Re: [PATCH v2 1/2] tracing: ring-buffer: Have the ring buffer code do the vmap of physical memory

[Linus Torvalds]

 On Mon, 31 Mar 2025 at 17:38, Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> So *this* is the kind of "bad in a different way" I could imagine:
> things that probably should be cleaned up and be available to generic
> code, but very few people have cared, and so they are used in ad-hoc
> places and haven't been sufficiently generalized and cleaned up.

Of course, the good news is that (a) few people care - which is why we
are in this situation - and (b) the people who *do* care about these
issues tend to be both responsible and responsive.

So not some unfixable morass, more of a "one or two architectures may
care, and we might have to extend interfaces that haven't been used
this way before".

For example, just adding flush_dcache_range() into
include/asm-generic/cacheflush.h should be more-or-less trivial, with
the same kinds of "architectures can make clear they have their own
optimized version".

              Linus