From 1b3abdcccf18d98c3952b41be0bc1db3ef6009dd Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Fri, 4 Jul 2014 18:04:34 +0800 Subject: [PATCH] linux-aio: implement io plug, unplug and flush io queue This patch implements .bdrv_io_plug, .bdrv_io_unplug and .bdrv_flush_io_queue callbacks for linux-aio Block Drivers, so that submitting I/O as a batch can be supported on linux-aio. [Unprocessed requests are completed with -EIO instead of a bogus ret value. --Stefan] Signed-off-by: Ming Lei Signed-off-by: Stefan Hajnoczi --- block/linux-aio.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++++++++-- block/raw-aio.h | 2 ++ block/raw-posix.c | 45 ++++++++++++++++++++++++++ 3 files changed, 141 insertions(+), 2 deletions(-) diff --git a/block/linux-aio.c b/block/linux-aio.c index f0a2c087b2..48673690ac 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -25,6 +25,8 @@ */ #define MAX_EVENTS 128 +#define MAX_QUEUED_IO 128 + struct qemu_laiocb { BlockDriverAIOCB common; struct qemu_laio_state *ctx; @@ -36,9 +38,19 @@ struct qemu_laiocb { QLIST_ENTRY(qemu_laiocb) node; }; +typedef struct { + struct iocb *iocbs[MAX_QUEUED_IO]; + int plugged; + unsigned int size; + unsigned int idx; +} LaioQueue; + struct qemu_laio_state { io_context_t ctx; EventNotifier e; + + /* io queue for submit at batch */ + LaioQueue io_q; }; static inline ssize_t io_event_ret(struct io_event *ev) @@ -135,6 +147,79 @@ static const AIOCBInfo laio_aiocb_info = { .cancel = laio_cancel, }; +static void ioq_init(LaioQueue *io_q) +{ + io_q->size = MAX_QUEUED_IO; + io_q->idx = 0; + io_q->plugged = 0; +} + +static int ioq_submit(struct qemu_laio_state *s) +{ + int ret, i = 0; + int len = s->io_q.idx; + + do { + ret = io_submit(s->ctx, len, s->io_q.iocbs); + } while (i++ < 3 && ret == -EAGAIN); + + /* empty io queue */ + s->io_q.idx = 0; + + if (ret < 0) { + i = 0; + } else { + i = ret; + } + + for (; i < len; i++) { + struct qemu_laiocb *laiocb = + container_of(s->io_q.iocbs[i], struct qemu_laiocb, iocb); + + laiocb->ret = (ret < 0) ? ret : -EIO; + qemu_laio_process_completion(s, laiocb); + } + return ret; +} + +static void ioq_enqueue(struct qemu_laio_state *s, struct iocb *iocb) +{ + unsigned int idx = s->io_q.idx; + + s->io_q.iocbs[idx++] = iocb; + s->io_q.idx = idx; + + /* submit immediately if queue is full */ + if (idx == s->io_q.size) { + ioq_submit(s); + } +} + +void laio_io_plug(BlockDriverState *bs, void *aio_ctx) +{ + struct qemu_laio_state *s = aio_ctx; + + s->io_q.plugged++; +} + +int laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug) +{ + struct qemu_laio_state *s = aio_ctx; + int ret = 0; + + assert(s->io_q.plugged > 0 || !unplug); + + if (unplug && --s->io_q.plugged > 0) { + return 0; + } + + if (s->io_q.idx > 0) { + ret = ioq_submit(s); + } + + return ret; +} + BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque, int type) @@ -168,8 +253,13 @@ BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd, } io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e)); - if (io_submit(s->ctx, 1, &iocbs) < 0) - goto out_free_aiocb; + if (!s->io_q.plugged) { + if (io_submit(s->ctx, 1, &iocbs) < 0) { + goto out_free_aiocb; + } + } else { + ioq_enqueue(s, iocbs); + } return &laiocb->common; out_free_aiocb: @@ -204,6 +294,8 @@ void *laio_init(void) goto out_close_efd; } + ioq_init(&s->io_q); + return s; out_close_efd: diff --git a/block/raw-aio.h b/block/raw-aio.h index 8cf084eeb5..e18c97509a 100644 --- a/block/raw-aio.h +++ b/block/raw-aio.h @@ -40,6 +40,8 @@ BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd, BlockDriverCompletionFunc *cb, void *opaque, int type); void laio_detach_aio_context(void *s, AioContext *old_context); void laio_attach_aio_context(void *s, AioContext *new_context); +void laio_io_plug(BlockDriverState *bs, void *aio_ctx); +int laio_io_unplug(BlockDriverState *bs, void *aio_ctx, bool unplug); #endif #ifdef _WIN32 diff --git a/block/raw-posix.c b/block/raw-posix.c index fa005b38b7..a857def671 100644 --- a/block/raw-posix.c +++ b/block/raw-posix.c @@ -1057,6 +1057,36 @@ static BlockDriverAIOCB *raw_aio_submit(BlockDriverState *bs, cb, opaque, type); } +static void raw_aio_plug(BlockDriverState *bs) +{ +#ifdef CONFIG_LINUX_AIO + BDRVRawState *s = bs->opaque; + if (s->use_aio) { + laio_io_plug(bs, s->aio_ctx); + } +#endif +} + +static void raw_aio_unplug(BlockDriverState *bs) +{ +#ifdef CONFIG_LINUX_AIO + BDRVRawState *s = bs->opaque; + if (s->use_aio) { + laio_io_unplug(bs, s->aio_ctx, true); + } +#endif +} + +static void raw_aio_flush_io_queue(BlockDriverState *bs) +{ +#ifdef CONFIG_LINUX_AIO + BDRVRawState *s = bs->opaque; + if (s->use_aio) { + laio_io_unplug(bs, s->aio_ctx, false); + } +#endif +} + static BlockDriverAIOCB *raw_aio_readv(BlockDriverState *bs, int64_t sector_num, QEMUIOVector *qiov, int nb_sectors, BlockDriverCompletionFunc *cb, void *opaque) @@ -1544,6 +1574,9 @@ static BlockDriver bdrv_file = { .bdrv_aio_flush = raw_aio_flush, .bdrv_aio_discard = raw_aio_discard, .bdrv_refresh_limits = raw_refresh_limits, + .bdrv_io_plug = raw_aio_plug, + .bdrv_io_unplug = raw_aio_unplug, + .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -1943,6 +1976,9 @@ static BlockDriver bdrv_host_device = { .bdrv_aio_flush = raw_aio_flush, .bdrv_aio_discard = hdev_aio_discard, .bdrv_refresh_limits = raw_refresh_limits, + .bdrv_io_plug = raw_aio_plug, + .bdrv_io_unplug = raw_aio_unplug, + .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -2088,6 +2124,9 @@ static BlockDriver bdrv_host_floppy = { .bdrv_aio_writev = raw_aio_writev, .bdrv_aio_flush = raw_aio_flush, .bdrv_refresh_limits = raw_refresh_limits, + .bdrv_io_plug = raw_aio_plug, + .bdrv_io_unplug = raw_aio_unplug, + .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -2216,6 +2255,9 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_aio_writev = raw_aio_writev, .bdrv_aio_flush = raw_aio_flush, .bdrv_refresh_limits = raw_refresh_limits, + .bdrv_io_plug = raw_aio_plug, + .bdrv_io_unplug = raw_aio_unplug, + .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, @@ -2350,6 +2392,9 @@ static BlockDriver bdrv_host_cdrom = { .bdrv_aio_writev = raw_aio_writev, .bdrv_aio_flush = raw_aio_flush, .bdrv_refresh_limits = raw_refresh_limits, + .bdrv_io_plug = raw_aio_plug, + .bdrv_io_unplug = raw_aio_unplug, + .bdrv_flush_io_queue = raw_aio_flush_io_queue, .bdrv_truncate = raw_truncate, .bdrv_getlength = raw_getlength, -- 2.11.0