linux-kernel - Re: Re: [PATCH 2/2] 2.6.19-rc1-mm1 pktcdvd: bio write congestion

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Message-Id: <E1GZO8u-0006bn-VJ@www14.emo.freenet-rz.de>
Date:	Mon, 16 Oct 2006 10:48:16 +0200
From:	balagi@...tmail.de
To:	"Jens Axboe" <jens.axboe@...cle.com>,
	"Peter Osterlund" <petero2@...ia.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: Re: [PATCH 2/2] 2.6.19-rc1-mm1 pktcdvd: bio write congestion

Hello,

the congestion control will work with both code changes, but i am
not sure, if using clear_queue_congested() and blk_congestion_wait()
is the right thing to use here: it works on global level. Any other
thread/driver/etc. can do a clear_queue_congested() and wake
up anyone waiting on this global write or read wait queue, resulting to
unneeded task switches.
The driver local solution (own waitqueue) would prevent this.....

-Thomas Maier


----- original Nachricht --------

Betreff: Re: [PATCH 2/2] 2.6.19-rc1-mm1 pktcdvd: bio write congestion
Gesendet: So 15 Okt 2006 20:16:31 CEST
Von: "Jens Axboe"<jens.axboe@...cle.com>

> On Sat, Oct 14 2006, Peter Osterlund wrote:
> > "Thomas Maier" <balagi@...tmail.de> writes:
> > 
> > > Hello,
> > > 
> > > this adds a bio write queue congestion control
> > > to the pktcdvd driver with fixed on/off marks.
> > > It prevents that the driver consumes a unlimited
> > > amount of write requests.
> > 
> > Thanks, this looks good in principle, but I think it can be
> > implemented in a simpler way.
> > 
> > Jens, can I please ask your opinion. Would it make sense to export the
> > clear_queue_congested() and set_queue_congested() functions in
> > ll_rw_blk.c so that the pktcdvd driver can use them? Something like
> > this patch from a few years ago:
> > 
> >        
> http://marc.theaimsgroup.com/?l=linux-kernel&m=109378210610508&w=2
> 
> It definitely would. Did you test, and did it work well for you? I think
> it's the right approach.
> 
> -- 
> Jens Axboe
> 
> 

--- original Nachricht Ende ----









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