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| author |   Rusty Russell <rusty@rustcorp.com.au> | 2008-02-04 23:49:59 -0500 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2008-02-04 23:50:00 +1100 |
| commit | 426e3e0af5d2473e67d4256fc1340b7faebd1cc7 (patch) | |
| tree | 29912e63889e45307f41ef08116ecd895b17e21c /include/linux/virtio_ring.h | |
| parent | virtio: Fix vring_init/vring_size to take unsigned long (diff) | |
| download | linux-dev-426e3e0af5d2473e67d4256fc1340b7faebd1cc7.tar.xz linux-dev-426e3e0af5d2473e67d4256fc1340b7faebd1cc7.zip | |
virtio: clarify NO_NOTIFY flag usage
The other side (host) can set the NO_NOTIFY flag as an optimization,
to say "no need to kick me when you add things". Make it clear that
this is advisory only; especially that we should always notify when
the ring is full.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'include/linux/virtio_ring.h')
| -rw-r--r-- | include/linux/virtio_ring.h | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h index ea3be89a0e83..abe481ed990e 100644 --- a/include/linux/virtio_ring.h +++ b/include/linux/virtio_ring.h @@ -15,9 +15,13 @@ /* This marks a buffer as write-only (otherwise read-only). */ #define VRING_DESC_F_WRITE 2 -/* This means don't notify other side when buffer added. */ +/* The Host uses this in used->flags to advise the Guest: don't kick me when + * you add a buffer. It's unreliable, so it's simply an optimization. Guest + * will still kick if it's out of buffers. */ #define VRING_USED_F_NO_NOTIFY 1 -/* This means don't interrupt guest when buffer consumed. */ +/* The Guest uses this in avail->flags to advise the Host: don't interrupt me + * when you consume a buffer. It's unreliable, so it's simply an + * optimization. */ #define VRING_AVAIL_F_NO_INTERRUPT 1 /* Virtio ring descriptors: 16 bytes. These can chain together via "next". */ |