diff options
| -rw-r--r-- | util/aio-posix.c | 110 |
1 files changed, 78 insertions, 32 deletions
diff --git a/util/aio-posix.c b/util/aio-posix.c index b5cfdbd2f6..9e1befc0c0 100644 --- a/util/aio-posix.c +++ b/util/aio-posix.c @@ -35,9 +35,20 @@ struct AioHandler void *opaque; bool is_external; QLIST_ENTRY(AioHandler) node; + QLIST_ENTRY(AioHandler) node_ready; /* only used during aio_poll() */ QLIST_ENTRY(AioHandler) node_deleted; }; +/* Add a handler to a ready list */ +static void add_ready_handler(AioHandlerList *ready_list, + AioHandler *node, + int revents) +{ + QLIST_SAFE_REMOVE(node, node_ready); /* remove from nested parent's list */ + node->pfd.revents = revents; + QLIST_INSERT_HEAD(ready_list, node, node_ready); +} + #ifdef CONFIG_EPOLL_CREATE1 /* The fd number threshold to switch to epoll */ @@ -105,7 +116,8 @@ static void aio_epoll_update(AioContext *ctx, AioHandler *node, bool is_new) } } -static int aio_epoll(AioContext *ctx, int64_t timeout) +static int aio_epoll(AioContext *ctx, AioHandlerList *ready_list, + int64_t timeout) { GPollFD pfd = { .fd = ctx->epollfd, @@ -130,11 +142,13 @@ static int aio_epoll(AioContext *ctx, int64_t timeout) } for (i = 0; i < ret; i++) { int ev = events[i].events; + int 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); + 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); + add_ready_handler(ready_list, node, revents); } } out: @@ -172,8 +186,8 @@ 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) +static int aio_epoll(AioContext *ctx, AioHandlerList *ready_list, + int64_t timeout) { assert(false); } @@ -438,36 +452,63 @@ static void aio_free_deleted_handlers(AioContext *ctx) qemu_lockcnt_inc_and_unlock(&ctx->list_lock); } -static bool aio_dispatch_handlers(AioContext *ctx) +static bool aio_dispatch_handler(AioContext *ctx, AioHandler *node) { - AioHandler *node, *tmp; bool progress = false; + int revents; - QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) { - int revents; + revents = node->pfd.revents & node->pfd.events; + node->pfd.revents = 0; - revents = node->pfd.revents & node->pfd.events; - node->pfd.revents = 0; + if (!QLIST_IS_INSERTED(node, 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); - if (!QLIST_IS_INSERTED(node, 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 (!QLIST_IS_INSERTED(node, node_deleted) && - (revents & (G_IO_OUT | G_IO_ERR)) && - aio_node_check(ctx, node->is_external) && - node->io_write) { - node->io_write(node->opaque); + /* aio_notify() does not count as progress */ + if (node->opaque != &ctx->notifier) { progress = true; } } + if (!QLIST_IS_INSERTED(node, 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; + } + + return progress; +} + +/* + * If we have a list of ready handlers then this is more efficient than + * scanning all handlers with aio_dispatch_handlers(). + */ +static bool aio_dispatch_ready_handlers(AioContext *ctx, + AioHandlerList *ready_list) +{ + bool progress = false; + AioHandler *node; + + while ((node = QLIST_FIRST(ready_list))) { + QLIST_SAFE_REMOVE(node, node_ready); + progress = aio_dispatch_handler(ctx, node) || progress; + } + + return progress; +} + +/* Slower than aio_dispatch_ready_handlers() but only used via glib */ +static bool aio_dispatch_handlers(AioContext *ctx) +{ + AioHandler *node, *tmp; + bool progress = false; + + QLIST_FOREACH_SAFE_RCU(node, &ctx->aio_handlers, node, tmp) { + progress = aio_dispatch_handler(ctx, node) || progress; + } return progress; } @@ -639,6 +680,7 @@ static bool try_poll_mode(AioContext *ctx, int64_t *timeout) bool aio_poll(AioContext *ctx, bool blocking) { + AioHandlerList ready_list = QLIST_HEAD_INITIALIZER(ready_list); AioHandler *node; int i; int ret = 0; @@ -689,7 +731,7 @@ bool aio_poll(AioContext *ctx, bool blocking) /* wait until next event */ if (aio_epoll_check_poll(ctx, pollfds, npfd, timeout)) { npfd = 0; /* pollfds[] is not being used */ - ret = aio_epoll(ctx, timeout); + ret = aio_epoll(ctx, &ready_list, timeout); } else { ret = qemu_poll_ns(pollfds, npfd, timeout); } @@ -744,7 +786,11 @@ bool aio_poll(AioContext *ctx, bool blocking) /* if we have any readable fds, dispatch event */ if (ret > 0) { for (i = 0; i < npfd; i++) { - nodes[i]->pfd.revents = pollfds[i].revents; + int revents = pollfds[i].revents; + + if (revents) { + add_ready_handler(&ready_list, nodes[i], revents); + } } } @@ -753,7 +799,7 @@ bool aio_poll(AioContext *ctx, bool blocking) progress |= aio_bh_poll(ctx); if (ret > 0) { - progress |= aio_dispatch_handlers(ctx); + progress |= aio_dispatch_ready_handlers(ctx, &ready_list); } aio_free_deleted_handlers(ctx); |