On 25/5/2026 9:46 pm, Andrew Lunn wrote:

On Sun, May 24, 2026 at 11:16:53PM -0700, muhammad.nazim.amirul.nazle.asmade@altera.com wrote:

quoted

From: Nazim Amirul <redacted>

Currently hrtimer_start is called even if hrtimer is
active. This is unnecessary and expensive in some targets.
This patch avoids calling hrtimer_start unnecessarily.

Signed-off-by: Rohan G Thomas <redacted>
Signed-off-by: Nazim Amirul <redacted>
---
  drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 12 +++++++-----
  1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 3591755ea30b..35da51c26248 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

@@ -3341,12 +3341,14 @@ static void stmmac_tx_timer_arm(struct stmmac_priv *priv, u32 queue)
  	 * Try to cancel any timer if napi is scheduled, timer will be armed
  	 * again in the next scheduled napi.
  	 */
-	if (unlikely(!napi_is_scheduled(napi)))
-		hrtimer_start(&tx_q->txtimer,
-			      STMMAC_COAL_TIMER(tx_coal_timer),
-			      HRTIMER_MODE_REL);
-	else
+	if (unlikely(!napi_is_scheduled(napi))) {
+		if (unlikely(!(hrtimer_active(&tx_q->txtimer))))
+			hrtimer_start(&tx_q->txtimer,
+				      STMMAC_COAL_TIMER(tx_coal_timer),
+				      HRTIMER_MODE_REL);

Is there a race condition here? I've not thought about it enough to
know if there is/is not.

Also, does this change the meaning of tx_coal_timer?

I think the commit message needs expanding, to cover these issues. For
performance changes, it is also normal to include some performance
numbers, before/after, in the commit message.

     Andrew

---
pw-bot: cr

Hi Maxime, Andrew

Thanks for the quick review! I already send out v2 which applied all the 
comments.
https://lore.kernel.org/all/20260526051921.14540-1-muhammad.nazim.amirul.nazle.asmade@altera.com/ (local)