* [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout
@ 2013-10-28 12:07 Wei Liu
0 siblings, 0 replies; 6+ messages in thread
From: Wei Liu @ 2013-10-28 12:07 UTC (permalink / raw)
To: xen-devel, netdev
Cc: Wei Liu, Ian Campbell, annie.li, david.vrabel, jbeulich, Jason Luan
time_after_eq() only works if the delta is < MAX_ULONG/2.
For a 32bit Dom0, if netfront sends packets at a very low rate, the time
between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
and the test for timer_after_eq() will be incorrect. Credit will not be
replenished and the guest may become unable to send packets (e.g., if
prior to the long gap, all credit was exhausted).
Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jason Luan <jianhai.luan@oracle.com>
---
drivers/net/xen-netback/common.h | 1 +
drivers/net/xen-netback/interface.c | 3 +--
drivers/net/xen-netback/netback.c | 10 +++++-----
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 5715318..400fea1 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -163,6 +163,7 @@ struct xenvif {
unsigned long credit_usec;
unsigned long remaining_credit;
struct timer_list credit_timeout;
+ u64 credit_window_start;
/* Statistics */
unsigned long rx_gso_checksum_fixup;
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 01bb854..459935a 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -312,8 +312,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
vif->credit_bytes = vif->remaining_credit = ~0UL;
vif->credit_usec = 0UL;
init_timer(&vif->credit_timeout);
- /* Initialize 'expires' now: it's used to track the credit window. */
- vif->credit_timeout.expires = jiffies;
+ vif->credit_window_start = get_jiffies_64();
dev->netdev_ops = &xenvif_netdev_ops;
dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index f3e591c..900da4b 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1185,9 +1185,8 @@ out:
static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
{
- unsigned long now = jiffies;
- unsigned long next_credit =
- vif->credit_timeout.expires +
+ u64 now = get_jiffies_64();
+ u64 next_credit = vif->credit_window_start +
msecs_to_jiffies(vif->credit_usec / 1000);
/* Timer could already be pending in rare cases. */
@@ -1195,8 +1194,8 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
return true;
/* Passed the point where we can replenish credit? */
- if (time_after_eq(now, next_credit)) {
- vif->credit_timeout.expires = now;
+ if (time_after_eq64(now, next_credit)) {
+ vif->credit_window_start = now;
tx_add_credit(vif);
}
@@ -1208,6 +1207,7 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
tx_credit_callback;
mod_timer(&vif->credit_timeout,
next_credit);
+ vif->credit_window_start = next_credit;
return true;
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout
2013-10-28 12:07 Wei Liu
` (2 preceding siblings ...)
2013-10-29 4:25 ` David Miller
@ 2013-10-29 4:25 ` David Miller
3 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2013-10-29 4:25 UTC (permalink / raw)
To: wei.liu2
Cc: xen-devel, netdev, david.vrabel, jbeulich, annie.li,
ian.campbell, jianhai.luan
From: Wei Liu <wei.liu2@citrix.com>
Date: Mon, 28 Oct 2013 12:07:57 +0000
> time_after_eq() only works if the delta is < MAX_ULONG/2.
>
> For a 32bit Dom0, if netfront sends packets at a very low rate, the time
> between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
> and the test for timer_after_eq() will be incorrect. Credit will not be
> replenished and the guest may become unable to send packets (e.g., if
> prior to the long gap, all credit was exhausted).
>
> Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
>
> Suggested-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout
2013-10-28 12:07 Wei Liu
2013-10-29 2:39 ` annie li
2013-10-29 2:39 ` annie li
@ 2013-10-29 4:25 ` David Miller
2013-10-29 4:25 ` David Miller
3 siblings, 0 replies; 6+ messages in thread
From: David Miller @ 2013-10-29 4:25 UTC (permalink / raw)
To: wei.liu2
Cc: ian.campbell, netdev, xen-devel, annie.li, david.vrabel,
jbeulich, jianhai.luan
From: Wei Liu <wei.liu2@citrix.com>
Date: Mon, 28 Oct 2013 12:07:57 +0000
> time_after_eq() only works if the delta is < MAX_ULONG/2.
>
> For a 32bit Dom0, if netfront sends packets at a very low rate, the time
> between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
> and the test for timer_after_eq() will be incorrect. Credit will not be
> replenished and the guest may become unable to send packets (e.g., if
> prior to the long gap, all credit was exhausted).
>
> Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
>
> Suggested-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout
2013-10-28 12:07 Wei Liu
@ 2013-10-29 2:39 ` annie li
2013-10-29 2:39 ` annie li
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: annie li @ 2013-10-29 2:39 UTC (permalink / raw)
To: Wei Liu
Cc: xen-devel, netdev, david.vrabel, jbeulich, Ian Campbell, Jason Luan
On 2013-10-28 20:07, Wei Liu wrote:
> time_after_eq() only works if the delta is < MAX_ULONG/2.
>
> For a 32bit Dom0, if netfront sends packets at a very low rate, the time
> between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
> and the test for timer_after_eq() will be incorrect. Credit will not be
> replenished and the guest may become unable to send packets (e.g., if
> prior to the long gap, all credit was exhausted).
>
> Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
>
> Suggested-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Jason Luan <jianhai.luan@oracle.com>
> ---
> drivers/net/xen-netback/common.h | 1 +
> drivers/net/xen-netback/interface.c | 3 +--
> drivers/net/xen-netback/netback.c | 10 +++++-----
> 3 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
> index 5715318..400fea1 100644
> --- a/drivers/net/xen-netback/common.h
> +++ b/drivers/net/xen-netback/common.h
> @@ -163,6 +163,7 @@ struct xenvif {
> unsigned long credit_usec;
> unsigned long remaining_credit;
> struct timer_list credit_timeout;
> + u64 credit_window_start;
>
> /* Statistics */
> unsigned long rx_gso_checksum_fixup;
> diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
> index 01bb854..459935a 100644
> --- a/drivers/net/xen-netback/interface.c
> +++ b/drivers/net/xen-netback/interface.c
> @@ -312,8 +312,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
> vif->credit_bytes = vif->remaining_credit = ~0UL;
> vif->credit_usec = 0UL;
> init_timer(&vif->credit_timeout);
> - /* Initialize 'expires' now: it's used to track the credit window. */
> - vif->credit_timeout.expires = jiffies;
> + vif->credit_window_start = get_jiffies_64();
>
> dev->netdev_ops = &xenvif_netdev_ops;
> dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index f3e591c..900da4b 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -1185,9 +1185,8 @@ out:
>
> static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
> {
> - unsigned long now = jiffies;
> - unsigned long next_credit =
> - vif->credit_timeout.expires +
> + u64 now = get_jiffies_64();
> + u64 next_credit = vif->credit_window_start +
> msecs_to_jiffies(vif->credit_usec / 1000);
>
> /* Timer could already be pending in rare cases. */
> @@ -1195,8 +1194,8 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
> return true;
>
> /* Passed the point where we can replenish credit? */
> - if (time_after_eq(now, next_credit)) {
> - vif->credit_timeout.expires = now;
> + if (time_after_eq64(now, next_credit)) {
> + vif->credit_window_start = now;
> tx_add_credit(vif);
> }
>
> @@ -1208,6 +1207,7 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
> tx_credit_callback;
> mod_timer(&vif->credit_timeout,
> next_credit);
> + vif->credit_window_start = next_credit;
>
> return true;
> }
This patch looks good, thanks Wei.
Thanks
Annie
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout
2013-10-28 12:07 Wei Liu
2013-10-29 2:39 ` annie li
@ 2013-10-29 2:39 ` annie li
2013-10-29 4:25 ` David Miller
2013-10-29 4:25 ` David Miller
3 siblings, 0 replies; 6+ messages in thread
From: annie li @ 2013-10-29 2:39 UTC (permalink / raw)
To: Wei Liu
Cc: Ian Campbell, netdev, xen-devel, david.vrabel, jbeulich, Jason Luan
On 2013-10-28 20:07, Wei Liu wrote:
> time_after_eq() only works if the delta is < MAX_ULONG/2.
>
> For a 32bit Dom0, if netfront sends packets at a very low rate, the time
> between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
> and the test for timer_after_eq() will be incorrect. Credit will not be
> replenished and the guest may become unable to send packets (e.g., if
> prior to the long gap, all credit was exhausted).
>
> Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
>
> Suggested-by: Jan Beulich <jbeulich@suse.com>
> Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> Reviewed-by: David Vrabel <david.vrabel@citrix.com>
> Cc: Ian Campbell <ian.campbell@citrix.com>
> Cc: Jason Luan <jianhai.luan@oracle.com>
> ---
> drivers/net/xen-netback/common.h | 1 +
> drivers/net/xen-netback/interface.c | 3 +--
> drivers/net/xen-netback/netback.c | 10 +++++-----
> 3 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
> index 5715318..400fea1 100644
> --- a/drivers/net/xen-netback/common.h
> +++ b/drivers/net/xen-netback/common.h
> @@ -163,6 +163,7 @@ struct xenvif {
> unsigned long credit_usec;
> unsigned long remaining_credit;
> struct timer_list credit_timeout;
> + u64 credit_window_start;
>
> /* Statistics */
> unsigned long rx_gso_checksum_fixup;
> diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
> index 01bb854..459935a 100644
> --- a/drivers/net/xen-netback/interface.c
> +++ b/drivers/net/xen-netback/interface.c
> @@ -312,8 +312,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
> vif->credit_bytes = vif->remaining_credit = ~0UL;
> vif->credit_usec = 0UL;
> init_timer(&vif->credit_timeout);
> - /* Initialize 'expires' now: it's used to track the credit window. */
> - vif->credit_timeout.expires = jiffies;
> + vif->credit_window_start = get_jiffies_64();
>
> dev->netdev_ops = &xenvif_netdev_ops;
> dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
> index f3e591c..900da4b 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -1185,9 +1185,8 @@ out:
>
> static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
> {
> - unsigned long now = jiffies;
> - unsigned long next_credit =
> - vif->credit_timeout.expires +
> + u64 now = get_jiffies_64();
> + u64 next_credit = vif->credit_window_start +
> msecs_to_jiffies(vif->credit_usec / 1000);
>
> /* Timer could already be pending in rare cases. */
> @@ -1195,8 +1194,8 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
> return true;
>
> /* Passed the point where we can replenish credit? */
> - if (time_after_eq(now, next_credit)) {
> - vif->credit_timeout.expires = now;
> + if (time_after_eq64(now, next_credit)) {
> + vif->credit_window_start = now;
> tx_add_credit(vif);
> }
>
> @@ -1208,6 +1207,7 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
> tx_credit_callback;
> mod_timer(&vif->credit_timeout,
> next_credit);
> + vif->credit_window_start = next_credit;
>
> return true;
> }
This patch looks good, thanks Wei.
Thanks
Annie
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout
@ 2013-10-28 12:07 Wei Liu
2013-10-29 2:39 ` annie li
` (3 more replies)
0 siblings, 4 replies; 6+ messages in thread
From: Wei Liu @ 2013-10-28 12:07 UTC (permalink / raw)
To: xen-devel, netdev
Cc: david.vrabel, jbeulich, annie.li, Wei Liu, Ian Campbell, Jason Luan
time_after_eq() only works if the delta is < MAX_ULONG/2.
For a 32bit Dom0, if netfront sends packets at a very low rate, the time
between subsequent calls to tx_credit_exceeded() may exceed MAX_ULONG/2
and the test for timer_after_eq() will be incorrect. Credit will not be
replenished and the guest may become unable to send packets (e.g., if
prior to the long gap, all credit was exhausted).
Use jiffies_64 variant to mitigate this problem for 32bit Dom0.
Suggested-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Jason Luan <jianhai.luan@oracle.com>
---
drivers/net/xen-netback/common.h | 1 +
drivers/net/xen-netback/interface.c | 3 +--
drivers/net/xen-netback/netback.c | 10 +++++-----
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 5715318..400fea1 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -163,6 +163,7 @@ struct xenvif {
unsigned long credit_usec;
unsigned long remaining_credit;
struct timer_list credit_timeout;
+ u64 credit_window_start;
/* Statistics */
unsigned long rx_gso_checksum_fixup;
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index 01bb854..459935a 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -312,8 +312,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
vif->credit_bytes = vif->remaining_credit = ~0UL;
vif->credit_usec = 0UL;
init_timer(&vif->credit_timeout);
- /* Initialize 'expires' now: it's used to track the credit window. */
- vif->credit_timeout.expires = jiffies;
+ vif->credit_window_start = get_jiffies_64();
dev->netdev_ops = &xenvif_netdev_ops;
dev->hw_features = NETIF_F_SG | NETIF_F_IP_CSUM | NETIF_F_TSO;
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index f3e591c..900da4b 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -1185,9 +1185,8 @@ out:
static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
{
- unsigned long now = jiffies;
- unsigned long next_credit =
- vif->credit_timeout.expires +
+ u64 now = get_jiffies_64();
+ u64 next_credit = vif->credit_window_start +
msecs_to_jiffies(vif->credit_usec / 1000);
/* Timer could already be pending in rare cases. */
@@ -1195,8 +1194,8 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
return true;
/* Passed the point where we can replenish credit? */
- if (time_after_eq(now, next_credit)) {
- vif->credit_timeout.expires = now;
+ if (time_after_eq64(now, next_credit)) {
+ vif->credit_window_start = now;
tx_add_credit(vif);
}
@@ -1208,6 +1207,7 @@ static bool tx_credit_exceeded(struct xenvif *vif, unsigned size)
tx_credit_callback;
mod_timer(&vif->credit_timeout,
next_credit);
+ vif->credit_window_start = next_credit;
return true;
}
--
1.7.10.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-10-29 4:25 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-10-28 12:07 [PATCH net V3] xen-netback: use jiffies_64 value to calculate credit timeout Wei Liu
2013-10-28 12:07 Wei Liu
2013-10-29 2:39 ` annie li
2013-10-29 2:39 ` annie li
2013-10-29 4:25 ` David Miller
2013-10-29 4:25 ` David Miller
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