[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 09/13] hw/xen: do not set is_external=true on evtchn fds
is_external=true suspends fd handlers between aio_disable_external() and aio_enable_external(). The block layer's drain operation uses this mechanism to prevent new I/O from sneaking in between bdrv_drained_begin() and bdrv_drained_end(). The xen-block device actually works fine with is_external=false because BlockBackend requests are already queued between bdrv_drained_begin() and bdrv_drained_end(). Since the Xen ring size is finite, request queuing will stop once the ring is full and memory usage is bounded. After bdrv_drained_end() the BlockBackend requests will resume and xen-block's processing will continue. This is part of ongoing work to remove the aio_disable_external() API. Signed-off-by: Stefan Hajnoczi <stefanha@xxxxxxxxxx> --- hw/xen/xen-bus.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index c59850b1de..c4fd26abe1 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -842,11 +842,11 @@ void xen_device_set_event_channel_context(XenDevice *xendev, } if (channel->ctx) - aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), true, + aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), false, NULL, NULL, NULL, NULL, NULL); channel->ctx = ctx; - aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), true, + aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), false, xen_device_event, NULL, xen_device_poll, NULL, channel); } @@ -920,7 +920,7 @@ void xen_device_unbind_event_channel(XenDevice *xendev, QLIST_REMOVE(channel, list); - aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), true, + aio_set_fd_handler(channel->ctx, qemu_xen_evtchn_fd(channel->xeh), false, NULL, NULL, NULL, NULL, NULL); if (qemu_xen_evtchn_unbind(channel->xeh, channel->local_port) < 0) { -- 2.39.2
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