On Thu, Aug 29, 2024 at 03:48:05PM +0200, Eric Dumazet wrote:

On Thu, Aug 29, 2024 at 3:13 PM Joe Damato [off-list ref] wrote:

quoted

Allow per-NAPI gro_flush_timeout setting.

The existing sysfs parameter is respected; writes to sysfs will write to
all NAPI structs for the device and the net_device gro_flush_timeout
field.  Reads from sysfs will read from the net_device field.

The ability to set gro_flush_timeout on specific NAPI instances will be
added in a later commit, via netdev-genl.

Signed-off-by: Joe Damato <redacted>
Reviewed-by: Martin Karsten <redacted>
Tested-by: Martin Karsten <redacted>
---
 include/linux/netdevice.h | 26 ++++++++++++++++++++++++++
 net/core/dev.c            | 32 ++++++++++++++++++++++++++++----
 net/core/net-sysfs.c      |  2 +-
 3 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 7d53380da4c0..d00024d9f857 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h

@@ -372,6 +372,7 @@ struct napi_struct {
        int                     rx_count; /* length of rx_list */
        unsigned int            napi_id;
        int                     defer_hard_irqs;
+       unsigned long           gro_flush_timeout;
        struct hrtimer          timer;
        struct task_struct      *thread;
        /* control-path-only fields follow */

@@ -557,6 +558,31 @@ void napi_set_defer_hard_irqs(struct napi_struct *n, int defer);
  */
 void netdev_set_defer_hard_irqs(struct net_device *netdev, int defer);

Same remark :  dev->gro_flush_timeout is no longer read in the fast path.

Please move gro_flush_timeout out of net_device_read_txrx and update
Documentation/networking/net_cachelines/net_device.rst

Is there some tooling I should use to generate this file?

I am asking because it seems like the file is missing two fields in
net_device at the end of the struct:

struct hlist_head          page_pools;
struct dim_irq_moder *     irq_moder;

Both of which seem to have been added just before and long after
(respectively) commit 14006f1d8fa2 ("Documentations: Analyze heavily
used Networking related structs").

If this is a bug, I can submit one patch (with two fixes tags) which
adds both fields to the file?

- Joe