linux-kernel - Re: [PATCH 01/40] lib/string_helpers: Drop space in string_get

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Message-ID: <ZFIJeSv9xn9qnMzg@moria.home.lan>
Date:   Wed, 3 May 2023 03:12:57 -0400
From:   Kent Overstreet <kent.overstreet@...ux.dev>
To:     Andy Shevchenko <andy.shevchenko@...il.com>
Cc:     James Bottomley <James.Bottomley@...senpartnership.com>,
        Suren Baghdasaryan <surenb@...gle.com>,
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        Jason Wang <jasowang@...hat.com>,
        Noralf Trï¿½nnes <noralf@...nnes.org>
Subject: Re: [PATCH 01/40] lib/string_helpers: Drop space in
 string_get_size's output

On Wed, May 03, 2023 at 09:30:11AM +0300, Andy Shevchenko wrote:
> On Wed, May 3, 2023 at 5:07 AM Kent Overstreet
> <kent.overstreet@...ux.dev> wrote:
> > On Tue, May 02, 2023 at 06:19:27PM +0300, Andy Shevchenko wrote:
> > > On Tue, May 2, 2023 at 9:22 AM Kent Overstreet
> > > <kent.overstreet@...ux.dev> wrote:
> > > > On Tue, May 02, 2023 at 08:33:57AM +0300, Andy Shevchenko wrote:
> > > > > Actually instead of producing zillions of variants, do a %p extension
> > > > > to the printf() and that's it. We have, for example, %pt with T and
> > > > > with space to follow users that want one or the other variant. Same
> > > > > can be done with string_get_size().
> > > >
> > > > God no.
> > >
> > > Any elaboration what's wrong with that?
> >
> > I'm really not a fan of %p extensions in general (they are what people
> > reach for because we can't standardize on a common string output API),
> 
> The whole story behind, for example, %pt is to _standardize_ the
> output of the same stanza in the kernel.

Wtf does this have to do with the rest of the discussion? The %p thing
seems like a total non sequitar and a distraction.

I'm not getting involved with that. All I'm interested in is fixing the
memory allocation profiling output to make it more usable.

> > but when we'd be passing it bare integers the lack of type safety would
> > be a particularly big footgun.
> 
> There is no difference to any other place in the kernel where we can
> shoot into our foot.

Yeah, no, absolutely not. Passing different size integers to
string_get_size() is fine; passing pointers to different size integers
to a %p extension will explode and the compiler won't be able to warn.

> 
> > > God no for zillion APIs for almost the same. Today you want space,
> > > tomorrow some other (special) delimiter.
> >
> > No, I just want to delete the space and output numbers the same way
> > everyone else does. And if we are stuck with two string_get_size()
> > functions, %p extensions in no way improve the situation.
> 
> I think it's exactly for the opposite, i.e. standardize that output
> once and for all.

So, are you dropping your NACK then, so we can standardize the kernel on
the way everything else does it?