diff options
Diffstat (limited to 'util/aio-posix.c')
| -rw-r--r-- | util/aio-posix.c | 286 |
1 files changed, 12 insertions, 274 deletions
diff --git a/util/aio-posix.c b/util/aio-posix.c index 11a4971955..bc0b86547c 100644 --- a/util/aio-posix.c +++ b/util/aio-posix.c @@ -20,191 +20,17 @@ #include "qemu/sockets.h" #include "qemu/cutils.h" #include "trace.h" -#ifdef CONFIG_EPOLL_CREATE1 -#include <sys/epoll.h> -#endif +#include "aio-posix.h" -struct AioHandler -{ - GPollFD pfd; - IOHandler *io_read; - IOHandler *io_write; - AioPollFn *io_poll; - IOHandler *io_poll_begin; - IOHandler *io_poll_end; - 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) +void aio_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 */ -#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 (QLIST_IS_INSERTED(node, 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, AioHandlerList *ready_list, - int64_t timeout) -{ - GPollFD pfd = { - .fd = ctx->epollfd, - .events = G_IO_IN | G_IO_OUT | G_IO_HUP | G_IO_ERR, - }; - AioHandler *node; - int i, ret = 0; - struct epoll_event events[128]; - - if (timeout > 0) { - ret = qemu_poll_ns(&pfd, 1, timeout); - if (ret > 0) { - timeout = 0; - } - } - 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; - 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; - add_ready_handler(ready_list, node, revents); - } - } -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, AioHandlerList *ready_list, - 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; @@ -314,10 +140,10 @@ void aio_set_fd_handler(AioContext *ctx, atomic_read(&ctx->poll_disable_cnt) + poll_disable_change); if (new_node) { - aio_epoll_update(ctx, new_node, is_new); + ctx->fdmon_ops->update(ctx, new_node, is_new); } else if (node) { /* Unregister deleted fd_handler */ - aio_epoll_update(ctx, node, false); + ctx->fdmon_ops->update(ctx, node, false); } qemu_lockcnt_unlock(&ctx->list_lock); aio_notify(ctx); @@ -532,52 +358,6 @@ void aio_dispatch(AioContext *ctx) 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; @@ -689,8 +469,6 @@ 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; bool progress; int64_t timeout; @@ -723,26 +501,7 @@ bool aio_poll(AioContext *ctx, bool blocking) * 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 (!QLIST_IS_INSERTED(node, 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)) { - npfd = 0; /* pollfds[] is not being used */ - ret = aio_epoll(ctx, &ready_list, timeout); - } else { - ret = qemu_poll_ns(pollfds, npfd, timeout); - } + ret = ctx->fdmon_ops->wait(ctx, &ready_list, timeout); } if (blocking) { @@ -791,19 +550,6 @@ bool aio_poll(AioContext *ctx, bool blocking) } } - /* if we have any readable fds, dispatch event */ - if (ret > 0) { - for (i = 0; i < npfd; i++) { - int revents = pollfds[i].revents; - - if (revents) { - add_ready_handler(&ready_list, nodes[i], revents); - } - } - } - - npfd = 0; - progress |= aio_bh_poll(ctx); if (ret > 0) { @@ -821,23 +567,15 @@ bool aio_poll(AioContext *ctx, bool blocking) 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 + ctx->fdmon_ops = &fdmon_poll_ops; + ctx->epollfd = -1; + + fdmon_epoll_setup(ctx); } void aio_context_destroy(AioContext *ctx) { -#ifdef CONFIG_EPOLL_CREATE1 - aio_epoll_disable(ctx); -#endif + fdmon_epoll_disable(ctx); } void aio_context_set_poll_params(AioContext *ctx, int64_t max_ns, |