Re: [PATCH v4 05/10] xen/blkfront: negotiate number of queues/rings to be used with backend
On Wed, Nov 04, 2015 at 09:11:10AM +0800, Bob Liu wrote:
>
> On 11/04/2015 04:40 AM, Konrad Rzeszutek Wilk wrote:
> > On Mon, Nov 02, 2015 at 12:21:41PM +0800, Bob Liu wrote:
> >> The number of hardware queues for xen/blkfront is set by parameter
> >> 'max_queues'(default 4), while the max value xen/blkback supported is
> >> notified
> >> through xenstore("multi-queue-max-queues").
> >
> > That is not right.
> >
> > s/The number/The max number/
> >
> > The second part: ",while the max value xen/blkback supported is..". I think
> > you are trying to say: "it is also capped by the max value that
> > the xen/blkback exposes through XenStore key 'multi-queue-max-queues'.
> >
> >>
> >> The negotiated number is the smaller one and would be written back to
> >> xenstore
> >> as "multi-queue-num-queues", blkback need to read this negotiated number.
> >
> > s/blkback need to read/blkback needs to read this/
> >
> >>
> >> Signed-off-by: Bob Liu
> >> ---
> >> drivers/block/xen-blkfront.c | 166
> >> +++
> >> 1 file changed, 120 insertions(+), 46 deletions(-)
> >>
> >> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> >> index 8cc5995..23096d7 100644
> >> --- a/drivers/block/xen-blkfront.c
> >> +++ b/drivers/block/xen-blkfront.c
> >> @@ -98,6 +98,10 @@ static unsigned int xen_blkif_max_segments = 32;
> >> module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
> >> MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests
> >> (default is 32)");
> >>
> >> +static unsigned int xen_blkif_max_queues = 4;
> >> +module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
> >> +MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings
> >> used per virtual disk");
> >> +
> >> /*
> >> * Maximum order of pages to be used for the shared ring between front and
> >> * backend, 4KB page granularity is used.
> >> @@ -113,6 +117,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order
> >> of pages to be used for the
> >> * characters are enough. Define to 20 to keep consist with backend.
> >> */
> >> #define RINGREF_NAME_LEN (20)
> >> +#define QUEUE_NAME_LEN (12)
> >
> > Little bit of documentation please. Why 12? Why not 31415 for example?
> > I presume it is 'queue-%u' and since so that is 7 + 10 (UINT_MAX is
> > 4294967295) = 17!
> >
> >
> >>
> >> /*
> >> * Per-ring info.
> >> @@ -695,7 +700,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd,
> >> u16 sector_size,
> >>
> >>memset(>tag_set, 0, sizeof(info->tag_set));
> >>info->tag_set.ops = _mq_ops;
> >> - info->tag_set.nr_hw_queues = 1;
> >> + info->tag_set.nr_hw_queues = info->nr_rings;
> >>info->tag_set.queue_depth = BLK_RING_SIZE(info);
> >>info->tag_set.numa_node = NUMA_NO_NODE;
> >>info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
> >> @@ -1352,6 +1357,51 @@ fail:
> >>return err;
> >> }
> >>
> >> +static int write_per_ring_nodes(struct xenbus_transaction xbt,
> >> + struct blkfront_ring_info *rinfo, const char
> >> *dir)
> >> +{
> >> + int err, i;
> >
> > Please make 'i' be an unsigned int. Especially as you are using '%u' in the
> > snprintf.
> >
> >
> >> + const char *message = NULL;
> >> + struct blkfront_info *info = rinfo->dev_info;
> >> +
> >> + if (info->nr_ring_pages == 1) {
> >> + err = xenbus_printf(xbt, dir, "ring-ref", "%u",
> >> rinfo->ring_ref[0]);
> >> + if (err) {
> >> + message = "writing ring-ref";
> >> + goto abort_transaction;
> >> + }
> >> + pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]);
> >
> > Ewww. No.
> >
> >> + } else {
> >> + for (i = 0; i < info->nr_ring_pages; i++) {
> >> + char ring_ref_name[RINGREF_NAME_LEN];
> >> +
> >> + snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u",
> >> i);
> >> + err = xenbus_printf(xbt, dir, ring_ref_name,
> >> + "%u", rinfo->ring_ref[i]);
> >> + if (err) {
> >> + message = "writing ring-ref";
> >> + goto abort_transaction;
> >> + }
> >> + pr_info("%s: write ring-ref:%d\n", dir,
> >> rinfo->ring_ref[i]);
> >
> > No no please.
> >
> >> + }
> >> + }
> >> +
> >> + err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
> >
> > That is not right.
> >
> > That only creates one. But the blkif.h says (And the example agrees)
> > that there are N 'event-channel' for N-rings.
> >
> > Shouldn't this be part of the above loop?
> >
>
> No, this loop is only for per-ring each with "multipage".
>
> The loop you want is..
>
> >> + if (err) {
> >> + message = "writing event-channel";
> >> + goto abort_transaction;
> >> + }
> >> + pr_info("%s: write
Re: [PATCH v4 05/10] xen/blkfront: negotiate number of queues/rings to be used with backend
On 11/04/2015 04:40 AM, Konrad Rzeszutek Wilk wrote:
> On Mon, Nov 02, 2015 at 12:21:41PM +0800, Bob Liu wrote:
>> The number of hardware queues for xen/blkfront is set by parameter
>> 'max_queues'(default 4), while the max value xen/blkback supported is
>> notified
>> through xenstore("multi-queue-max-queues").
>
> That is not right.
>
> s/The number/The max number/
>
> The second part: ",while the max value xen/blkback supported is..". I think
> you are trying to say: "it is also capped by the max value that
> the xen/blkback exposes through XenStore key 'multi-queue-max-queues'.
>
>>
>> The negotiated number is the smaller one and would be written back to
>> xenstore
>> as "multi-queue-num-queues", blkback need to read this negotiated number.
>
> s/blkback need to read/blkback needs to read this/
>
>>
>> Signed-off-by: Bob Liu
>> ---
>> drivers/block/xen-blkfront.c | 166
>> +++
>> 1 file changed, 120 insertions(+), 46 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
>> index 8cc5995..23096d7 100644
>> --- a/drivers/block/xen-blkfront.c
>> +++ b/drivers/block/xen-blkfront.c
>> @@ -98,6 +98,10 @@ static unsigned int xen_blkif_max_segments = 32;
>> module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
>> MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests
>> (default is 32)");
>>
>> +static unsigned int xen_blkif_max_queues = 4;
>> +module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
>> +MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used
>> per virtual disk");
>> +
>> /*
>> * Maximum order of pages to be used for the shared ring between front and
>> * backend, 4KB page granularity is used.
>> @@ -113,6 +117,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of
>> pages to be used for the
>> * characters are enough. Define to 20 to keep consist with backend.
>> */
>> #define RINGREF_NAME_LEN (20)
>> +#define QUEUE_NAME_LEN (12)
>
> Little bit of documentation please. Why 12? Why not 31415 for example?
> I presume it is 'queue-%u' and since so that is 7 + 10 (UINT_MAX is
> 4294967295) = 17!
>
>
>>
>> /*
>> * Per-ring info.
>> @@ -695,7 +700,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16
>> sector_size,
>>
>> memset(>tag_set, 0, sizeof(info->tag_set));
>> info->tag_set.ops = _mq_ops;
>> -info->tag_set.nr_hw_queues = 1;
>> +info->tag_set.nr_hw_queues = info->nr_rings;
>> info->tag_set.queue_depth = BLK_RING_SIZE(info);
>> info->tag_set.numa_node = NUMA_NO_NODE;
>> info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
>> @@ -1352,6 +1357,51 @@ fail:
>> return err;
>> }
>>
>> +static int write_per_ring_nodes(struct xenbus_transaction xbt,
>> +struct blkfront_ring_info *rinfo, const char
>> *dir)
>> +{
>> +int err, i;
>
> Please make 'i' be an unsigned int. Especially as you are using '%u' in the
> snprintf.
>
>
>> +const char *message = NULL;
>> +struct blkfront_info *info = rinfo->dev_info;
>> +
>> +if (info->nr_ring_pages == 1) {
>> +err = xenbus_printf(xbt, dir, "ring-ref", "%u",
>> rinfo->ring_ref[0]);
>> +if (err) {
>> +message = "writing ring-ref";
>> +goto abort_transaction;
>> +}
>> +pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]);
>
> Ewww. No.
>
>> +} else {
>> +for (i = 0; i < info->nr_ring_pages; i++) {
>> +char ring_ref_name[RINGREF_NAME_LEN];
>> +
>> +snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u",
>> i);
>> +err = xenbus_printf(xbt, dir, ring_ref_name,
>> +"%u", rinfo->ring_ref[i]);
>> +if (err) {
>> +message = "writing ring-ref";
>> +goto abort_transaction;
>> +}
>> +pr_info("%s: write ring-ref:%d\n", dir,
>> rinfo->ring_ref[i]);
>
> No no please.
>
>> +}
>> +}
>> +
>> +err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
>
> That is not right.
>
> That only creates one. But the blkif.h says (And the example agrees)
> that there are N 'event-channel' for N-rings.
>
> Shouldn't this be part of the above loop?
>
No, this loop is only for per-ring each with "multipage".
The loop you want is..
>> +if (err) {
>> +message = "writing event-channel";
>> +goto abort_transaction;
>> +}
>> +pr_info("%s: write event-channel:%d\n", dir, rinfo->evtchn);
>
> Please no.
>
>> +
>> +return 0;
>> +
>> +abort_transaction:
>> +xenbus_transaction_end(xbt, 1);
>> +if (message)
>> +xenbus_dev_fatal(info->xbdev, err, "%s", message);
>> +
>> +return err;
>> +}
>>
Re: [PATCH v4 05/10] xen/blkfront: negotiate number of queues/rings to be used with backend
On 11/04/2015 04:40 AM, Konrad Rzeszutek Wilk wrote:
> On Mon, Nov 02, 2015 at 12:21:41PM +0800, Bob Liu wrote:
>> The number of hardware queues for xen/blkfront is set by parameter
>> 'max_queues'(default 4), while the max value xen/blkback supported is
>> notified
>> through xenstore("multi-queue-max-queues").
>
> That is not right.
>
> s/The number/The max number/
>
> The second part: ",while the max value xen/blkback supported is..". I think
> you are trying to say: "it is also capped by the max value that
> the xen/blkback exposes through XenStore key 'multi-queue-max-queues'.
>
>>
>> The negotiated number is the smaller one and would be written back to
>> xenstore
>> as "multi-queue-num-queues", blkback need to read this negotiated number.
>
> s/blkback need to read/blkback needs to read this/
>
>>
>> Signed-off-by: Bob Liu
>> ---
>> drivers/block/xen-blkfront.c | 166
>> +++
>> 1 file changed, 120 insertions(+), 46 deletions(-)
>>
>> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
>> index 8cc5995..23096d7 100644
>> --- a/drivers/block/xen-blkfront.c
>> +++ b/drivers/block/xen-blkfront.c
>> @@ -98,6 +98,10 @@ static unsigned int xen_blkif_max_segments = 32;
>> module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
>> MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests
>> (default is 32)");
>>
>> +static unsigned int xen_blkif_max_queues = 4;
>> +module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
>> +MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used
>> per virtual disk");
>> +
>> /*
>> * Maximum order of pages to be used for the shared ring between front and
>> * backend, 4KB page granularity is used.
>> @@ -113,6 +117,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of
>> pages to be used for the
>> * characters are enough. Define to 20 to keep consist with backend.
>> */
>> #define RINGREF_NAME_LEN (20)
>> +#define QUEUE_NAME_LEN (12)
>
> Little bit of documentation please. Why 12? Why not 31415 for example?
> I presume it is 'queue-%u' and since so that is 7 + 10 (UINT_MAX is
> 4294967295) = 17!
>
>
>>
>> /*
>> * Per-ring info.
>> @@ -695,7 +700,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16
>> sector_size,
>>
>> memset(>tag_set, 0, sizeof(info->tag_set));
>> info->tag_set.ops = _mq_ops;
>> -info->tag_set.nr_hw_queues = 1;
>> +info->tag_set.nr_hw_queues = info->nr_rings;
>> info->tag_set.queue_depth = BLK_RING_SIZE(info);
>> info->tag_set.numa_node = NUMA_NO_NODE;
>> info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
>> @@ -1352,6 +1357,51 @@ fail:
>> return err;
>> }
>>
>> +static int write_per_ring_nodes(struct xenbus_transaction xbt,
>> +struct blkfront_ring_info *rinfo, const char
>> *dir)
>> +{
>> +int err, i;
>
> Please make 'i' be an unsigned int. Especially as you are using '%u' in the
> snprintf.
>
>
>> +const char *message = NULL;
>> +struct blkfront_info *info = rinfo->dev_info;
>> +
>> +if (info->nr_ring_pages == 1) {
>> +err = xenbus_printf(xbt, dir, "ring-ref", "%u",
>> rinfo->ring_ref[0]);
>> +if (err) {
>> +message = "writing ring-ref";
>> +goto abort_transaction;
>> +}
>> +pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]);
>
> Ewww. No.
>
>> +} else {
>> +for (i = 0; i < info->nr_ring_pages; i++) {
>> +char ring_ref_name[RINGREF_NAME_LEN];
>> +
>> +snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u",
>> i);
>> +err = xenbus_printf(xbt, dir, ring_ref_name,
>> +"%u", rinfo->ring_ref[i]);
>> +if (err) {
>> +message = "writing ring-ref";
>> +goto abort_transaction;
>> +}
>> +pr_info("%s: write ring-ref:%d\n", dir,
>> rinfo->ring_ref[i]);
>
> No no please.
>
>> +}
>> +}
>> +
>> +err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
>
> That is not right.
>
> That only creates one. But the blkif.h says (And the example agrees)
> that there are N 'event-channel' for N-rings.
>
> Shouldn't this be part of the above loop?
>
No, this loop is only for per-ring each with "multipage".
The loop you want is..
>> +if (err) {
>> +message = "writing event-channel";
>> +goto abort_transaction;
>> +}
>> +pr_info("%s: write event-channel:%d\n", dir, rinfo->evtchn);
>
> Please no.
>
>> +
>> +return 0;
>> +
>> +abort_transaction:
>> +xenbus_transaction_end(xbt, 1);
>> +if (message)
>> +xenbus_dev_fatal(info->xbdev, err, "%s", message);
>> +
>> +
Re: [PATCH v4 05/10] xen/blkfront: negotiate number of queues/rings to be used with backend
On Wed, Nov 04, 2015 at 09:11:10AM +0800, Bob Liu wrote:
>
> On 11/04/2015 04:40 AM, Konrad Rzeszutek Wilk wrote:
> > On Mon, Nov 02, 2015 at 12:21:41PM +0800, Bob Liu wrote:
> >> The number of hardware queues for xen/blkfront is set by parameter
> >> 'max_queues'(default 4), while the max value xen/blkback supported is
> >> notified
> >> through xenstore("multi-queue-max-queues").
> >
> > That is not right.
> >
> > s/The number/The max number/
> >
> > The second part: ",while the max value xen/blkback supported is..". I think
> > you are trying to say: "it is also capped by the max value that
> > the xen/blkback exposes through XenStore key 'multi-queue-max-queues'.
> >
> >>
> >> The negotiated number is the smaller one and would be written back to
> >> xenstore
> >> as "multi-queue-num-queues", blkback need to read this negotiated number.
> >
> > s/blkback need to read/blkback needs to read this/
> >
> >>
> >> Signed-off-by: Bob Liu
> >> ---
> >> drivers/block/xen-blkfront.c | 166
> >> +++
> >> 1 file changed, 120 insertions(+), 46 deletions(-)
> >>
> >> diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
> >> index 8cc5995..23096d7 100644
> >> --- a/drivers/block/xen-blkfront.c
> >> +++ b/drivers/block/xen-blkfront.c
> >> @@ -98,6 +98,10 @@ static unsigned int xen_blkif_max_segments = 32;
> >> module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
> >> MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests
> >> (default is 32)");
> >>
> >> +static unsigned int xen_blkif_max_queues = 4;
> >> +module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
> >> +MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings
> >> used per virtual disk");
> >> +
> >> /*
> >> * Maximum order of pages to be used for the shared ring between front and
> >> * backend, 4KB page granularity is used.
> >> @@ -113,6 +117,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order
> >> of pages to be used for the
> >> * characters are enough. Define to 20 to keep consist with backend.
> >> */
> >> #define RINGREF_NAME_LEN (20)
> >> +#define QUEUE_NAME_LEN (12)
> >
> > Little bit of documentation please. Why 12? Why not 31415 for example?
> > I presume it is 'queue-%u' and since so that is 7 + 10 (UINT_MAX is
> > 4294967295) = 17!
> >
> >
> >>
> >> /*
> >> * Per-ring info.
> >> @@ -695,7 +700,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd,
> >> u16 sector_size,
> >>
> >>memset(>tag_set, 0, sizeof(info->tag_set));
> >>info->tag_set.ops = _mq_ops;
> >> - info->tag_set.nr_hw_queues = 1;
> >> + info->tag_set.nr_hw_queues = info->nr_rings;
> >>info->tag_set.queue_depth = BLK_RING_SIZE(info);
> >>info->tag_set.numa_node = NUMA_NO_NODE;
> >>info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
> >> @@ -1352,6 +1357,51 @@ fail:
> >>return err;
> >> }
> >>
> >> +static int write_per_ring_nodes(struct xenbus_transaction xbt,
> >> + struct blkfront_ring_info *rinfo, const char
> >> *dir)
> >> +{
> >> + int err, i;
> >
> > Please make 'i' be an unsigned int. Especially as you are using '%u' in the
> > snprintf.
> >
> >
> >> + const char *message = NULL;
> >> + struct blkfront_info *info = rinfo->dev_info;
> >> +
> >> + if (info->nr_ring_pages == 1) {
> >> + err = xenbus_printf(xbt, dir, "ring-ref", "%u",
> >> rinfo->ring_ref[0]);
> >> + if (err) {
> >> + message = "writing ring-ref";
> >> + goto abort_transaction;
> >> + }
> >> + pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]);
> >
> > Ewww. No.
> >
> >> + } else {
> >> + for (i = 0; i < info->nr_ring_pages; i++) {
> >> + char ring_ref_name[RINGREF_NAME_LEN];
> >> +
> >> + snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u",
> >> i);
> >> + err = xenbus_printf(xbt, dir, ring_ref_name,
> >> + "%u", rinfo->ring_ref[i]);
> >> + if (err) {
> >> + message = "writing ring-ref";
> >> + goto abort_transaction;
> >> + }
> >> + pr_info("%s: write ring-ref:%d\n", dir,
> >> rinfo->ring_ref[i]);
> >
> > No no please.
> >
> >> + }
> >> + }
> >> +
> >> + err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
> >
> > That is not right.
> >
> > That only creates one. But the blkif.h says (And the example agrees)
> > that there are N 'event-channel' for N-rings.
> >
> > Shouldn't this be part of the above loop?
> >
>
> No, this loop is only for per-ring each with "multipage".
>
> The loop you want is..
>
> >> + if (err) {
> >> + message = "writing event-channel";
> >> + goto abort_transaction;
> >> + }
> >> + pr_info("%s:
[PATCH v4 05/10] xen/blkfront: negotiate number of queues/rings to be used with backend
The number of hardware queues for xen/blkfront is set by parameter
'max_queues'(default 4), while the max value xen/blkback supported is notified
through xenstore("multi-queue-max-queues").
The negotiated number is the smaller one and would be written back to xenstore
as "multi-queue-num-queues", blkback need to read this negotiated number.
Signed-off-by: Bob Liu
---
drivers/block/xen-blkfront.c | 166 +++
1 file changed, 120 insertions(+), 46 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8cc5995..23096d7 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -98,6 +98,10 @@ static unsigned int xen_blkif_max_segments = 32;
module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests
(default is 32)");
+static unsigned int xen_blkif_max_queues = 4;
+module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
+MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per
virtual disk");
+
/*
* Maximum order of pages to be used for the shared ring between front and
* backend, 4KB page granularity is used.
@@ -113,6 +117,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of
pages to be used for the
* characters are enough. Define to 20 to keep consist with backend.
*/
#define RINGREF_NAME_LEN (20)
+#define QUEUE_NAME_LEN (12)
/*
* Per-ring info.
@@ -695,7 +700,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16
sector_size,
memset(>tag_set, 0, sizeof(info->tag_set));
info->tag_set.ops = _mq_ops;
- info->tag_set.nr_hw_queues = 1;
+ info->tag_set.nr_hw_queues = info->nr_rings;
info->tag_set.queue_depth = BLK_RING_SIZE(info);
info->tag_set.numa_node = NUMA_NO_NODE;
info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
@@ -1352,6 +1357,51 @@ fail:
return err;
}
+static int write_per_ring_nodes(struct xenbus_transaction xbt,
+ struct blkfront_ring_info *rinfo, const char
*dir)
+{
+ int err, i;
+ const char *message = NULL;
+ struct blkfront_info *info = rinfo->dev_info;
+
+ if (info->nr_ring_pages == 1) {
+ err = xenbus_printf(xbt, dir, "ring-ref", "%u",
rinfo->ring_ref[0]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]);
+ } else {
+ for (i = 0; i < info->nr_ring_pages; i++) {
+ char ring_ref_name[RINGREF_NAME_LEN];
+
+ snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u",
i);
+ err = xenbus_printf(xbt, dir, ring_ref_name,
+ "%u", rinfo->ring_ref[i]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ pr_info("%s: write ring-ref:%d\n", dir,
rinfo->ring_ref[i]);
+ }
+ }
+
+ err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
+ if (err) {
+ message = "writing event-channel";
+ goto abort_transaction;
+ }
+ pr_info("%s: write event-channel:%d\n", dir, rinfo->evtchn);
+
+ return 0;
+
+abort_transaction:
+ xenbus_transaction_end(xbt, 1);
+ if (message)
+ xenbus_dev_fatal(info->xbdev, err, "%s", message);
+
+ return err;
+}
/* Common code used when first setting up, and when resuming. */
static int talk_to_blkback(struct xenbus_device *dev,
@@ -1362,7 +1412,6 @@ static int talk_to_blkback(struct xenbus_device *dev,
int err, i;
unsigned int max_page_order = 0;
unsigned int ring_page_order = 0;
- struct blkfront_ring_info *rinfo;
err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
"max-ring-page-order", "%u", _page_order);
@@ -1374,7 +1423,8 @@ static int talk_to_blkback(struct xenbus_device *dev,
}
for (i = 0; i < info->nr_rings; i++) {
- rinfo = >rinfo[i];
+ struct blkfront_ring_info *rinfo = >rinfo[i];
+
/* Create shared ring, alloc event channel. */
err = setup_blkring(dev, rinfo);
if (err)
@@ -1388,45 +1438,51 @@ again:
goto destroy_blkring;
}
- if (info->nr_rings == 1) {
- rinfo = >rinfo[0];
- if (info->nr_ring_pages == 1) {
- err = xenbus_printf(xbt, dev->nodename,
- "ring-ref", "%u",
rinfo->ring_ref[0]);
- if (err) {
-
[PATCH v4 05/10] xen/blkfront: negotiate number of queues/rings to be used with backend
The number of hardware queues for xen/blkfront is set by parameter
'max_queues'(default 4), while the max value xen/blkback supported is notified
through xenstore("multi-queue-max-queues").
The negotiated number is the smaller one and would be written back to xenstore
as "multi-queue-num-queues", blkback need to read this negotiated number.
Signed-off-by: Bob Liu
---
drivers/block/xen-blkfront.c | 166 +++
1 file changed, 120 insertions(+), 46 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 8cc5995..23096d7 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -98,6 +98,10 @@ static unsigned int xen_blkif_max_segments = 32;
module_param_named(max, xen_blkif_max_segments, int, S_IRUGO);
MODULE_PARM_DESC(max, "Maximum amount of segments in indirect requests
(default is 32)");
+static unsigned int xen_blkif_max_queues = 4;
+module_param_named(max_queues, xen_blkif_max_queues, uint, S_IRUGO);
+MODULE_PARM_DESC(max_queues, "Maximum number of hardware queues/rings used per
virtual disk");
+
/*
* Maximum order of pages to be used for the shared ring between front and
* backend, 4KB page granularity is used.
@@ -113,6 +117,7 @@ MODULE_PARM_DESC(max_ring_page_order, "Maximum order of
pages to be used for the
* characters are enough. Define to 20 to keep consist with backend.
*/
#define RINGREF_NAME_LEN (20)
+#define QUEUE_NAME_LEN (12)
/*
* Per-ring info.
@@ -695,7 +700,7 @@ static int xlvbd_init_blk_queue(struct gendisk *gd, u16
sector_size,
memset(>tag_set, 0, sizeof(info->tag_set));
info->tag_set.ops = _mq_ops;
- info->tag_set.nr_hw_queues = 1;
+ info->tag_set.nr_hw_queues = info->nr_rings;
info->tag_set.queue_depth = BLK_RING_SIZE(info);
info->tag_set.numa_node = NUMA_NO_NODE;
info->tag_set.flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
@@ -1352,6 +1357,51 @@ fail:
return err;
}
+static int write_per_ring_nodes(struct xenbus_transaction xbt,
+ struct blkfront_ring_info *rinfo, const char
*dir)
+{
+ int err, i;
+ const char *message = NULL;
+ struct blkfront_info *info = rinfo->dev_info;
+
+ if (info->nr_ring_pages == 1) {
+ err = xenbus_printf(xbt, dir, "ring-ref", "%u",
rinfo->ring_ref[0]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ pr_info("%s: write ring-ref:%d\n", dir, rinfo->ring_ref[0]);
+ } else {
+ for (i = 0; i < info->nr_ring_pages; i++) {
+ char ring_ref_name[RINGREF_NAME_LEN];
+
+ snprintf(ring_ref_name, RINGREF_NAME_LEN, "ring-ref%u",
i);
+ err = xenbus_printf(xbt, dir, ring_ref_name,
+ "%u", rinfo->ring_ref[i]);
+ if (err) {
+ message = "writing ring-ref";
+ goto abort_transaction;
+ }
+ pr_info("%s: write ring-ref:%d\n", dir,
rinfo->ring_ref[i]);
+ }
+ }
+
+ err = xenbus_printf(xbt, dir, "event-channel", "%u", rinfo->evtchn);
+ if (err) {
+ message = "writing event-channel";
+ goto abort_transaction;
+ }
+ pr_info("%s: write event-channel:%d\n", dir, rinfo->evtchn);
+
+ return 0;
+
+abort_transaction:
+ xenbus_transaction_end(xbt, 1);
+ if (message)
+ xenbus_dev_fatal(info->xbdev, err, "%s", message);
+
+ return err;
+}
/* Common code used when first setting up, and when resuming. */
static int talk_to_blkback(struct xenbus_device *dev,
@@ -1362,7 +1412,6 @@ static int talk_to_blkback(struct xenbus_device *dev,
int err, i;
unsigned int max_page_order = 0;
unsigned int ring_page_order = 0;
- struct blkfront_ring_info *rinfo;
err = xenbus_scanf(XBT_NIL, info->xbdev->otherend,
"max-ring-page-order", "%u", _page_order);
@@ -1374,7 +1423,8 @@ static int talk_to_blkback(struct xenbus_device *dev,
}
for (i = 0; i < info->nr_rings; i++) {
- rinfo = >rinfo[i];
+ struct blkfront_ring_info *rinfo = >rinfo[i];
+
/* Create shared ring, alloc event channel. */
err = setup_blkring(dev, rinfo);
if (err)
@@ -1388,45 +1438,51 @@ again:
goto destroy_blkring;
}
- if (info->nr_rings == 1) {
- rinfo = >rinfo[0];
- if (info->nr_ring_pages == 1) {
- err = xenbus_printf(xbt, dev->nodename,
- "ring-ref", "%u",
rinfo->ring_ref[0]);
- if (err) {
-
