From: Robert Olsson <[EMAIL PROTECTED]>
Date: Sat, 8 Sep 2007 09:53:49 +0200
> Yes a correct observation. I've spotted this bug too and it caused by the
> policy change in the NAPI scheduling. Look at tx_cleaned.
>
> I suggest we revert this change for now.
The tx_cleaned logic change was not intentional, and
that's the bug that makes e1000 spin endlessly in NAPI.
The other part, the work_done < budget part, was intentional
so I'm going to keep it in there for now. I've checked
in the patch below to deal with this.
I suspect the check "work_done == 0" is some shamans dance
to get slightly better performance, but it's 1) wrong and
2) at best needs to be explained in a comment and fully
quantified.
>From e8cbb449155000eecc6e855ea71510fecfc7d5ee Mon Sep 17 00:00:00 2001
From: David S. Miller <[EMAIL PROTECTED](none)>
Date: Wed, 12 Sep 2007 16:50:32 +0200
Subject: [PATCH] [E1000]: Fix unintended NAPI breakout logic change.
The inversion of the !tx_cleaned test in e1000_clean()
was not intentional, we just wanted to change the
"work_done == 0" to "work_done < budget"
Noticed by Robert Olsson.
Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
---
drivers/net/e1000/e1000_main.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index 7b0bcdb..58bb758 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3944,7 +3944,7 @@ e1000_clean(struct napi_struct *napi, int budget)
&work_done, budget);
/* If no Tx and not enough Rx work done, exit the polling mode */
- if ((tx_cleaned && (work_done < budget)) ||
+ if ((!tx_cleaned && (work_done < budget)) ||
!netif_running(poll_dev)) {
quit_polling:
if (likely(adapter->itr_setting & 3))
--
1.5.2.4
-
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