[LTP] [PATCH v1 0/3] userfaultfd: Fix and remove compile-time TCONF handling

Petr Vorel pvorel@suse.cz
Mon Nov 28 19:42:09 CET 2022


> On 28.11.22 13:29, Martin Doucha wrote:
> > On 28. 11. 22 12:57, Petr Vorel wrote:
> > > Hi David,

> > > If I remember correctly the reason for runtime check was ppc64le
> > > missing userfaultfd minor fault support which needs to be check in runtime,
> > > right? [1]. At least this is how I understand Martin's suggestion [2] to replace
> > > compile time check with lapi. I'd state this reason at first commit message as
> > > it's not obvious.

> > The reason for runtime check is that the presence of the header file
> > does not guarantee that the kernel supports UFFD API. The reason for
> > LAPI is that we only care about actual kernel support, not build-time
> > header files.
Thx, agree. BTW I was thinking about compile time check #ifdef
UFFD_FEATURE_MINOR_SHMEM, but that's the same as ifdef HAVE_LINUX_USERFAULTFD_H.


> Right. Petr, do you still want a commit message state?

I can just add to commit message of the first commit the reason Martin reported:
ppc64le on kernel 5.14 does not seem to support userfaultfd minor fault.

(no need to resent new version).

Kind regards,
Petr



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