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iohandler: Use aio API

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iohandler.c shares the same interface with aio, but with duplicated
code. It's better to rebase iohandler, also because that aio is a
more friendly interface to multi-threads.

Create a global AioContext instance and let its GSource handle the
iohandler events.

Signed-off-by: Fam Zheng <famz@redhat.com>
Message-Id: <1441596538-4412-1-git-send-email-famz@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Fam Zheng
2015-09-07 11:28:58 +08:00
committed by Paolo Bonzini
parent 46036b2462
commit f3926945c8
3 changed files with 21 additions and 102 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
include/qemu/main-loop.h
View File

@@ -203,6 +203,7 @@ void qemu_set_fd_handler(int fd,
IOHandler *fd_write,
void *opaque);
GSource *iohandler_get_g_source(void);
#ifdef CONFIG_POSIX
/**
* qemu_add_child_watch: Register a child process for reaping.
@@ -265,8 +266,6 @@ void qemu_mutex_unlock_iothread(void);
/* internal interfaces */
void qemu_fd_register(int fd);
void qemu_iohandler_fill(GArray *pollfds);
void qemu_iohandler_poll(GArray *pollfds, int rc);
QEMUBH *qemu_bh_new(QEMUBHFunc *cb, void *opaque);
void qemu_bh_schedule_idle(QEMUBH *bh);

115
iohandler.c
View File

@@ -32,111 +32,30 @@
#include <sys/wait.h>
#endif
typedef struct IOHandlerRecord {
IOHandler *fd_read;
IOHandler *fd_write;
void *opaque;
QLIST_ENTRY(IOHandlerRecord) next;
int fd;
int pollfds_idx;
bool deleted;
} IOHandlerRecord;
/* This context runs on top of main loop. We can't reuse qemu_aio_context
* because iohandlers mustn't be polled by aio_poll(qemu_aio_context). */
static AioContext *iohandler_ctx;
static QLIST_HEAD(, IOHandlerRecord) io_handlers =
QLIST_HEAD_INITIALIZER(io_handlers);
static void iohandler_init(void)
{
if (!iohandler_ctx) {
iohandler_ctx = aio_context_new(&error_abort);
}
}
GSource *iohandler_get_g_source(void)
{
iohandler_init();
return aio_get_g_source(iohandler_ctx);
}
void qemu_set_fd_handler(int fd,
IOHandler *fd_read,
IOHandler *fd_write,
void *opaque)
{
IOHandlerRecord *ioh;
assert(fd >= 0);
if (!fd_read && !fd_write) {
QLIST_FOREACH(ioh, &io_handlers, next) {
if (ioh->fd == fd) {
ioh->deleted = 1;
break;
}
}
} else {
QLIST_FOREACH(ioh, &io_handlers, next) {
if (ioh->fd == fd)
goto found;
}
ioh = g_malloc0(sizeof(IOHandlerRecord));
QLIST_INSERT_HEAD(&io_handlers, ioh, next);
found:
ioh->fd = fd;
ioh->fd_read = fd_read;
ioh->fd_write = fd_write;
ioh->opaque = opaque;
ioh->pollfds_idx = -1;
ioh->deleted = 0;
qemu_notify_event();
}
}
void qemu_iohandler_fill(GArray *pollfds)
{
IOHandlerRecord *ioh;
QLIST_FOREACH(ioh, &io_handlers, next) {
int events = 0;
if (ioh->deleted)
continue;
if (ioh->fd_read) {
events |= G_IO_IN | G_IO_HUP | G_IO_ERR;
}
if (ioh->fd_write) {
events |= G_IO_OUT | G_IO_ERR;
}
if (events) {
GPollFD pfd = {
.fd = ioh->fd,
.events = events,
};
ioh->pollfds_idx = pollfds->len;
g_array_append_val(pollfds, pfd);
} else {
ioh->pollfds_idx = -1;
}
}
}
void qemu_iohandler_poll(GArray *pollfds, int ret)
{
if (ret > 0) {
IOHandlerRecord *pioh, *ioh;
QLIST_FOREACH_SAFE(ioh, &io_handlers, next, pioh) {
int revents = 0;
if (!ioh->deleted && ioh->pollfds_idx != -1) {
GPollFD *pfd = &g_array_index(pollfds, GPollFD,
ioh->pollfds_idx);
revents = pfd->revents;
}
if (!ioh->deleted && ioh->fd_read &&
(revents & (G_IO_IN | G_IO_HUP | G_IO_ERR))) {
ioh->fd_read(ioh->opaque);
}
if (!ioh->deleted && ioh->fd_write &&
(revents & (G_IO_OUT | G_IO_ERR))) {
ioh->fd_write(ioh->opaque);
}
/* Do this last in case read/write handlers marked it for deletion */
if (ioh->deleted) {
QLIST_REMOVE(ioh, next);
g_free(ioh);
}
}
}
iohandler_init();
aio_set_fd_handler(iohandler_ctx, fd, fd_read, fd_write, opaque);
}
/* reaping of zombies. right now we're not passing the status to

5
main-loop.c
View File

@@ -161,6 +161,9 @@ int qemu_init_main_loop(Error **errp)
src = aio_get_g_source(qemu_aio_context);
g_source_attach(src, NULL);
g_source_unref(src);
src = iohandler_get_g_source();
g_source_attach(src, NULL);
g_source_unref(src);
return 0;
}
@@ -487,7 +490,6 @@ int main_loop_wait(int nonblocking)
#ifdef CONFIG_SLIRP
slirp_pollfds_fill(gpollfds, &timeout);
#endif
qemu_iohandler_fill(gpollfds);
if (timeout == UINT32_MAX) {
timeout_ns = -1;
@@ -500,7 +502,6 @@ int main_loop_wait(int nonblocking)
&main_loop_tlg));
ret = os_host_main_loop_wait(timeout_ns);
qemu_iohandler_poll(gpollfds, ret);
#ifdef CONFIG_SLIRP
slirp_pollfds_poll(gpollfds, (ret < 0));
#endif