From: Konstantin Khlebnikov khlebnikov@yandex-team.ru
[ Upstream commit a4837980fd9fa4c70a821d11831698901baef56b ]
For HZ < 1000 timeout 2000us rounds up to 1 jiffy but expires randomly because next timer interrupt could come shortly after starting softirq.
For commonly used CONFIG_HZ=1000 nothing changes.
Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") Reported-by: Dmitry Yakunin zeil@yandex-team.ru Signed-off-by: Konstantin Khlebnikov khlebnikov@yandex-team.ru Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/core/dev.c +++ b/net/core/dev.c @@ -4090,7 +4090,8 @@ EXPORT_SYMBOL(netdev_max_backlog);
int netdev_tstamp_prequeue __read_mostly = 1; int netdev_budget __read_mostly = 300; -unsigned int __read_mostly netdev_budget_usecs = 2000; +/* Must be at least 2 jiffes to guarantee 1 jiffy timeout */ +unsigned int __read_mostly netdev_budget_usecs = 2 * USEC_PER_SEC / HZ; int weight_p __read_mostly = 64; /* old backlog weight */ int dev_weight_rx_bias __read_mostly = 1; /* bias for backlog weight */ int dev_weight_tx_bias __read_mostly = 1; /* bias for output_queue quota */