[6.1.y,cip,v2,5/9] net: add netdev_sw_irq_coalesce_default_on()

Commit Message

Paul Barker Aug. 27, 2024, 9:06 p.m. UTC

From: Heiner Kallweit <[e-mail]>

commit d93607082e982223cf92750f2d9039ff365b9d24 upstream.

Add a helper for drivers wanting to set SW IRQ coalescing
by default. The related sysfs attributes can be used to
override the default values.

Follow Jakub's suggestion and put this functionality into
net core so that drivers wanting to use software interrupt
coalescing per default don't have to open-code it.

Note that this function needs to be called before the
netdevice is registered.

Suggested-by: Jakub Kicinski <[e-mail]>
Signed-off-by: Heiner Kallweit <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>
Reviewed-by: Pavel Machek <[e-mail]>
Signed-off-by: Paul Barker <[e-mail]>
---
 include/linux/netdevice.h |  1 +
 net/core/dev.c            | 16 ++++++++++++++++
 2 files changed, 17 insertions(+)

Patch

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 0373e0935990..ca90dfb71299 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -78,6 +78,7 @@  struct xdp_buff;
 void synchronize_net(void);
 void netdev_set_default_ethtool_ops(struct net_device *dev,
 				    const struct ethtool_ops *ops);
+void netdev_sw_irq_coalesce_default_on(struct net_device *dev);
 
 /* Backlog congestion levels */
 #define NET_RX_SUCCESS		0	/* keep 'em coming, baby */
diff --git a/net/core/dev.c b/net/core/dev.c
index 20d8b9195ef6..895082bd254b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10570,6 +10570,22 @@  void netdev_set_default_ethtool_ops(struct net_device *dev,
 }
 EXPORT_SYMBOL_GPL(netdev_set_default_ethtool_ops);
 
+/**
+ * netdev_sw_irq_coalesce_default_on() - enable SW IRQ coalescing by default
+ * @dev: netdev to enable the IRQ coalescing on
+ *
+ * Sets a conservative default for SW IRQ coalescing. Users can use
+ * sysfs attributes to override the default values.
+ */
+void netdev_sw_irq_coalesce_default_on(struct net_device *dev)
+{
+	WARN_ON(dev->reg_state == NETREG_REGISTERED);
+
+	dev->gro_flush_timeout = 20000;
+	dev->napi_defer_hard_irqs = 1;
+}
+EXPORT_SYMBOL_GPL(netdev_sw_irq_coalesce_default_on);
+
 void netdev_freemem(struct net_device *dev)
 {
 	char *addr = (char *)dev - dev->padded;