net: don't set sw irq coalescing defaults in case of PREEMPT_RT

If PREEMPT_RT is set, then assume that the user focuses on minimum
latency. Therefore don't set sw irq coalescing defaults.
This affects the defaults only, users can override these settings
via sysfs.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Link: https://lore.kernel.org/r/f9439c7f-c92c-4c2c-703e-110f96d841b7@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/core/dev.c b/net/core/dev.c
index 3393c2f3dbe88a8db215c5b613c922dbafb2913e..99d99b247bc97605684f566baf48147e35e9af32 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10571,8 +10571,10 @@ 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;
+       if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
+               dev->gro_flush_timeout = 20000;
+               dev->napi_defer_hard_irqs = 1;
+       }
 }
 EXPORT_SYMBOL_GPL(netdev_sw_irq_coalesce_default_on);