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a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=wKuvFiaSGQ0qltdbU6+NXLB8nM8=:19 a=Ol13hO9ccFRV9qXi2t6ftBPywas=:19 a=xqWC_Br6kY4A:10 a=kj9zAlcOel0A:10 a=2OwXVqhp2XgA:10 a=GoEa3M9JfhUA:10 a=ErywnbMd53imLDUG0G4A:9 a=CjuIK1q_8ugA:10 X-Proofpoint-ORIG-GUID: Tu_7MMTrAasJoPrkZLMaztIeq7plQcO9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA4MDA4MCBTYWx0ZWRfXw3rlQ9yeaZMo 7RUS2eudswQXULpROGXCF5ejj098zKhzgmlIpH5AKTko8J7rI6jJ3c1p0tK2ZO2WOB18VqxnRrB 44SG6VbvvKPtyAQXTqRegPbAujUNu7Pz7X+sENpccetL9qPop9J+T2I2QGyccK2ltV/vVmQGWcy dgFA85EYfoidNNTCm0eFYNkSVZKma60nZm53vzWwwoKwJdLUZ1/yBOz51e4hAaRY+8LDb78QmdE 4fcl5dxKMoAHskqxUtya4Vb44KFcjSX1Asw5vS3Xm1gx4m13LC46yb7FfOBupMCq/iiIpi2ym8C MM3g6rOwtlQz69jmpa1YqttukbWj4itJHsosJ8WF9mEdu/ely4MrD60a94JA4fao8oLU5OBf8iC Y8sRCPMnER2Vpn9JoeZpLuakLzQoTx5+cwFqr/klcWa78XQ/y6RIMAAEwARlYPESnygP6rM/ X-Proofpoint-GUID: Tu_7MMTrAasJoPrkZLMaztIeq7plQcO9 On Fri, Aug 08, 2025 at 09:45:39AM +0200, David Hildenbrand wrote: > I am probably to blame here, because I think I rejected early to have > arm64-only optimization, assuming other arch could benefit here as well with > batching. But as it seems, batching in mremap() code really only serves the > cont-pte managing code, and the folio_pte_batch() is really entirely > unnecessary. > > In case of mprotect(), I think really only (a) NUMA and (b) anon-folio > write-upgrade required the folio. So it's a bit more tricky than mremap() > here where ... the folio is entirely irrelevant. > > One could detect the "anon write-upgrade possible" case early as well, and > only lookup the folio in that case, otherwise use the straight pte hint. > > So I think there is some room for further improvement. These are all great ideas and given we handle A/D correctly in mremap case due to get_and_clear_ptes() + additionally Ryan has hinted that it shouldn't be a big deal to lose the 'what if there are other batches/physically contiguous entries' logic, then your suggestion for simplification, that is - litearlly having mremap-folio_pte_batch() figure out the result from the pte batch hint - is probably the best way. We could RFC it and Dev could go check arm64 perf perhaps? Cheers, Lorenzo