X-Git-Url: https://repo.jachan.dev/qemu.git/blobdiff_plain/f1a7104a5f435a1bf2a1158e6f737dbd89e8c153..5b4448d27d7c6ff6e18a1edc8245cb1db783e37c:/posix-aio-compat.c diff --git a/posix-aio-compat.c b/posix-aio-compat.c index babb0940dd..d311d13890 100644 --- a/posix-aio-compat.c +++ b/posix-aio-compat.c @@ -9,6 +9,8 @@ * 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 @@ -30,6 +32,7 @@ #include "block/raw-posix-aio.h" +static void do_spawn_thread(void); struct qemu_paiocb { BlockDriverAIOCB common; @@ -41,7 +44,6 @@ struct qemu_paiocb { int aio_niov; size_t aio_nbytes; #define aio_ioctl_cmd aio_nbytes /* for QEMU_AIO_IOCTL */ - int ev_signo; off_t aio_offset; QTAILQ_ENTRY(qemu_paiocb) node; @@ -64,6 +66,9 @@ static pthread_attr_t attr; static int max_threads = 64; static int cur_threads = 0; static int idle_threads = 0; +static int new_threads = 0; /* backlog of threads we need to create */ +static int pending_threads = 0; /* threads created but not running yet */ +static QEMUBH *new_thread_bh; static QTAILQ_HEAD(, qemu_paiocb) request_list; #ifdef CONFIG_PREADV @@ -125,8 +130,8 @@ static ssize_t handle_aiocb_ioctl(struct qemu_paiocb *aiocb) return -errno; /* - * This looks weird, but the aio code only consideres a request - * successful if it has written the number full number of bytes. + * This looks weird, but the aio code only considers a request + * successful if it has written the full number of bytes. * * Now we overload aio_nbytes as aio_ioctl_cmd for the ioctl command, * so in fact we return the ioctl command here to make posix_aio_read() @@ -177,7 +182,6 @@ qemu_pwritev(int fd, const struct iovec *iov, int nr_iov, off_t offset) static ssize_t handle_aiocb_rw_vector(struct qemu_paiocb *aiocb) { - size_t offset = 0; ssize_t len; do { @@ -185,12 +189,12 @@ static ssize_t handle_aiocb_rw_vector(struct qemu_paiocb *aiocb) len = qemu_pwritev(aiocb->aio_fildes, aiocb->aio_iov, aiocb->aio_niov, - aiocb->aio_offset + offset); + aiocb->aio_offset); else len = qemu_preadv(aiocb->aio_fildes, aiocb->aio_iov, aiocb->aio_niov, - aiocb->aio_offset + offset); + aiocb->aio_offset); } while (len == -1 && errno == EINTR); if (len == -1) @@ -305,11 +309,14 @@ static ssize_t handle_aiocb_rw(struct qemu_paiocb *aiocb) return nbytes; } +static void posix_aio_notify_event(void); + static void *aio_thread(void *unused) { - pid_t pid; - - pid = getpid(); + mutex_lock(&lock); + pending_threads--; + mutex_unlock(&lock); + do_spawn_thread(); while (1) { struct qemu_paiocb *aiocb; @@ -372,7 +379,7 @@ static void *aio_thread(void *unused) aiocb->ret = ret; mutex_unlock(&lock); - if (kill(pid, aiocb->ev_signo)) die("kill failed"); + posix_aio_notify_event(); } cur_threads--; @@ -381,11 +388,20 @@ static void *aio_thread(void *unused) return NULL; } -static void spawn_thread(void) +static void do_spawn_thread(void) { sigset_t set, oldset; - cur_threads++; + mutex_lock(&lock); + if (!new_threads) { + mutex_unlock(&lock); + return; + } + + new_threads--; + pending_threads++; + + mutex_unlock(&lock); /* block all signals */ if (sigfillset(&set)) die("sigfillset"); @@ -396,6 +412,27 @@ static void spawn_thread(void) if (sigprocmask(SIG_SETMASK, &oldset, NULL)) die("sigprocmask restore"); } +static void spawn_thread_bh_fn(void *opaque) +{ + do_spawn_thread(); +} + +static void spawn_thread(void) +{ + cur_threads++; + new_threads++; + /* If there are threads being created, they will spawn new workers, so + * we don't spend time creating many threads in a loop holding a mutex or + * starving the current vcpu. + * + * If there are no idle threads, ask the main thread to create one, so we + * inherit the correct affinity instead of the vcpu affinity. + */ + if (!pending_threads) { + qemu_bh_schedule(new_thread_bh); + } +} + static void qemu_paio_submit(struct qemu_paiocb *aiocb) { aiocb->ret = -EINPROGRESS; @@ -509,18 +546,14 @@ static int posix_aio_flush(void *opaque) static PosixAioState *posix_aio_state; -static void aio_signal_handler(int signum) +static void posix_aio_notify_event(void) { - if (posix_aio_state) { - char byte = 0; - ssize_t ret; - - ret = write(posix_aio_state->wfd, &byte, sizeof(byte)); - if (ret < 0 && errno != EAGAIN) - die("write()"); - } + char byte = 0; + ssize_t ret; - qemu_service_io(); + ret = write(posix_aio_state->wfd, &byte, sizeof(byte)); + if (ret < 0 && errno != EAGAIN) + die("write()"); } static void paio_remove(struct qemu_paiocb *acb) @@ -580,11 +613,8 @@ BlockDriverAIOCB *paio_submit(BlockDriverState *bs, int fd, struct qemu_paiocb *acb; acb = qemu_aio_get(&raw_aio_pool, bs, cb, opaque); - if (!acb) - return NULL; acb->aio_type = type; acb->aio_fildes = fd; - acb->ev_signo = SIGUSR2; if (qiov) { acb->aio_iov = qiov->iov; @@ -608,11 +638,8 @@ BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd, struct qemu_paiocb *acb; acb = qemu_aio_get(&raw_aio_pool, bs, cb, opaque); - if (!acb) - return NULL; acb->aio_type = QEMU_AIO_IOCTL; acb->aio_fildes = fd; - acb->ev_signo = SIGUSR2; acb->aio_offset = 0; acb->aio_ioctl_buf = buf; acb->aio_ioctl_cmd = req; @@ -626,7 +653,6 @@ BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd, int paio_init(void) { - struct sigaction act; PosixAioState *s; int fds[2]; int ret; @@ -636,14 +662,10 @@ int paio_init(void) s = g_malloc(sizeof(PosixAioState)); - sigfillset(&act.sa_mask); - act.sa_flags = 0; /* do not restart syscalls to interrupt select() */ - act.sa_handler = aio_signal_handler; - sigaction(SIGUSR2, &act, NULL); - s->first_aio = NULL; if (qemu_pipe(fds) == -1) { fprintf(stderr, "failed to create pipe\n"); + g_free(s); return -1; } @@ -665,6 +687,7 @@ int paio_init(void) die2(ret, "pthread_attr_setdetachstate"); QTAILQ_INIT(&request_list); + new_thread_bh = qemu_bh_new(spawn_thread_bh_fn, NULL); posix_aio_state = s; return 0;