Hi Liam, On 6/13/2023 4:39 AM, Liam R. Howlett wrote: > Initial work on preallocations showed no regression in performance > during testing, but recently some users (both on [1] and off [android] > list) have reported that preallocating the worst-case number of nodes > has caused some slow down. This patch set addresses the number of > allocations in a few ways. > > During munmap() most munmap() operations will remove a single VMA, so > leverage the fact that the maple tree can place a single pointer at > range 0 - 0 without allocating. This is done by changing the index in > the 'sidetree'. > > Re-introduce the entry argument to mas_preallocate() so that a more > intelligent guess of the node count can be made. > > During development of v2 of this patch set, I also noticed that the > number of nodes being allocated for a rebalance was beyond what could > possibly be needed. This is addressed in patch 0008. > > Patches are in the following order: > 0001-0002: Testing framework for benchmarking some operations > 0003-0004: Reduction of maple node allocation in sidetree > 0005: Small cleanup of do_vmi_align_munmap() > 0006-0015: mas_preallocate() calculation change > 0016: Change the vma iterator order > > Changes since v1: > - Reduced preallocations for append and slot store - Thanks Peng Zhang > - Added patch to reduce node allocations for mas_rebalance() (patch 0008) > - Reduced resets during store setup to avoid duplicate walking (patch 0015) AIM9.page_test in my local env: before-preallocation: 763812 preallocation: 676600 preallocation fixup v2 (this patchset: 734060 For this specific test, the v2 patch works perfectly. Thanks. Regards Yin, Fengwei > > v1: https://lore.kernel.org/lkml/20230601021605.2823123-1-Liam.Howlett@xxxxxxxxxx/ > > [1] https://lore.kernel.org/linux-mm/202305061457.ac15990c-yujie.liu@xxxxxxxxx/ > > Liam R. Howlett (16): > maple_tree: Add benchmarking for mas_for_each > maple_tree: Add benchmarking for mas_prev() > mm: Move unmap_vmas() declaration to internal header > mm: Change do_vmi_align_munmap() side tree index > mm: Remove prev check from do_vmi_align_munmap() > maple_tree: Introduce __mas_set_range() > mm: Remove re-walk from mmap_region() > maple_tree: Adjust node allocation on mas_rebalance() > maple_tree: Re-introduce entry to mas_preallocate() arguments > mm: Use vma_iter_clear_gfp() in nommu > mm: Set up vma iterator for vma_iter_prealloc() calls > maple_tree: Move mas_wr_end_piv() below mas_wr_extend_null() > maple_tree: Update mas_preallocate() testing > maple_tree: Refine mas_preallocate() node calculations > maple_tree: Reduce resets during store setup > mm/mmap: Change vma iteration order in do_vmi_align_munmap() > > fs/exec.c | 1 + > include/linux/maple_tree.h | 23 ++++- > include/linux/mm.h | 4 - > lib/maple_tree.c | 121 ++++++++++++++++------ > lib/test_maple_tree.c | 74 +++++++++++++ > mm/internal.h | 40 ++++++-- > mm/memory.c | 19 ++-- > mm/mmap.c | 171 ++++++++++++++++--------------- > mm/nommu.c | 45 ++++---- > tools/testing/radix-tree/maple.c | 59 ++++++----- > 10 files changed, 364 insertions(+), 193 deletions(-) >
