[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [PATCH] net: Adjust softirq raising in __napi_schedule

Hash: SHA1

Am 26.10.2009 09:58 schrieb Johannes Berg:
> On Mon, 2009-10-26 at 07:54 +0000, Jarek Poplawski wrote:
>>> No, I wrote that I didn't know. I suppose now that I looked at it I do
>>> know, and only disabling preemption is required.
>> But netif_rx has preemption disabled most of the time (by hardirqs
>> disabling). So maybe disabling preemption isn't the main reason here
>> either?
> Not for netpoll though, which may or may not be relevant (if I were to
> venture a guess I'd say it isn't and it disables preemption to be able
> to do the softirq thing)
> However, I lost track now of why we're discussing this.

The starting point were several reports of the kernel message:

NOHZ: local_softirq_pending 08

Originally most if not all of them came from wireless networking,
but I muddied the waters by adding to the mix a case involving ISDN.
You stated that all the solutions proposed so far were wrong, so
we're naturally turning to you for guidance on what the right
solution might be.

> Basically it boils down to using netif_rx() when in (soft)irq, and
> netif_rx_ni() when in process context. That could just be an
> optimisation, but it's a very valid one.

Hmmm. That seems to contradict your earlier statement to me that
simply replacing a call to netif_rx() by one to netif_rx_ni()
when not in interrupt context isn't a valid solution either.
What am I missing?


- --
Tilman Schmidt                    E-Mail: tilman@xxxxxxx
Bonn, Germany
Diese Nachricht besteht zu 100% aus wiederverwerteten Bits.
Ungeöffnet mindestens haltbar bis: (siehe Rückseite)
Version: GnuPG v1.4.4 (MingW32)
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

To unsubscribe from this list: send the line "unsubscribe linux-ppp" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html

[Linux Audio Users]     [Hams]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Photo]     [Yosemite Photos]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linux Resources]     [Fedora Users]

Powered by Linux