Re: [Xen-devel] xen/pcifront: Use monotonic clock

[Abhilash Jindal <klock.android@xxxxxxxxx>]

Oops. Thank you.

On Sat, Aug 8, 2015 at 10:16 PM, Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> wrote:

On 08/08/2015 09:36 PM, Abhilash Jindal wrote:

Wall time obtained from do_gettimeofday is susceptible to sudden jumps due to user setting the time or due to NTP.

Monotonic time is constantly increasing time better suited for comparing two
timestamps.

See commit e1d5bbcdc7ca08d8731f5d780f0de342a768d96a (you probably will need to update your tree)

-boris

---
Âdrivers/pci/xen-pcifront.c |Â Â10 +++++-----
Â1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/xen-pcifront.c b/drivers/pci/xen-pcifront.c
index f7197a7..5ef3eb7 100644
--- a/drivers/pci/xen-pcifront.c
+++ b/drivers/pci/xen-pcifront.c
@@ -114,7 +114,7 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
evtchn_port_t port = pdev->evtchn;
unsigned irq = pdev->irq;
s64 ns, ns_timeout;
-struct timeval tv;
+struct timespec tv;
spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
@@ -131,8 +131,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
* (in the latter case we end up continually re-executing poll() with a
* timeout in the past). 1s difference gives plenty of slack for error.
*/
-do_gettimeofday(&tv);
-ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
+ktime_get_ts(&tv);
+ns_timeout = timespec_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
xen_clear_irq_pending(irq);
@@ -140,8 +140,8 @@ static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
(unsigned long *)&pdev->sh_info->flags)) {
xen_poll_irq_timeout(irq, jiffies + 3*HZ);
xen_clear_irq_pending(irq);
-do_gettimeofday(&tv);
-ns = timeval_to_ns(&tv);
+ktime_get_ts(&tv);
+ns = timespec_to_ns(&tv);
if (ns > ns_timeout) {
dev_err(&pdev->xdev->dev,
"pciback not responding!!!\n");
--
1.7.9.5

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel