Every laio_io_plug() call has a matching laio_io_unplug() call. There is a plugged counter that tracks the number of levels of plugging and allows for nesting.
The plugged counter must reflect the balance between laio_io_plug() and laio_io_unplug() calls accurately. Otherwise I/O stalls occur since io_submit(2) calls are skipped while plugged. Reported-by: Nikolay Tenev <[email protected]> Signed-off-by: Stefan Hajnoczi <[email protected]> Reviewed-by: Stefano Garzarella <[email protected]> Message-id: [email protected] Cc: Stefano Garzarella <[email protected]> Fixes: 68d7946648 ("linux-aio: add `dev_max_batch` parameter to laio_io_unplug()") [Stefano Garzarella suggested adding a Fixes tag. --Stefan] Signed-off-by: Stefan Hajnoczi <[email protected]> --- block/linux-aio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/linux-aio.c b/block/linux-aio.c index 4c423fcccf..6078da7e42 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -363,8 +363,10 @@ void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s, uint64_t dev_max_batch) { assert(s->io_q.plugged); + s->io_q.plugged--; + if (s->io_q.in_queue >= laio_max_batch(s, dev_max_batch) || - (--s->io_q.plugged == 0 && + (!s->io_q.plugged && !s->io_q.blocked && !QSIMPLEQ_EMPTY(&s->io_q.pending))) { ioq_submit(s); } -- 2.36.1 _______________________________________________ Virtio-fs mailing list [email protected] https://listman.redhat.com/mailman/listinfo/virtio-fs
