netdev.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Andy Gospodarek <andy@greyhouse.net>
To: netdev@vger.kernel.org, bruce.w.allan@intel.com,
	jeffrey.t.kirsher@intel.com, jesse.brandeburg@intel.com,
	alexander.h.duyck@intel.com
Cc: stable@kernel.org
Subject: [PATCH] e1000e: stop unnecessary polling when using msi-x
Date: Thu, 18 Jun 2009 17:57:37 -0400	[thread overview]
Message-ID: <20090618215737.GF8515@gospo.rdu.redhat.com> (raw)


The last hunk of this commit:

    commit 12d04a3c12b420f23398b4d650127642469a60a6
    Author: Alexander Duyck <alexander.h.duyck@intel.com>
    Date:   Wed Mar 25 22:05:03 2009 +0000

        e1000e: commonize tx cleanup routine to match e1000 & igb

changed the logic for determining if we should call napi_complete or
not at then end of a napi poll.

If the NIC is using MSI-X with no work to do in ->poll, net_rx_action
can just spin indefinitely on older kernels and for 2 jiffies on newer
kernels since napi_complete is never called and budget isn't
decremented.

Discovered and verified while testing driver backport to an older
kernel.

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>

---

 netdev.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 677f604..679885a 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -1997,7 +1997,7 @@ static int e1000_clean(struct napi_struct *napi, int budget)
 	struct e1000_adapter *adapter = container_of(napi, struct e1000_adapter, napi);
 	struct e1000_hw *hw = &adapter->hw;
 	struct net_device *poll_dev = adapter->netdev;
-	int tx_cleaned = 0, work_done = 0;
+	int tx_cleaned = 1, work_done = 0;
 
 	adapter = netdev_priv(poll_dev);



             reply	other threads:[~2009-06-18 21:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-06-18 21:57 Andy Gospodarek [this message]
2009-06-18 22:06 ` [PATCH] e1000e: stop unnecessary polling when using msi-x Alexander Duyck
2009-06-19  7:24   ` David Miller
2009-06-19 15:06     ` Andy Gospodarek
2009-06-22  8:52       ` David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20090618215737.GF8515@gospo.rdu.redhat.com \
    --to=andy@greyhouse.net \
    --cc=alexander.h.duyck@intel.com \
    --cc=bruce.w.allan@intel.com \
    --cc=jeffrey.t.kirsher@intel.com \
    --cc=jesse.brandeburg@intel.com \
    --cc=netdev@vger.kernel.org \
    --cc=stable@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).