On Thu, Oct 31, 2013 at 08:33:34AM -0700, William Roberts wrote:
> On Thu, Oct 31, 2013 at 8:28 AM, Richard Guy Briggs <rgb@redhat.com> wrote:
>
> > On Thu, Oct 31, 2013 at 08:24:11AM -0700, William Roberts wrote:
> > > On Thu, Oct 31, 2013 at 7:36 AM, Steve Grubb <sgrubb@redhat.com> wrote:
> > > > On Wednesday, October 30, 2013 01:18:13 PM William Roberts wrote:
> > > > > On Wed, Oct 30, 2013 at 12:42 PM, Steve Grubb <sgrubb@redhat.com> wrote:
> > > > > I have compiled kernels in the past with custom COMM widths, but
> > > > > the memory footprint goes up, at least here were not keeping a
> > > > > bunch of possibly unused data around in the kernel plus we're not
> > > > > allocating anything on the common case of it being turned off.
> > > >
> > > > I don't like the idea of fields appearing and disappearing. The
> > > > complaint is "comm" is meaningless. Let's fix that.
> > >
> > > Its not that the field is disappearing, its just whether or not you
> > > want the value printed out. cmdline=(null) vs cmdline="something".
> > > That's a trivial change of not making it dynamic which is what my
> > > first patch did but Richard Briggs suggested making it a dynamic
> > > feature and I was pretty ok with that.
> >
> > Ok, so how about both fields are always present, but have some keyword
> > that is printed that indicates it is a duplicate of the other field?
> >
> > Something like cmdline=(comm)
>
> How are you going to detect that cmdlne has changed, its a region of
> memory in userspace? We would have to cmp the values, and if we cannot
> detect the transition, this gets more expensive. Also, I have yet to
> see a case where the above statement is true, so it would be a very
> infrequent event.

Is it likely that those two point to the same region of memory?  If so,
just compare the pointers.

> However, their is a condition in my patch where an error will cause
> comm=(null) not to be printed, which could be
> viewed as a disappearing field.

Would it be useful if this condition were changed to print instead comm=(error)?

> > > William C Roberts
> >
> > - RGB
>
> William C Roberts

- RGB

--
Richard Guy Briggs <rbriggs@redhat.com>
Senior Software Engineer
Kernel Security
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