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On 6/25/26 2:22 PM, David Hildenbrand (Arm) wrote: > On 6/24/26 12:20, Sarthak Sharma wrote: >> finish_fault() currently has a goto fallback implementation >> where we try to map a large folio with PTEs. If that cannot be >> installed, we goto fallback and go through the fallback mapping >> path again. This looks weird and is tough to comprehend. >> >> Remove the goto fallback implementation and try to map the >> whole folio if allowed. If the whole folio cannot be mapped, >> fall back to single page mapping without repeating the whole >> function. >> >> The cleanup of finish_fault() was suggested by David in [1]. >> >> [1] https://lore.kernel.org/all/3684c55a-6581-4731-b94a-19526f455a1e@kernel.org/ >> >> Suggested-by: David Hildenbrand (Arm) >> Signed-off-by: Sarthak Sharma >> --- >> Tested this patch by running mm selftests on baseline and patched 7.1 >> kernels. No regressions were observed. > > This goes into the right direction, but I think we can do better. > > For example, we know that we always have to fallback to a single PTE with > userfaultfd (incl. not mapping a PMD-sized folio by PMDs). > > Let me find some time to play with this myself. > I intended this patch to be just a refactor to get rid of the goto fallback mechanism and make the VMA and PTE table bound checks easier to read. But yeah I agree that we can work on cases like you mentioned about userfaultfd. Thanks for the feedback.