Here is my implementation of huge pages support in tmpfs/shmem. It's more or less complete. I'm comfortable enough with this to run my workstation. And it hasn't crashed so far. :) The main difference with Hugh's approach[1] is that I continue with compound pages, where Hugh invents new way couple pages: team pages. I believe THP refcounting rework made team pages unnecessary: compound page are flexible enough to serve needs of page cache. Many ideas and some patches were stolen from Hugh's patchset. Having this patchset around was very helpful. I will continue with code validation. I would expect mlock require some more attention. Please, review and test the code. Git tree: git://git.kernel.org/pub/scm/linux/kernel/git/kas/linux.git hugetmpfs/v2 == Patchset overview == [01/28] I've posted the patch last night. I stepped on the bug during my testing of huge tmpfs, but I think DAX has the same problem, so it should be applied now. [02-05/28] These patches also where posted separately. They simplify split_huge_page() code with speed trade off. I'm not sure if they should go upstream, but they make my life easier for now. Patches were slightly adjust to handle file pages too. [06-11/28] Rework fault path and rmap to handle file pmd. Unlike DAX with vm_ops->pmd_fault, we don't need to ask filesystem twice -- first for huge page and then for small. If ->fault happend to return huge page and VMA is suitable for mapping it as huge, we would do so. [12-20/28] Various preparation of THP core for file pages. [21-25/28] Various preparation of MM core for file pages. [26-28/28] And finally, bring huge pages into tmpfs/shmem. Two of three patches came from Hugh's patchset. :) [1] http://lkml.kernel.org/g/alpine.LSU.2.11.1502201941340.14414@eggly.anvils Hugh Dickins (2): shmem: prepare huge=N mount option and /proc/sys/vm/shmem_huge shmem: get_unmapped_area align huge page Kirill A. Shutemov (26): thp, dax: do not try to withdraw pgtable from non-anon VMA rmap: introduce rmap_walk_locked() rmap: extend try_to_unmap() to be usable by split_huge_page() mm: make remove_migration_ptes() beyond mm/migration.c thp: rewrite freeze_page()/unfreeze_page() with generic rmap walkers mm: do not pass mm_struct into handle_mm_fault mm: introduce fault_env mm: postpone page table allocation until do_set_pte() rmap: support file thp mm: introduce do_set_pmd() mm, rmap: account file thp pages thp, vmstats: add counters for huge file pages thp: support file pages in zap_huge_pmd() thp: handle file pages in split_huge_pmd() thp: handle file COW faults thp: handle file pages in mremap() thp: skip file huge pmd on copy_huge_pmd() thp: prepare change_huge_pmd() for file thp thp: run vma_adjust_trans_huge() outside i_mmap_rwsem thp: file pages support for split_huge_page() vmscan: split file huge pages before paging them out page-flags: relax policy for PG_mappedtodisk and PG_reclaim radix-tree: implement radix_tree_maybe_preload_order() filemap: prepare find and delete operations for huge pages truncate: handle file thp shmem: add huge pages support Documentation/filesystems/Locking | 10 +- arch/alpha/mm/fault.c | 2 +- arch/arc/mm/fault.c | 2 +- arch/arm/mm/fault.c | 2 +- arch/arm64/mm/fault.c | 2 +- arch/avr32/mm/fault.c | 2 +- arch/cris/mm/fault.c | 2 +- arch/frv/mm/fault.c | 2 +- arch/hexagon/mm/vm_fault.c | 2 +- arch/ia64/mm/fault.c | 2 +- arch/m32r/mm/fault.c | 2 +- arch/m68k/mm/fault.c | 2 +- arch/metag/mm/fault.c | 2 +- arch/microblaze/mm/fault.c | 2 +- arch/mips/mm/fault.c | 2 +- arch/mn10300/mm/fault.c | 2 +- arch/nios2/mm/fault.c | 2 +- arch/openrisc/mm/fault.c | 2 +- arch/parisc/mm/fault.c | 2 +- arch/powerpc/mm/copro_fault.c | 2 +- arch/powerpc/mm/fault.c | 2 +- arch/s390/mm/fault.c | 2 +- arch/score/mm/fault.c | 2 +- arch/sh/mm/fault.c | 2 +- arch/sparc/mm/fault_32.c | 4 +- arch/sparc/mm/fault_64.c | 2 +- arch/tile/mm/fault.c | 2 +- arch/um/kernel/trap.c | 2 +- arch/unicore32/mm/fault.c | 2 +- arch/x86/mm/fault.c | 2 +- arch/xtensa/mm/fault.c | 2 +- drivers/base/node.c | 10 +- drivers/char/mem.c | 24 ++ drivers/iommu/amd_iommu_v2.c | 2 +- drivers/iommu/intel-svm.c | 2 +- fs/proc/meminfo.c | 5 +- fs/userfaultfd.c | 22 +- include/linux/huge_mm.h | 29 +- include/linux/mm.h | 33 +- include/linux/mmzone.h | 3 +- include/linux/page-flags.h | 6 +- include/linux/radix-tree.h | 1 + include/linux/rmap.h | 8 +- include/linux/shmem_fs.h | 18 +- include/linux/userfaultfd_k.h | 8 +- include/linux/vm_event_item.h | 7 + ipc/shm.c | 6 +- kernel/sysctl.c | 12 + lib/radix-tree.c | 70 +++- mm/filemap.c | 220 +++++++---- mm/gup.c | 7 +- mm/huge_memory.c | 714 ++++++++++++++-------------------- mm/internal.h | 20 +- mm/ksm.c | 3 +- mm/memory.c | 796 +++++++++++++++++++++----------------- mm/mempolicy.c | 4 +- mm/migrate.c | 17 +- mm/mmap.c | 20 +- mm/mremap.c | 22 +- mm/nommu.c | 3 +- mm/page-writeback.c | 1 + mm/rmap.c | 125 ++++-- mm/shmem.c | 493 +++++++++++++++++++---- mm/swap.c | 2 + mm/truncate.c | 22 +- mm/util.c | 6 + mm/vmscan.c | 15 +- mm/vmstat.c | 3 + 68 files changed, 1727 insertions(+), 1104 deletions(-) -- 2.7.0 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. 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