Re: [PATCH, v2] PCI: create function symlinks in/sys/bus/pci/slots/N/

From: Alex Chiang
Date: Sat Aug 23 2008 - 16:04:58 EST


* Greg KH <greg@xxxxxxxxx>:
> On Fri, Aug 22, 2008 at 01:53:58PM -0600, Alex Chiang wrote:
> >
> > Does anyone have numbers for how much it costs to create a new
> > symlink? I could try and figure this out but it will take a few
> > days (busy with other stuff).
>
> Almost nothing.
>
> sysfs creates these things on the fly as they are accessed, and if
> memory pressure on the machine happens, they are freed up properly and
> then created again if a user asks to see them in the tree.
>
> So don't worry about memory issues when adding new files or symlinks in
> sysfs, it just isn't a problem (we handle 20000 disks easily on low
> memory 31bit s390 systems.)

Great, thanks for the explanation. I've heard the "memory
overhead" argument before for not wanting to create other sysfs
files/links, so this will be good to debunk that bogeyman if it
pops up again in the future.

Did you get a chance to take a look at the documentation I wrote
for these new symlinks? [I also went and documented the existing
slots/ directory as well...]

Was it what you had in mind?

Thanks.

/ac

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