diff options
author | Ming Lei <ming.lei@canonical.com> | 2014-07-04 18:04:34 +0800 |
---|---|---|
committer | Stefan Hajnoczi <stefanha@redhat.com> | 2014-07-07 11:05:17 +0200 |
commit | 1b3abdcccf18d98c3952b41be0bc1db3ef6009dd (patch) | |
tree | 207b4496a9ab8fb7d19f7860ba59b52b355efcb7 /block/linux-aio.c | |
parent | 448ad91db4a560c01f89bd6f7e4bec7d869926a5 (diff) | |
download | hqemu-1b3abdcccf18d98c3952b41be0bc1db3ef6009dd.zip hqemu-1b3abdcccf18d98c3952b41be0bc1db3ef6009dd.tar.gz |
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 <ming.lei@canonical.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'block/linux-aio.c')
-rw-r--r-- | block/linux-aio.c | 96 |
1 files changed, 94 insertions, 2 deletions
diff --git a/block/linux-aio.c b/block/linux-aio.c index f0a2c08..4867369 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: |