Il 04/09/2012 22:11, Nicholas A. Bellinger ha scritto:
As tgt-tgt_lock is taken in virtscsi_queuecommand_multi() before the
atomic_inc_return(tgt-reqs) check, it seems like using atomic_dec() w/o
smp_mb__after_atomic_dec or tgt_lock access here is not using atomic.h
accessors properly, no..?
Il 04/09/2012 04:21, Nicholas A. Bellinger ha scritto:
@@ -112,6 +118,9 @@ static void virtscsi_complete_cmd(struct virtio_scsi
*vscsi, void *buf)
struct virtio_scsi_cmd *cmd = buf;
struct scsi_cmnd *sc = cmd-sc;
struct virtio_scsi_cmd_resp *resp = cmd-resp.cmd;
+struct
On Tue, Sep 04, 2012 at 08:46:12AM +0200, Paolo Bonzini wrote:
Il 04/09/2012 04:21, Nicholas A. Bellinger ha scritto:
@@ -112,6 +118,9 @@ static void virtscsi_complete_cmd(struct virtio_scsi
*vscsi, void *buf)
struct virtio_scsi_cmd *cmd = buf;
struct scsi_cmnd *sc = cmd-sc;
Il 04/09/2012 10:46, Michael S. Tsirkin ha scritto:
+static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
+ struct scsi_cmnd *sc)
+{
+ struct virtio_scsi *vscsi = shost_priv(sh);
+ struct virtio_scsi_target_state *tgt = vscsi-tgt[sc-device-id];
+
On Tue, Sep 04, 2012 at 12:25:03PM +0200, Paolo Bonzini wrote:
Il 04/09/2012 10:46, Michael S. Tsirkin ha scritto:
+static int virtscsi_queuecommand_multi(struct Scsi_Host *sh,
+ struct scsi_cmnd *sc)
+{
+struct virtio_scsi *vscsi =
Il 04/09/2012 13:09, Michael S. Tsirkin ha scritto:
queuecommand on CPU #0 queuecommand #2 on CPU #1
--
atomic_inc_return(...) == 1
atomic_inc_return(...) == 2
On Tue, Aug 28, 2012 at 01:54:17PM +0200, Paolo Bonzini wrote:
This patch adds queue steering to virtio-scsi. When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept. However, if a target was idle, we can choose
a queue
On Tue, Sep 04, 2012 at 01:18:31PM +0200, Paolo Bonzini wrote:
Il 04/09/2012 13:09, Michael S. Tsirkin ha scritto:
queuecommand on CPU #0 queuecommand #2 on CPU #1
--
atomic_inc_return(...) == 1
Il 04/09/2012 15:35, Michael S. Tsirkin ha scritto:
I see. I guess you can rewrite this as:
atomic_inc
if (atomic_read() == 1)
which is a bit cheaper, and make the fact
that you do not need increment and return to be atomic,
explicit.
It seems more complicated to me for hardly any reason.
Il 04/09/2012 14:48, Michael S. Tsirkin ha scritto:
This patch adds queue steering to virtio-scsi. When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept. However, if a target was idle, we can choose
a queue arbitrarily. In
On Tue, Sep 04, 2012 at 03:45:57PM +0200, Paolo Bonzini wrote:
Also - some kind of comment explaining why a similar race can not happen
with this lock in place would be nice: I see why this specific race can
not trigger but since lock is dropped later before you submit command, I
have hard
On Tue, Sep 04, 2012 at 03:49:42PM +0200, Paolo Bonzini wrote:
Il 04/09/2012 14:48, Michael S. Tsirkin ha scritto:
This patch adds queue steering to virtio-scsi. When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept.
Il 04/09/2012 16:19, Michael S. Tsirkin ha scritto:
Also - some kind of comment explaining why a similar race can not happen
with this lock in place would be nice: I see why this specific race can
not trigger but since lock is dropped later before you submit command, I
have hard time
Il 04/09/2012 16:21, Michael S. Tsirkin ha scritto:
One reason is that, even though in practice I expect roughly the same
number of targets and VCPUs, hotplug means the number of targets is
difficult to predict and is usually fixed to 256.
The other reason is that per-target vq didn't
On Tue, Sep 04, 2012 at 04:30:35PM +0200, Paolo Bonzini wrote:
Il 04/09/2012 16:21, Michael S. Tsirkin ha scritto:
One reason is that, even though in practice I expect roughly the same
number of targets and VCPUs, hotplug means the number of targets is
difficult to predict and is usually
On Tue, Aug 28, 2012 at 01:54:17PM +0200, Paolo Bonzini wrote:
@@ -575,15 +630,19 @@ static struct scsi_host_template virtscsi_host_template
= {
__val, sizeof(__val)); \
})
+
Pls don't add empty lines.
static void virtscsi_init_vq(struct
Il 04/09/2012 16:47, Michael S. Tsirkin ha scritto:
static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
- struct virtqueue *vq)
+ struct virtqueue *vq, bool affinity)
{
spin_lock_init(virtscsi_vq-vq_lock);
virtscsi_vq-vq
On Tue, Sep 04, 2012 at 04:55:56PM +0200, Paolo Bonzini wrote:
Il 04/09/2012 16:47, Michael S. Tsirkin ha scritto:
static void virtscsi_init_vq(struct virtio_scsi_vq *virtscsi_vq,
- struct virtqueue *vq)
+ struct virtqueue *vq,
On Tue, 2012-09-04 at 08:46 +0200, Paolo Bonzini wrote:
Il 04/09/2012 04:21, Nicholas A. Bellinger ha scritto:
@@ -112,6 +118,9 @@ static void virtscsi_complete_cmd(struct virtio_scsi
*vscsi, void *buf)
struct virtio_scsi_cmd *cmd = buf;
struct scsi_cmnd *sc = cmd-sc;
struct
On Tue, 2012-08-28 at 13:54 +0200, Paolo Bonzini wrote:
This patch adds queue steering to virtio-scsi. When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept. However, if a target was idle, we can choose
a queue arbitrarily. In
This patch adds queue steering to virtio-scsi. When a target is sent
multiple requests, we always drive them to the same queue so that FIFO
processing order is kept. However, if a target was idle, we can choose
a queue arbitrarily. In this case the queue is chosen according to the
current VCPU,
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