From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Subject: Re: [RFC v2 3/6] kthread: warn on kill signal if not OOM
Date: Fri, 5 Sep 2014 11:10:03 -0700
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Cc: "Luis R. Rodriguez" <mcgrof@do-not-panic.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Wu Zhangjin <falcon@meizu.com>, Takashi Iwai <tiwai@suse.de>,
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	Andrew Morton <akpm@linux-foundation.org>,
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	Joseph Salisbury <joseph.salisbury@canonical.com>,
	Benjamin Poirier <bpoirier@suse.de>,
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	Kay Sievers <kay@vrfy.org>,
	One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>,
	Tim Gardner <tim.gardner@canonical.com>,
	Pierre Fersing <pierre-fersing@pierref.org>,
	Nagalakshmi Nandigama <nagalakshmi.nandigama@avagotech.com>,
	Praveen Krishnamoorthy <praveen.krishnamoorthy@avagotech.com>,
	Sreekanth Reddy <sreekanth.reddy@avagotech.com>,
	Abhijit
To: Tejun Heo <tj@kernel.org>
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On Sat, Sep 06, 2014 at 02:49:25AM +0900, Tejun Heo wrote:
> Hello,
> 
> On Fri, Sep 05, 2014 at 09:44:05AM -0700, Dmitry Torokhov wrote:
> > Which problem are we talking about here though? It does solve the slow device
> > stalling the rest if the kernel booting (non-module case) for me.
> 
> The other one.  The one with timeout.  Neither cxgb4 or pata_marvell
> has slow probing stalling boot problem.
> 
> > I also reject the notion that anyone should be relying on drivers to be fully
> > bound on module loading. It is not nineties anymore. We have hot pluggable
> > buses, deferred probing, and even for not hot-pluggable ones the module
> > providing the device itself might not be yet loaded. Any scripts that expect to
> > find device 100% ready after module loading are simply broken.
> 
> We've been treating loading + probing as a single operation when
> loading drivers and the assumption has always been that the existing
> devices at the time of loading finished probing by the time insmod
> finishes.  We now need to split loading and probing and wait for each
> of them differently.  The *only* thing we can do is somehow making the
> issuer specify that it's gonna wait for probing separately.  I'm not
> sure this can even be up for discussion.  We're talking about a major
> userland visible behavior change.

I do not agree that it is actually user-visible change: generally speaking you
do not really know if device is there or not. They come and go. Like I said,
consider all permutations, with hot-pluggable buses, deferred probing, etc,
etc.

Thanks.

-- 
Dmitry