log a message when we enter this situation:
1) we already allocated the max number of available grants from hypervisor
and
2) we still need more (but the request fails because of 1)).
Sometimes the lack of grants causes IO hangs in xen_blkfront devices.
Adding this log would help debuging.
Signed-off-by: Wengang Wang <[email protected]>
Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
Reviewed-by: Junxiao Bi <[email protected]>
---
drivers/xen/grant-table.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index d6786b8..2c6a911 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -42,6 +42,7 @@
#include <linux/delay.h>
#include <linux/hardirq.h>
#include <linux/workqueue.h>
+#include <linux/ratelimit.h>
#include <xen/xen.h>
#include <xen/interface/xen.h>
@@ -1072,8 +1073,14 @@ static int gnttab_expand(unsigned int req_entries)
cur = nr_grant_frames;
extra = ((req_entries + (grefs_per_grant_frame-1)) /
grefs_per_grant_frame);
- if (cur + extra > gnttab_max_grant_frames())
+ if (cur + extra > gnttab_max_grant_frames()) {
+ pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
+ " cur=%u extra=%u limit=%u"
+ " gnttab_free_count=%u req_entries=%u\n",
+ cur, extra, gnttab_max_grant_frames(),
+ gnttab_free_count, req_entries);
return -ENOSPC;
+ }
rc = gnttab_map(cur, cur + extra - 1);
if (rc == 0)
--
2.9.4
Hi,
Anyone can you please review this patch?
thanks,
wengang
On 07/07/2017 11:23 AM, Wengang Wang wrote:
> log a message when we enter this situation:
> 1) we already allocated the max number of available grants from hypervisor
> and
> 2) we still need more (but the request fails because of 1)).
>
> Sometimes the lack of grants causes IO hangs in xen_blkfront devices.
> Adding this log would help debuging.
>
> Signed-off-by: Wengang Wang <[email protected]>
> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
> Reviewed-by: Junxiao Bi <[email protected]>
> ---
> drivers/xen/grant-table.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
> index d6786b8..2c6a911 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -42,6 +42,7 @@
> #include <linux/delay.h>
> #include <linux/hardirq.h>
> #include <linux/workqueue.h>
> +#include <linux/ratelimit.h>
>
> #include <xen/xen.h>
> #include <xen/interface/xen.h>
> @@ -1072,8 +1073,14 @@ static int gnttab_expand(unsigned int req_entries)
> cur = nr_grant_frames;
> extra = ((req_entries + (grefs_per_grant_frame-1)) /
> grefs_per_grant_frame);
> - if (cur + extra > gnttab_max_grant_frames())
> + if (cur + extra > gnttab_max_grant_frames()) {
> + pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
> + " cur=%u extra=%u limit=%u"
> + " gnttab_free_count=%u req_entries=%u\n",
> + cur, extra, gnttab_max_grant_frames(),
> + gnttab_free_count, req_entries);
> return -ENOSPC;
> + }
>
> rc = gnttab_map(cur, cur + extra - 1);
> if (rc == 0)
On 07/13/2017 06:42 PM, Wengang wrote:
> Hi,
Hello,
> Anyone can you please review this patch?
Most of the developer community were at Xen Summit this week, so you may
expect some delay in review.
However, in general it is better to CC relevant maintainers of your code
to raise attention on your patch. I did it for you this time.
Cheers,
>
> thanks,
>
> wengang
>
>
> On 07/07/2017 11:23 AM, Wengang Wang wrote:
>> log a message when we enter this situation:
>> 1) we already allocated the max number of available grants from
>> hypervisor
>> and
>> 2) we still need more (but the request fails because of 1)).
>>
>> Sometimes the lack of grants causes IO hangs in xen_blkfront devices.
>> Adding this log would help debuging.
>>
>> Signed-off-by: Wengang Wang <[email protected]>
>> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
>> Reviewed-by: Junxiao Bi <[email protected]>
>> ---
>> drivers/xen/grant-table.c | 9 ++++++++-
>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
>> index d6786b8..2c6a911 100644
>> --- a/drivers/xen/grant-table.c
>> +++ b/drivers/xen/grant-table.c
>> @@ -42,6 +42,7 @@
>> #include <linux/delay.h>
>> #include <linux/hardirq.h>
>> #include <linux/workqueue.h>
>> +#include <linux/ratelimit.h>
>> #include <xen/xen.h>
>> #include <xen/interface/xen.h>
>> @@ -1072,8 +1073,14 @@ static int gnttab_expand(unsigned int req_entries)
>> cur = nr_grant_frames;
>> extra = ((req_entries + (grefs_per_grant_frame-1)) /
>> grefs_per_grant_frame);
>> - if (cur + extra > gnttab_max_grant_frames())
>> + if (cur + extra > gnttab_max_grant_frames()) {
>> + pr_warn_ratelimited("xen/grant-table: max_grant_frames reached"
>> + " cur=%u extra=%u limit=%u"
>> + " gnttab_free_count=%u req_entries=%u\n",
>> + cur, extra, gnttab_max_grant_frames(),
>> + gnttab_free_count, req_entries);
>> return -ENOSPC;
>> + }
>> rc = gnttab_map(cur, cur + extra - 1);
>> if (rc == 0)
>
>
> _______________________________________________
> Xen-devel mailing list
> [email protected]
> https://lists.xen.org/xen-devel
--
Julien Grall
On 07/07/17 20:23, Wengang Wang wrote:
> log a message when we enter this situation:
> 1) we already allocated the max number of available grants from hypervisor
> and
> 2) we still need more (but the request fails because of 1)).
>
> Sometimes the lack of grants causes IO hangs in xen_blkfront devices.
> Adding this log would help debuging.
>
> Signed-off-by: Wengang Wang <[email protected]>
> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
> Reviewed-by: Junxiao Bi <[email protected]>
Reviewed-by: Juergen Gross <[email protected]>
Thanks,
Juergen
On 07/07/17 20:23, Wengang Wang wrote:
> log a message when we enter this situation:
> 1) we already allocated the max number of available grants from hypervisor
> and
> 2) we still need more (but the request fails because of 1)).
>
> Sometimes the lack of grants causes IO hangs in xen_blkfront devices.
> Adding this log would help debuging.
>
> Signed-off-by: Wengang Wang <[email protected]>
> Reviewed-by: Konrad Rzeszutek Wilk <[email protected]>
> Reviewed-by: Junxiao Bi <[email protected]>
Committed to xen/tip for-linus-4.13
Thanks,
Juergen