Messages in this thread | | | Date | Thu, 27 Feb 2014 17:45:24 +0100 | From | Oleg Nesterov <> | Subject | Re: + mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch added to -mm tree |
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On 02/26, Gerald Schaefer wrote: > > On Wed, 26 Feb 2014 19:06:03 +0100 > Oleg Nesterov <oleg@redhat.com> wrote: > > > It would be nice to also change thp_split_mm() to not not play with > > mm->def_flags, but I am not sure if we can do this. > > Hmm, I'm also wondering about this. Basically, we only need VM_NOHUGEPAGE > in vma->vm_flags, which is done for all existing vmas in thp_split_mm(). > But if there should be new vmas created afterwards, it would still be > necessary to also have VM_NOHUGEPAGE in mm->def_flags, because the > vm_flags for new vmas will be set via OR of mm->def_flags, e.g. in > do_brk() and do_mmap_pgoff().
Yes, exactly, this was my concern.
And while I know nothing about s390, it seems to me that huge pages should be forbidden for any vma if ->has_pgste was set.
> Anyway, this would then have to be a separate patch, to keep the > "revertability" of this hack.
Agreed. Thanks!
Oleg.
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