Re: [PATCH v3 13/35] lib: add allocation tagging support for memory allocation profiling

Suren Baghdasaryan
2024-02-16T08:56:10Z

On Fri, Feb 16, 2024 at 12:50 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> On 2/13/24 23:38, Kees Cook wrote:
> > On Tue, Feb 13, 2024 at 02:35:29PM -0800, Suren Baghdasaryan wrote:
> >> On Tue, Feb 13, 2024 at 2:29 PM Darrick J. Wong <djwong@kernel.org> wrote:
> >> >
> >> > On Mon, Feb 12, 2024 at 05:01:19PM -0800, Suren Baghdasaryan wrote:
> >> > > On Mon, Feb 12, 2024 at 2:40 PM Kees Cook <keescook@chromium.org> wrote:
> >> > > >
> >> > > > On Mon, Feb 12, 2024 at 01:38:59PM -0800, Suren Baghdasaryan wrote:
> >> > > > > Introduce CONFIG_MEM_ALLOC_PROFILING which provides definitions to easily
> >> > > > > instrument memory allocators. It registers an "alloc_tags" codetag type
> >> > > > > with /proc/allocinfo interface to output allocation tag information when
> >> > > >
> >> > > > Please don't add anything new to the top-level /proc directory. This
> >> > > > should likely live in /sys.
> >> > >
> >> > > Ack. I'll find a more appropriate place for it then.
> >> > > It just seemed like such generic information which would belong next
> >> > > to meminfo/zoneinfo and such...
> >> >
> >> > Save yourself a cycle of "rework the whole fs interface only to have
> >> > someone else tell you no" and put it in debugfs, not sysfs. Wrangling
> >> > with debugfs is easier than all the macro-happy sysfs stuff; you don't
> >> > have to integrate with the "device" model; and there is no 'one value
> >> > per file' rule.
> >>
> >> Thanks for the input. This file used to be in debugfs but reviewers
> >> felt it belonged in /proc if it's to be used in production
> >> environments. Some distros (like Android) disable debugfs in
> >> production.
> >
> > FWIW, I agree debugfs is not right. If others feel it's right in /proc,
> > I certainly won't NAK -- it's just been that we've traditionally been
> > trying to avoid continuing to pollute the top-level /proc and instead
> > associate new things with something in /sys.
>
> Sysfs is really a "one value per file" thing though. /proc might be ok for a
> single overview file.

I'm preparing v4 and will keep the file it under /proc for now unless
there are strong objections.