[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [RFC] block io lost in the guest , possible related to qemu
From: |
Jack Wang |
Subject: |
[Qemu-devel] [RFC] block io lost in the guest , possible related to qemu? |
Date: |
Fri, 25 Oct 2013 17:01:54 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 |
Hi Experts,
We've seen guest block io lost in a VM.any response will be helpful
environment is:
guest os: Ubuntu 1304
running busy database workload with xfs on a disk export with virtio-blk
the exported vdb has very high infight io over 300. Some times later a
lot io process in D state, looks a lot requests is lost in below storage
stack.
We're use qemu-kvm 1.0, host kernel 3.4.51
In qemu log of virtio-blk.c
I found below commit, I wonder is it possible the workload generate some
unknown reqests to qemu that lost in virtio_blk_handle_read?
I do some fio test myself, I cann't generate so call unknown request type.
Any response will be helpful.
Jack
commit 9e72c45033770b81b536ac6091e91807247cc25a
Author: Alexey Zaytsev <address@hidden>
Date: Thu Dec 13 09:03:43 2012 +0200
virtio-blk: Return UNSUPP for unknown request types
Currently, all unknown requests are treated as VIRTIO_BLK_T_IN
Signed-off-by: Alexey Zaytsev <address@hidden>
Signed-off-by: Stefan Hajnoczi <address@hidden>
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index 92c745a..df57b35 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -398,10 +398,14 @@ static void
virtio_blk_handle_request(VirtIOBlockReq *req,
qemu_iovec_init_external(&req->qiov, &req->elem.out_sg[1],
req->elem.out_num - 1);
virtio_blk_handle_write(req, mrb);
- } else {
+ } else if (type == VIRTIO_BLK_T_IN || type == VIRTIO_BLK_T_BARRIER) {
+ /* VIRTIO_BLK_T_IN is 0, so we can't just & it. */
qemu_iovec_init_external(&req->qiov, &req->elem.in_sg[0],
req->elem.in_num - 1);
virtio_blk_handle_read(req);
+ } else {
+ virtio_blk_req_complete(req, VIRTIO_BLK_S_UNSUPP);
+ g_free(req);
}
}
- [Qemu-devel] [RFC] block io lost in the guest , possible related to qemu?,
Jack Wang <=