On 05/24/2017 12:39 PM, Mike Rapoport wrote:
quoted
Hm so the prctl does:
if (arg2)
me->mm->def_flags |= VM_NOHUGEPAGE;
else
me->mm->def_flags &= ~VM_NOHUGEPAGE;
That's rather lazy implementation IMHO. Could we change it so the flag
is stored elsewhere in the mm, and the code that decides to (not) use
THP will check both the per-vma flag and the per-mm flag?
I afraid I don't understand how that can help.
What we need is an ability to temporarily disable collapse of the pages in
VMAs that do not have VM_*HUGEPAGE flags set and that after we re-enable
THP, the vma->vm_flags for those VMAs will remain intact.
That's what I'm saying - instead of implementing the prctl flag via
mm->def_flags (which gets permanently propagated to newly created vma's
but e.g. doesn't affect already existing ones), it would be setting a
flag somewhere in mm, which khugepaged (and page faults) would check in
addition to the per-vma flags.
--
Sincerely yours,
Mike.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>