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See Closes: tag. This happens because the high order pages >> must be gotten from the buddy but then because they are split to >> order-0, when they are freed they are freed to the order-0 pcp. >> Previously allocation was for order-0 pages so they were recycled from >> the pcp. >> >> It would be preferable if when vmalloc allocates an (e.g.) order-3 page >> that it also frees that order-3 page to the order-3 pcp, then the >> regression could be removed. >> >> So let's do exactly that; update stats separately first as coalescing is >> hard to do correctly without complexity. Use free_pages_bulk() which uses >> the new __free_contig_range() API to batch-free contiguous ranges of pfns. >> This not only removes the regression, but significantly improves >> performance of vfree beyond the baseline. >> >> A selection of test_vmalloc benchmarks running on arm64 server class >> system. mm-new is the baseline. Commit a06157804399 ("mm/vmalloc: request >> large order pages from buddy allocator") was added in v6.19-rc1 where we >> see regressions. Then with this change performance is much better. (>0 >> is faster, <0 is slower, (R)/(I) = statistically significant >> Regression/Improvement): >> >> +-----------------+----------------------------------------------------------+-------------------+--------------------+ >> | Benchmark | Result Class | mm-new | this series | >> +=================+==========================================================+===================+====================+ >> | micromm/vmalloc | fix_align_alloc_test: p:1, h:0, l:500000 (usec) | 1331843.33 | (I) 67.17% | >> | | fix_size_alloc_test: p:1, h:0, l:500000 (usec) | 415907.33 | -5.14% | >> | | fix_size_alloc_test: p:4, h:0, l:500000 (usec) | 755448.00 | (I) 53.55% | >> | | fix_size_alloc_test: p:16, h:0, l:500000 (usec) | 1591331.33 | (I) 57.26% | >> | | fix_size_alloc_test: p:16, h:1, l:500000 (usec) | 1594345.67 | (I) 68.46% | >> | | fix_size_alloc_test: p:64, h:0, l:100000 (usec) | 1071826.00 | (I) 79.27% | >> | | fix_size_alloc_test: p:64, h:1, l:100000 (usec) | 1018385.00 | (I) 84.17% | >> | | fix_size_alloc_test: p:256, h:0, l:100000 (usec) | 3970899.67 | (I) 77.01% | >> | | fix_size_alloc_test: p:256, h:1, l:100000 (usec) | 3821788.67 | (I) 89.44% | >> | | fix_size_alloc_test: p:512, h:0, l:100000 (usec) | 7795968.00 | (I) 82.67% | >> | | fix_size_alloc_test: p:512, h:1, l:100000 (usec) | 6530169.67 | (I) 118.09% | >> | | full_fit_alloc_test: p:1, h:0, l:500000 (usec) | 626808.33 | -0.98% | >> | | kvfree_rcu_1_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 532145.67 | -1.68% | >> | | kvfree_rcu_2_arg_vmalloc_test: p:1, h:0, l:500000 (usec) | 537032.67 | -0.96% | >> | | long_busy_list_alloc_test: p:1, h:0, l:500000 (usec) | 8805069.00 | (I) 74.58% | >> | | pcpu_alloc_test: p:1, h:0, l:500000 (usec) | 500824.67 | 4.35% | >> | | random_size_align_alloc_test: p:1, h:0, l:500000 (usec) | 1637554.67 | (I) 76.99% | >> | | random_size_alloc_test: p:1, h:0, l:500000 (usec) | 4556288.67 | (I) 72.23% | >> | | vm_map_ram_test: p:1, h:0, l:500000 (usec) | 107371.00 | -0.70% | >> +-----------------+----------------------------------------------------------+-------------------+--------------------+ >> >> Fixes: a06157804399 ("mm/vmalloc: request large order pages from buddy allocator") >> Closes: https://lore.kernel.org/all/66919a28-bc81-49c9-b68f-dd7c73395a0d@arm.com/ >> Acked-by: Zi Yan >> Signed-off-by: Ryan Roberts >> Co-developed-by: Muhammad Usama Anjum >> Signed-off-by: Muhammad Usama Anjum > > Acked-by: Vlastimil Babka (SUSE) Thank you. But as the implementation of free_pages_bulk() has changed to using num_pages_contiguous(), I cannot take this tag. Please review the next version again. > > -- --- Thanks, Usama