From: "Matthew Wilcox (Oracle)" <[email protected]> This patch set does not pass xfstests. Test at your own risk. It is based on the readahead rewrite which is in Andrew's tree. The large pages somehow manage to fall off the LRU, so the test VM quickly runs out of memory and freezes. To reproduce:
# mkfs.xfs /dev/sdb && mount /dev/sdb /mnt && dd if=/dev/zero bs=1M count=2048 of=/mnt/bigfile && sync && sleep 2 && sync && echo 1 >/proc/sys/vm/drop_caches # /host/home/willy/kernel/xarray-2/tools/vm/page-types | grep thp 0x0000000000401800 511 1 ___________Ma_________t____________________ mmap,anonymous,thp 0x0000000000405868 1 0 ___U_lA____Ma_b_______t____________________ uptodate,lru,active,mmap,anonymous,swapbacked,thp # dd if=/mnt/bigfile of=/dev/null bs=2M count=5 # /host/home/willy/kernel/xarray-2/tools/vm/page-types | grep thp 0x0000000000400000 2516 9 ______________________t____________________ thp 0x0000000000400028 1 0 ___U_l________________t____________________ uptodate,lru,thp 0x000000000040006c 106 0 __RU_lA_______________t____________________ referenced,uptodate,lru,active,thp 0x0000000000400228 1 0 ___U_l___I____________t____________________ uptodate,lru,reclaim,thp 0x0000000000401800 511 1 ___________Ma_________t____________________ mmap,anonymous,thp 0x0000000000405868 1 0 ___U_lA____Ma_b_______t____________________ uptodate,lru,active,mmap,anonymous,swapbacked,thp The principal idea here is that a large part of the overhead in dealing with individual pages is that there's just so darned many of them. We would be better off dealing with fewer, larger pages, even if they don't get to be the size necessary for the CPU to use a larger TLB entry. Matthew Wilcox (Oracle) (24): mm: Allow hpages to be arbitrary order mm: Introduce thp_size mm: Introduce thp_order mm: Introduce offset_in_thp fs: Add a filesystem flag for large pages fs: Introduce i_blocks_per_page fs: Make page_mkwrite_check_truncate thp-aware fs: Support THPs in zero_user_segments bio: Add bio_for_each_thp_segment_all iomap: Support arbitrarily many blocks per page iomap: Support large pages in iomap_adjust_read_range iomap: Support large pages in read paths iomap: Support large pages in write paths iomap: Inline data shouldn't see large pages xfs: Support large pages mm: Make prep_transhuge_page return its argument mm: Add __page_cache_alloc_order mm: Allow large pages to be added to the page cache mm: Allow large pages to be removed from the page cache mm: Remove page fault assumption of compound page size mm: Add DEFINE_READAHEAD mm: Make page_cache_readahead_unbounded take a readahead_control mm: Make __do_page_cache_readahead take a readahead_control mm: Add large page readahead William Kucharski (1): mm: Align THP mappings for non-DAX drivers/nvdimm/btt.c | 4 +- drivers/nvdimm/pmem.c | 6 +- fs/ext4/verity.c | 4 +- fs/f2fs/verity.c | 4 +- fs/iomap/buffered-io.c | 110 ++++++++++++++++-------------- fs/jfs/jfs_metapage.c | 2 +- fs/xfs/xfs_aops.c | 4 +- fs/xfs/xfs_super.c | 2 +- include/linux/bio.h | 13 ++++ include/linux/bvec.h | 23 +++++++ include/linux/fs.h | 1 + include/linux/highmem.h | 15 +++-- include/linux/huge_mm.h | 25 +++++-- include/linux/mm.h | 97 ++++++++++++++------------- include/linux/pagemap.h | 62 ++++++++++++++--- mm/filemap.c | 60 ++++++++++++----- mm/highmem.c | 62 ++++++++++++++++- mm/huge_memory.c | 49 ++++++-------- mm/internal.h | 13 ++-- mm/memory.c | 7 +- mm/page_io.c | 2 +- mm/page_vma_mapped.c | 4 +- mm/readahead.c | 145 ++++++++++++++++++++++++++++++---------- 23 files changed, 485 insertions(+), 229 deletions(-) -- 2.26.2
