[Qemu-devel] [PULL 0/2] xen_disk: use NATIVE_AIO and NOCACHE

[Qemu-devel] [PULL 0/2] xen_disk: use NATIVE_AIO and NOCACHE

[Stefano Stabellini]

Anthony,
please pull this small patch series that allows xen_disk to be used
correctly with NATIVE_AIO and O_DIRECT.

This series should be backported to the stable branch too.


Stefano Stabellini (2):
      xen_disk: open disk with BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO
      xen_disk: when using AIO flush after the operation is completed

 hw/xen_disk.c |   10 +++++-----
 1 files changed, 5 insertions(+), 5 deletions(-)

git://xenbits.xen.org/people/sstabellini/qemu-dm.git disk_io

Cheers,

Stefano

[Qemu-devel] [PATCH 1/2] xen_disk: open disk with BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO

[Stefano Stabellini]

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 hw/xen_disk.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index 68fa36a..0f265a4 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -584,10 +584,10 @@ static int blk_init(struct XenDevice *xendev)
     }
 
     /* read-only ? */
+    qflags = BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO;
     if (strcmp(blkdev->mode, "w") == 0) {
-        qflags = BDRV_O_RDWR;
+        qflags |= BDRV_O_RDWR;
     } else {
-        qflags = 0;
         info  |= VDISK_READONLY;
     }
 
-- 
1.7.2.5

[Qemu-devel] [PATCH 2/2] xen_disk: when using AIO flush after the operation is completed

[Stefano Stabellini]

If ioreq->postsync call bdrv_flush when the AIO operation is actually
completed.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
 hw/xen_disk.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/xen_disk.c b/hw/xen_disk.c
index 0f265a4..9cb0253 100644
--- a/hw/xen_disk.c
+++ b/hw/xen_disk.c
@@ -330,6 +330,9 @@ static void qemu_aio_complete(void *opaque, int ret)
     if (ioreq->aio_inflight > 0) {
         return;
     }
+    if (ioreq->postsync) {
+        bdrv_flush(ioreq->blkdev->bs);
+    }
 
     ioreq->status = ioreq->aio_errors ? BLKIF_RSP_ERROR : BLKIF_RSP_OKAY;
     ioreq_unmap(ioreq);
@@ -376,9 +379,6 @@ static int ioreq_runio_qemu_aio(struct ioreq *ioreq)
         goto err;
     }
 
-    if (ioreq->postsync) {
-        bdrv_flush(blkdev->bs); /* FIXME: aio_flush() ??? */
-    }
     qemu_aio_complete(ioreq, 0);
 
     return 0;
-- 
1.7.2.5

Re: [Qemu-devel] [PULL 0/2] xen_disk: use NATIVE_AIO and NOCACHE

[Christoph Hellwig]

On Tue, Mar 27, 2012 at 04:48:19PM +0100, Stefano Stabellini wrote:
> Anthony,
> please pull this small patch series that allows xen_disk to be used
> correctly with NATIVE_AIO and O_DIRECT.
> 
> This series should be backported to the stable branch too.

Any plans to add BLKIF_OP_FLUSH_DISKCACHE support to xen_disk?  Unlike
the old bnroken Xen barrier scheme this actually implements pure flushes
for fdatasync or blockdevice O_SYNC I/O corectly, and for modern Linux
kernels it actually will be quite a bit faster, too.

Re: [Qemu-devel] [PULL 0/2] xen_disk: use NATIVE_AIO and NOCACHE

[Stefano Stabellini]

On Tue, 27 Mar 2012, Christoph Hellwig wrote:
> On Tue, Mar 27, 2012 at 04:48:19PM +0100, Stefano Stabellini wrote:
> > Anthony,
> > please pull this small patch series that allows xen_disk to be used
> > correctly with NATIVE_AIO and O_DIRECT.
> > 
> > This series should be backported to the stable branch too.
> 
> Any plans to add BLKIF_OP_FLUSH_DISKCACHE support to xen_disk?  Unlike
> the old bnroken Xen barrier scheme this actually implements pure flushes
> for fdatasync or blockdevice O_SYNC I/O corectly, and for modern Linux
> kernels it actually will be quite a bit faster, too.

Yeah, that's a good suggestion, it shouldn't be hard either.

Re: [Qemu-devel] [PULL 0/2] xen_disk: use NATIVE_AIO and NOCACHE

[Anthony Liguori]

On 03/27/2012 10:48 AM, Stefano Stabellini wrote:
> Anthony,
> please pull this small patch series that allows xen_disk to be used
> correctly with NATIVE_AIO and O_DIRECT.
>
> This series should be backported to the stable branch too.

Pulled.  Thanks.

Regards,

Anthony Liguori

>
> Stefano Stabellini (2):
>        xen_disk: open disk with BDRV_O_NOCACHE | BDRV_O_CACHE_WB | BDRV_O_NATIVE_AIO
>        xen_disk: when using AIO flush after the operation is completed
>
>   hw/xen_disk.c |   10 +++++-----
>   1 files changed, 5 insertions(+), 5 deletions(-)
>
> git://xenbits.xen.org/people/sstabellini/qemu-dm.git disk_io
>
> Cheers,
>
> Stefano
>
>