Re: [PATCH] thp: Disable THP if THP isn't supported by kernel
"H.J. Lu" <[email protected]>
| Newsgroups | gmane.comp.lib.glibc.alpha |
|---|---|
| Message-ID | <CAMe9rOpzAUywYMAJPz0N9Qpq2Nk_HiGSHJ8Edf+6_8qb1xFYRg@mail.gmail.com> |
On Thu, Jul 23, 2026 at 2:17 AM Wilco Dijkstra <[email protected]> wrote: > > Hi HJ, > > > Since DL_MAP_DEFAULT_THP_PAGESIZE is defined for x86-64, THP control > > is to set to madvise by default. If THP is disabled in x86-64 kernel, > > madvise (..., MADV_HUGEPAGE) returns -EINVAL to indicate that THP isn't > > supported. Add _dl_thp_madvise to disable THP in this case. This > > fixes BZ #34348. > > Are there enough calls in the loader that this is worthwhile? > > More importantly, does this actually work? I always get 0 result from madvise > calls irrespectively of the madvise settings... Does it need a new kernel or is > this target specific? You need to run it under a kernel without THP support. That is there is no /sys/kernel/mm/transparent_hugepage/enabled. > If we can get it to work, it could be useful in madvise_thp() since there are > potentially millions madvise calls. > > Cheers, > Wilco -- H.J.