Re: [RFC][PATCH] uprobe: support for private hugetlb mappings

David Hildenbrand
2024-04-22T09:39:40Z

On 19.04.24 20:37, Guillaume Morin wrote:
> libhugetlbfs, the Intel iodlr code both allow to remap .text onto a
> hugetlb private mapping. It's also pretty easy to do it manually.
> One drawback of using this functionality is the lack of support for
> uprobes (NOTE uprobe ignores shareable vmas)
>
> This patch adds support for private hugetlb mappings. It does require exposing
> some hugetlbfs innards and relies on copy_user_large_folio which is only
> available when CONFIG_HUGETLBFS is used so I had to use an ugly #ifdef
>
> If there is some interest in applying this patch in some form or
> another, I am open to any refactoring suggestions (esp getting rid the
> #ifdef in uprobes.c) . I tried to limit the
> amount of branching.

All that hugetlb special casing .... oh my. What's the benefit why we
should be interested in making that code less clean -- to phrase it in a
nice way ;) ?

Yes, libhugetlbfs exists. But why do we have to support uprobes with it?
Nobody cared until now, why care now?

--
Cheers,

David / dhildenb