Managing memory in 4KiB pages is a serious overhead. Many benchmarks benefit from a larger "page size". As an example, an earlier iteration of this idea which used compound pages (and wasn't particularly tuned) got a 7% performance boost when compiling the kernel. Using compound pages or THPs exposes a weakness of our type system. Functions are often unprepared for compound pages to be passed to them, and may only act on PAGE_SIZE chunks. Even functions which are aware of compound pages may expect a head page, and do the wrong thing if passed a tail page. We also waste a lot of instructions ensuring that we're not looking at a tail page. Almost every call to PageFoo() contains one or more hidden calls to compound_head(). This also happens for get_page(), put_page() and many more functions. This patch series uses a new type, the struct folio, to manage memory. It converts enough of the page cache, iomap and XFS to use folios instead of pages, and then adds support for multi-page folios. It passes xfstests (running on XFS) with no regressions compared to v5.14-rc1. Git: https://git.infradead.org/users/willy/pagecache.git/shortlog/refs/tags/folio_13 Matthew Wilcox (Oracle) (137): mm: Convert get_page_unless_zero() to return bool mm: Introduce struct folio mm: Add folio_pgdat(), folio_zone() and folio_zonenum() mm/vmstat: Add functions to account folio statistics mm/debug: Add VM_BUG_ON_FOLIO() and VM_WARN_ON_ONCE_FOLIO() mm: Add folio reference count functions mm: Add folio_put() mm: Add folio_get() mm: Add folio_try_get_rcu() mm: Add folio flag manipulation functions mm/lru: Add folio LRU functions mm: Handle per-folio private data mm/filemap: Add folio_index(), folio_file_page() and folio_contains() mm/filemap: Add folio_next_index() mm/filemap: Add folio_pos() and folio_file_pos() mm/util: Add folio_mapping() and folio_file_mapping() mm/filemap: Add folio_unlock() mm/filemap: Add folio_lock() mm/filemap: Add folio_lock_killable() mm/filemap: Add __folio_lock_async() mm/filemap: Add folio_wait_locked() mm/filemap: Add __folio_lock_or_retry() mm/swap: Add folio_rotate_reclaimable() mm/filemap: Add folio_end_writeback() mm/writeback: Add folio_wait_writeback() mm/writeback: Add folio_wait_stable() mm/filemap: Add folio_wait_bit() mm/filemap: Add folio_wake_bit() mm/filemap: Convert page wait queues to be folios mm/filemap: Add folio private_2 functions fs/netfs: Add folio fscache functions mm: Add folio_mapped() mm: Add folio_nid() mm/memcg: Remove 'page' parameter to mem_cgroup_charge_statistics() mm/memcg: Use the node id in mem_cgroup_update_tree() mm/memcg: Remove soft_limit_tree_node() mm/memcg: Convert memcg_check_events to take a node ID mm/memcg: Add folio_memcg() and related functions mm/memcg: Convert commit_charge() to take a folio mm/memcg: Convert mem_cgroup_charge() to take a folio mm/memcg: Convert uncharge_page() to uncharge_folio() mm/memcg: Convert mem_cgroup_uncharge() to take a folio mm/memcg: Convert mem_cgroup_migrate() to take folios mm/memcg: Convert mem_cgroup_track_foreign_dirty_slowpath() to folio mm/memcg: Add folio_memcg_lock() and folio_memcg_unlock() mm/memcg: Convert mem_cgroup_move_account() to use a folio mm/memcg: Add folio_lruvec() mm/memcg: Add folio_lruvec_lock() and similar functions mm/memcg: Add folio_lruvec_relock_irq() and folio_lruvec_relock_irqsave() mm/workingset: Convert workingset_activation to take a folio mm: Add folio_pfn() mm: Add folio_raw_mapping() mm: Add flush_dcache_folio() mm: Add kmap_local_folio() mm: Add arch_make_folio_accessible() mm: Add folio_young() and folio_idle() mm/swap: Add folio_activate() mm/swap: Add folio_mark_accessed() mm/rmap: Add folio_mkclean() mm/migrate: Add folio_migrate_mapping() mm/migrate: Add folio_migrate_flags() mm/migrate: Add folio_migrate_copy() mm/writeback: Rename __add_wb_stat() to wb_stat_mod() flex_proportions: Allow N events instead of 1 mm/writeback: Change __wb_writeout_inc() to __wb_writeout_add() mm/writeback: Add __folio_end_writeback() mm/writeback: Add folio_start_writeback() mm/writeback: Add folio_mark_dirty() mm/writeback: Add __folio_mark_dirty() mm/writeback: Add filemap_dirty_folio() mm/writeback: Add folio_account_cleaned() mm/writeback: Add folio_cancel_dirty() mm/writeback: Add folio_clear_dirty_for_io() mm/writeback: Add folio_account_redirty() mm/writeback: Add folio_redirty_for_writepage() mm/filemap: Add i_blocks_per_folio() mm/filemap: Add folio_mkwrite_check_truncate() mm/filemap: Add readahead_folio() mm/workingset: Convert workingset_refault() to take a folio mm: Add folio_evictable() mm/lru: Convert __pagevec_lru_add_fn to take a folio mm/lru: Add folio_add_lru() mm/page_alloc: Add folio allocation functions mm/filemap: Add filemap_alloc_folio mm/filemap: Add filemap_add_folio() mm/filemap: Convert mapping_get_entry to return a folio mm/filemap: Add filemap_get_folio mm/filemap: Add FGP_STABLE block: Add bio_add_folio() block: Add bio_for_each_folio_all() iomap: Convert to_iomap_page to take a folio iomap: Convert iomap_page_create to take a folio iomap: Convert iomap_page_release to take a folio iomap: Convert iomap_releasepage to use a folio iomap: Convert iomap_invalidatepage to use a folio iomap: Pass the iomap_page into iomap_set_range_uptodate iomap: Use folio offsets instead of page offsets iomap: Convert bio completions to use folios iomap: Convert readahead and readpage to use a folio iomap: Convert iomap_page_mkwrite to use a folio iomap: Convert iomap_write_begin and iomap_write_end to folios iomap: Convert iomap_read_inline_data to take a folio iomap: Convert iomap_write_end_inline to take a folio iomap: Convert iomap_add_to_ioend to take a folio iomap: Convert iomap_do_writepage to use a folio iomap: Convert iomap_migrate_page to use folios mm/filemap: Convert page_cache_delete to take a folio mm/filemap: Convert unaccount_page_cache_page to filemap_unaccount_folio mm/filemap: Add filemap_remove_folio and __filemap_remove_folio mm/filemap: Convert find_get_entry to return a folio mm/filemap: Convert filemap_get_read_batch to use folios mm/filemap: Convert find_get_pages_contig to folios mm/filemap: Convert filemap_read_page to take a folio mm/filemap: Convert filemap_create_page to folio mm/filemap: Convert filemap_range_uptodate to folios mm/filemap: Convert filemap_fault to folio mm/filemap: Add read_cache_folio and read_mapping_folio mm/filemap: Convert filemap_get_pages to use folios mm/filemap: Convert page_cache_delete_batch to folios mm/filemap: Remove PageHWPoison check from next_uptodate_page() mm/filemap: Use folios in next_uptodate_page mm/filemap: Use a folio in filemap_map_pages fs: Convert vfs_dedupe_file_range_compare to folios mm/truncate,shmem: Handle truncates that split THPs mm/filemap: Return only head pages from find_get_entries mm: Use multi-index entries in the page cache iomap: Support multi-page folios in invalidatepage xfs: Support THPs mm/truncate: Convert invalidate_inode_pages2_range to folios mm/truncate: Fix invalidate_complete_page2 for THPs mm/vmscan: Free non-shmem THPs without splitting them mm: Fix READ_ONLY_THP warning mm: Support arbitrary THP sizes mm/filemap: Allow multi-page folios to be added to the page cache mm/vmscan: Optimise shrink_page_list for smaller THPs mm/readahead: Convert page_cache_async_ra() to take a folio mm/readahead: Add multi-page folio readahead Documentation/core-api/cachetlb.rst | 6 + Documentation/core-api/mm-api.rst | 4 + Documentation/filesystems/netfs_library.rst | 2 + arch/nds32/include/asm/cacheflush.h | 1 + block/bio.c | 21 + fs/afs/write.c | 9 +- fs/cachefiles/rdwr.c | 16 +- fs/io_uring.c | 2 +- fs/iomap/buffered-io.c | 524 ++++---- fs/jfs/jfs_metapage.c | 1 + fs/remap_range.c | 116 +- fs/xfs/xfs_aops.c | 11 +- fs/xfs/xfs_super.c | 3 +- include/asm-generic/cacheflush.h | 6 + include/linux/backing-dev.h | 6 +- include/linux/bio.h | 46 +- include/linux/flex_proportions.h | 9 +- include/linux/gfp.h | 22 +- include/linux/highmem-internal.h | 11 + include/linux/highmem.h | 38 + include/linux/huge_mm.h | 23 +- include/linux/ksm.h | 4 +- include/linux/memcontrol.h | 218 ++-- include/linux/migrate.h | 4 + include/linux/mm.h | 266 +++- include/linux/mm_inline.h | 85 +- include/linux/mm_types.h | 77 ++ include/linux/mmdebug.h | 20 + include/linux/netfs.h | 77 +- include/linux/page-flags.h | 267 ++-- include/linux/page_idle.h | 99 +- include/linux/page_owner.h | 8 +- include/linux/page_ref.h | 158 ++- include/linux/pagemap.h | 615 +++++---- include/linux/rmap.h | 10 +- include/linux/swap.h | 17 +- include/linux/vmstat.h | 107 ++ include/linux/writeback.h | 9 +- include/trace/events/writeback.h | 8 +- kernel/bpf/verifier.c | 2 +- kernel/events/uprobes.c | 3 +- lib/flex_proportions.c | 28 +- mm/Makefile | 2 +- mm/compaction.c | 4 +- mm/filemap.c | 1285 +++++++++---------- mm/folio-compat.c | 147 +++ mm/huge_memory.c | 27 +- mm/internal.h | 40 +- mm/khugepaged.c | 20 +- mm/ksm.c | 34 +- mm/memcontrol.c | 323 +++-- mm/memory-failure.c | 2 +- mm/memory.c | 20 +- mm/mempolicy.c | 10 + mm/memremap.c | 2 +- mm/migrate.c | 246 ++-- mm/mlock.c | 3 +- mm/page-writeback.c | 447 ++++--- mm/page_alloc.c | 14 +- mm/page_io.c | 4 +- mm/page_owner.c | 10 +- mm/readahead.c | 108 +- mm/rmap.c | 14 +- mm/shmem.c | 115 +- mm/swap.c | 180 +-- mm/swap_state.c | 2 +- mm/swapfile.c | 8 +- mm/truncate.c | 193 +-- mm/userfaultfd.c | 2 +- mm/util.c | 92 +- mm/vmscan.c | 15 +- mm/workingset.c | 44 +- 72 files changed, 3822 insertions(+), 2550 deletions(-) create mode 100644 mm/folio-compat.c -- 2.30.2
