lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 07 Jun 2007 17:31:43 -0700
From:	Sridhar Samudrala <sri@...ibm.com>
To:	David Miller <davem@...emloft.net>
Cc:	hadi@...erus.ca, auke-jan.h.kok@...el.com, jeff@...zik.org,
	kaber@...sh.net, peter.p.waskiewicz.jr@...el.com,
	netdev@...r.kernel.org, jesse.brandeburg@...el.com
Subject: Re: [PATCH] NET: Multiqueue network device support.

On Thu, 2007-06-07 at 16:00 -0700, David Miller wrote:
> From: jamal <hadi@...erus.ca>
> Date: Thu, 07 Jun 2007 18:54:08 -0400
> 
> > On Thu, 2007-07-06 at 15:44 -0700, David Miller wrote:
> > > From: jamal <hadi@...erus.ca>
> > > Date: Thu, 07 Jun 2007 17:57:25 -0400
> > > 
> > > > I empathize but take a closer look; seems mostly useless.
> > > 
> > > I thought E1000 still uses LLTX, and if so then multiple cpus can most
> > > definitely get into the ->hard_start_xmit() in parallel.
> > 
> > AFAICS, only one CPU can dequeue from the qdisc i.e s/he who holds
> > __LINK_STATE_QDISC_RUNNING is the only one who can call qdisc_restart
> > and only s/he can enter ->hard_start_xmit().
> > 
> > Am i missing something?
> 
> That's right we fixed that the other week.

If the QDISC_RUNNING flag guarantees that only one CPU can call
dev->hard_start_xmit(), then why do we need to hold netif_tx_lock
for non-LLTX drivers?

Thanks
Sridhar

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

Powered by blists - more mailing lists