Re: [RFC 0/6] Backing Store for sysfs

[Greg KH <greg@kroah.com>]

On Tue, Oct 07, 2003 at 12:01:32AM +0530, Dipankar Sarma wrote:
> On Mon, Oct 06, 2003 at 11:09:07AM -0700, Greg KH wrote:
> > On Mon, Oct 06, 2003 at 11:31:19PM +0530, Dipankar Sarma wrote:
> > No.  My main point is that for every hotplug event (which is caused by a
> > kobject being created or destroyed), udev will run and look at the sysfs
> > entry for the kobject (by using libsysfs which reads in all of the
> > kobject information, including attributes).  This is a normal event, so
> > we have to care about what happens after running 'find' on the sysfs
> > tree as that is basically what will always happen.
> > 
> > Does that make more sense?  We can't just look at what happens with this
> > patch without actually accessing all of the sysfs tree, as that will be
> > the "normal" case.
> 
> That sounds odd. So, udev essentially results in a frequent and continuous
> "find /sys" ? That doesn't sound good. You are unnecessarily adding
> pressure on vfs (dcache specially). We will discuss this offline then
> and see what needs to be done.

No, not a 'find', we look up the kobject that was added, and its
attributes.  Doing a 'find' will emulate this for your tests, that's
all.

thanks,

greg k-h