Re: [PATCH] Kmod optimization

[tyler]

On Thu, Apr 13, 2006 at 11:50:14AM -0700, Greg KH wrote:
> On Thu, Apr 13, 2006 at 08:36:17PM +0200, tyler@xxxxxxxx wrote:
> > On Thu, Apr 13, 2006 at 11:24:01AM -0700, Greg KH wrote:
> > > On Thu, Apr 13, 2006 at 08:03:45PM +0200, tyler@xxxxxxxx wrote:
> > > > Hi,
> > > > 
> > > > the request_mod functions try to load automatically a module by running
> > > > a user mode process helper (modprobe).
> > > > 
> > > > The user process is launched even if the module is already loaded. I
> > > > think it would be better to test if the module is already loaded.
> > > 
> > > Does this cause a problem somehow?  request_mod is called _very_
> > > infrequently from a normal kernel these days, so I really don't think
> > > this is necessary.
> > 
> > Yes I agree it _should_ be very infrequently called but it _will_ be very
> > infrequently called just if the user space configuration is done properly.
> 
> What do you mean by this?  Almost all 2.6 distros use udev today, which
> prevents this code from ever getting called.  So odds are, you are
> optimising something that no one will ever use :)
Well perhaps I don't understand the mechanism :) But let's take an
example.
On all kernels (even recent), if the module smbfs is loaded, it's not
handled by udev and request_module could be called.

Let"s take another example to see to illustrate why I think
it depends on the user configuration :
module A depends on module B

if we have a script which do "insmod moduleA.ko ; insmod moduleB.ko",
there will be a call to request_module.

if the script is "insmod moduleB.ko ; insmod moduleA.ko", request_mode
is not called.

I know the first script is really idiot :)

This is what I was thinking about in my previous mail.

-- 
tyler
tyler@xxxxxxxx


	

	
		
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