout;
|
|
int64_t start = 0;
|
|
|
|
assert(in_aio_context_home_thread(ctx));
|
|
|
|
/* 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);
|
|
}
|
|
|
|
timeout = blocking ? aio_compute_timeout(ctx) : 0;
|
|
progress = try_poll_mode(ctx, &timeout);
|
|
assert(!(timeout && progress));
|
|
|
|
/* If polling is allowed, non-blocking aio_poll does not need the
|
|
* system call---a single round of run_poll_handlers_once suffices.
|
|
*/
|
|
if (timeout || atomic_read(&ctx->poll_disable_cnt)) {
|
|
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);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* wait until next event */
|
|
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 (blocking) {
|
|
atomic_sub(&ctx->notify_me, 2);
|
|
aio_notify_accept(ctx);
|
|
}
|
|
|
|
/* 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);
|
|
}
|
|
}
|
|
|
|
/* 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;
|
|
|
|
progress |= aio_bh_poll(ctx);
|
|
|
|
if (ret > 0) {
|
|
progress |= aio_dispatch_handlers(ctx);
|
|
}
|
|
|
|
qemu_lockcnt_dec(&ctx->list_lock);
|
|
|
|
progress |= timerlistgroup_run_timers(&ctx->tlg);
|
|
|
|
return progress;
|
|
}
|
|
|
|
void aio_context_setup(AioContext *ctx)
|
|
{
|
|
#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_destroy(AioContext *ctx)
|
|
{
|
|
#ifdef CONFIG_EPOLL_CREATE1
|
|
aio_epoll_disable(ctx);
|
|
#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);
|
|
}
|