Re: [PATCH v4 3/3] unzstd: make helper symbols static

[Julien Grall <julien@xxxxxxx>]

Hi Jan,

On 06/05/2021 07:21, Jan Beulich wrote:
> On 05.05.2021 19:35, Julien Grall wrote:
> > On 29/04/2021 14:26, Jan Beulich wrote:
> > > On 29.04.2021 13:27, Julien Grall wrote:
> > > > On 21/04/2021 11:22, Jan Beulich wrote:
> > > > > While for the original library's purposes these functions of course want
> > > > > to be externally exposed, we don't need this, and we also don't want
> > > > > this both to prevent unintended use and to keep the name space tidy.
> > > > > (When functions have no callers at all, wrap them with a suitable
> > > > > #ifdef.) This has the added benefit of reducing the resulting binary
> > > > > size - while this is all .init code, it's still desirable to not carry
> > > > > dead code.
> > > > So I understand the desire to keep the code close to Linux and removing
> > > > the dead code. However I am still not convinced that the approach taken
> > > > is actually worth the amount of memory saved.
> > > >
> > > > How much memory are we talking about here?
> > > There are no (runtime) memory savings, as is being said by the
> > > description. There are savings on the image and symbol table sizes
> > > (see below - .*.0/ holding files as produced without the patch
> > > applied, while .*.1/ holding output with it in place), the image
> > > size reduction part of which is - as also expressed by the
> > > description - a nice side effect, but not the main motivation for
> > > the change.
> > Thanks for the providing the information. I have misunderstood your
> > original intention.
> >
> > Reading them again, I have to admit this doesn't really change my view
> > here. You are trading a smaller name space or prevent unintended use
> > (not clear what would be wrong to call them) to code
> > maintenability/readability.
> Well, I mean mainly the usual issue of us, short of having Linux-like
> section reference checking, being at risk of calling __init functions
> from non-__init code.
Right, we are rely on the review to not mix the tow. In the past, I have 
successfully used the Linux script on Xen binary. It might be a good 
idea to import a cut-down version in Xen.
Cheers,

--
Julien Grall