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Re: [openib-general] Re: LLTX and netif_stop_queue

To: Jeff Garzik <jgarzik@xxxxxxxxx>
Subject: Re: [openib-general] Re: LLTX and netif_stop_queue
From: Stephen Hemminger <shemminger@xxxxxxxx>
Date: Wed, 19 Jan 2005 16:46:14 -0800
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>, hadi@xxxxxxxxxx, iod00d@xxxxxx, eric.lemoine@xxxxxxxxx, roland@xxxxxxxxxxx, netdev@xxxxxxxxxxx, ak@xxxxxxx, openib-general@xxxxxxxxxx, kaber@xxxxxxxxx
In-reply-to: <41EEF52C.8000905@pobox.com>
Organization: Open Source Development Lab
References: <5cac192f0412230110628749e3@mail.gmail.com> <41CAF444.3000305@trash.net> <5cac192f04122408102129af43@mail.gmail.com> <1104240717.1100.66.camel@jzny.localdomain> <5cac192f0501021530672a908a@mail.gmail.com> <1104764660.1048.578.camel@jzny.localdomain> <52brc68q05.fsf@topspin.com> <5cac192f05010308414a25b548@mail.gmail.com> <527jmu8nbw.fsf@topspin.com> <5cac192f0501030907c755135@mail.gmail.com> <20050103171227.GD7370@esmail.cup.hp.com> <1104812294.1085.53.camel@jzny.localdomain> <20050119144711.3fdd3d93.davem@davemloft.net> <20050119151853.259de49a@dxpl.pdx.osdl.net> <20050119154132.68f0bb4f.davem@davemloft.net> <41EEF52C.8000905@pobox.com>
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On Wed, 19 Jan 2005 19:02:52 -0500
Jeff Garzik <jgarzik@xxxxxxxxx> wrote:

> David S. Miller wrote:
> > Usually we strive for BH disabling locks in order to decrease the
> > amount of hard IRQ disabling time in the kernel.  But here, as soon
> > as we call into ->hard_start_xmit(), the driver typically turns hard
> > IRQs off anyways.
> [...]
> > Also, changing dev->xmit_lock to be IRQ disabling is not %100 trivial.
> 
> 
> Agreed on both counts...

But in the end it would be safer than the current LLTX usage in drivers
which seems like it opening up problems.


-- 
Stephen Hemminger       <shemminger@xxxxxxxx>

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