4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eric Dumazet <eduma...@google.com>
[ Upstream commit 47d3a07528ecbbccf53bc4390d70b4e3d1c04fcf ]
The cited commit makes a great job of finding optimal shift/multiplier
values assuming a 10 seconds wrap around, but forgot to change the
overflow_period computation.
It overflows in cyclecounter_cyc2ns(), and the final result is 804 ms,
which is silly.
Lets simply use 5 seconds, no need to recompute this, given how it is
supposed to work.
Later, we will use a timer instead of a work queue, since the new RX
allocation schem will no longer need mlx4_en_recover_from_oom() and the
service_task firing every 250 ms.
Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according
to HW frequency")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Tariq Toukan <tar...@mellanox.com>
Cc: Eugenia Emantayev <euge...@mellanox.com>
Reviewed-by: Tariq Toukan <tar...@mellanox.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Sasha Levin <alexander.le...@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/net/ethernet/mellanox/mlx4/en_clock.c | 18 ++++++++----------
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 -
2 files changed, 8 insertions(+), 11 deletions(-)
--- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c
@@ -88,10 +88,17 @@ void mlx4_en_remove_timestamp(struct mlx
}
}
+#define MLX4_EN_WRAP_AROUND_SEC 10UL
+/* By scheduling the overflow check every 5 seconds, we have a reasonably
+ * good chance we wont miss a wrap around.
+ * TOTO: Use a timer instead of a work queue to increase the guarantee.
+ */
+#define MLX4_EN_OVERFLOW_PERIOD (MLX4_EN_WRAP_AROUND_SEC * HZ / 2)
+
void mlx4_en_ptp_overflow_check(struct mlx4_en_dev *mdev)
{
bool timeout = time_is_before_jiffies(mdev->last_overflow_check +
- mdev->overflow_period);
+ MLX4_EN_OVERFLOW_PERIOD);
unsigned long flags;
if (timeout) {
@@ -236,7 +243,6 @@ static const struct ptp_clock_info mlx4_
.enable = mlx4_en_phc_enable,
};
-#define MLX4_EN_WRAP_AROUND_SEC 10ULL
/* This function calculates the max shift that enables the user range
* of MLX4_EN_WRAP_AROUND_SEC values in the cycles register.
@@ -261,7 +267,6 @@ void mlx4_en_init_timestamp(struct mlx4_
{
struct mlx4_dev *dev = mdev->dev;
unsigned long flags;
- u64 ns, zero = 0;
/* mlx4_en_init_timestamp is called for each netdev.
* mdev->ptp_clock is common for all ports, skip initialization if
@@ -285,13 +290,6 @@ void mlx4_en_init_timestamp(struct mlx4_
ktime_to_ns(ktime_get_real()));
write_unlock_irqrestore(&mdev->clock_lock, flags);
- /* Calculate period in seconds to call the overflow watchdog - to make
- * sure counter is checked at least once every wrap around.
- */
- ns = cyclecounter_cyc2ns(&mdev->cycles, mdev->cycles.mask, zero, &zero);
- do_div(ns, NSEC_PER_SEC / 2 / HZ);
- mdev->overflow_period = ns;
-
/* Configure the PHC */
mdev->ptp_clock_info = mlx4_en_ptp_clock_info;
snprintf(mdev->ptp_clock_info.name, 16, "mlx4 ptp");
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -419,7 +419,6 @@ struct mlx4_en_dev {
struct cyclecounter cycles;
struct timecounter clock;
unsigned long last_overflow_check;
- unsigned long overflow_period;
struct ptp_clock *ptp_clock;
struct ptp_clock_info ptp_clock_info;
struct notifier_block nb;
