Hi All, This is a series to improve performance of process teardown, taking advantage of the fact that large folios are increasingly regularly pte-mapped in user space; supporting filesystems already use large folios for pagecache memory, and large folios for anonymous memory are (hopefully) on the horizon. See last patch for performance numbers, including measurements that show this approach doesn't regress (and actually improves a little bit) when all folios are small. The basic approach is to accumulate contiguous ranges of pages in the mmu_gather structure (instead of storing each individual page pointer), then take advantage of this internal format to efficiently batch rmap removal, swapcache removal and page release - see the commit messages for more details. This series replaces the previous approach I took at [1], which was much smaller in scope, only attempting to batch rmap removal for anon pages. Feedback was that I should do something more general that would also batch-remove pagecache pages from the rmap. But while designing that, I found it was also possible to improve swapcache removal and page release. Hopefully I haven't gone too far the other way now! Note that patch 1 is unchanged from that originl series. This series is based on mm-unstable (ad3232df3e41). I'm going to be out on holiday from the end of today, returning on 29th August. So responses will likely be patchy, as I'm terrified of posting to list from my phone! [1] https://lore.kernel.org/linux-mm/20230727141837.3386072-1-ryan.roberts@xxxxxxx/ Thanks, Ryan Ryan Roberts (4): mm: Implement folio_remove_rmap_range() mm/mmu_gather: generalize mmu_gather rmap removal mechanism mm/mmu_gather: Remove encoded_page infrastructure mm/mmu_gather: Store and process pages in contig ranges arch/s390/include/asm/tlb.h | 9 +-- include/asm-generic/tlb.h | 49 +++++++------- include/linux/mm.h | 11 +++- include/linux/mm_types.h | 34 +--------- include/linux/rmap.h | 2 + include/linux/swap.h | 6 +- mm/memory.c | 24 ++++--- mm/mmu_gather.c | 112 +++++++++++++++++++++++--------- mm/rmap.c | 125 +++++++++++++++++++++++++++--------- mm/swap.c | 99 ++++++++++++++++++++++++++-- mm/swap_state.c | 11 ++-- 11 files changed, 333 insertions(+), 149 deletions(-) -- 2.25.1
