On Wed, Apr 29, 2020 at 06:36:32AM -0700, Matthew Wilcox wrote: > From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx> > > 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 Note that you have 107 pages on LRU. It is only head pages. With order-5 pages it is over 13MiB. Looks like everything is fine. > 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 > -- Kirill A. Shutemov
