Rosebush is a resizing, scalable, cache-aware, RCU optimised hash table. v2 has switched to fixed sized buckets. That considerably simplifies the code and removes the dilemma about whether to grow the bucket or grow the table. The layout of the bucket has changed to place all the hashes at the start of the bucket, optimising lookups (as it improves the chances that the hash we're looking for will be found in the first cacheline). Other changes: - Added rbh_destroy() - When we split a bucket, we now create two new buckets instead of only creating one and leaving the other one to be reallocated later - Added rbh_dump() to help debugging - Buildable in userspace as part of the radix tree testsuite - Dcache conversion I suspect the dcache conversion probably doesn't work with detached dentries. But it should be good enough for someone to run a performance benchmark ... v1 can be found at https://lore.kernel.org/all/20240222203726.1101861-1-willy@xxxxxxxxxxxxx/ This patch set can be found at http://git.infradead.org/?p=users/willy/pagecache.git;a=shortlog;h=refs/heads/rosebush aka git://git.infradead.org/users/willy/pagecache.git rosebush Matthew Wilcox (Oracle) (5): tools: Add kernel stubs needed for rosebush rosebush: Add new data structure rosebush: Add test suite tools: Add support for running rosebush tests in userspace dcache: Convert to use rosebush Documentation/core-api/index.rst | 1 + Documentation/core-api/rosebush.rst | 121 +++++ MAINTAINERS | 8 + fs/dcache.c | 152 ++---- include/linux/rosebush.h | 62 +++ lib/Kconfig.debug | 3 + lib/Makefile | 3 +- lib/rosebush.c | 654 +++++++++++++++++++++++ lib/test_rosebush.c | 140 +++++ tools/include/linux/compiler.h | 4 + tools/include/linux/compiler_types.h | 2 + tools/include/linux/rosebush.h | 1 + tools/include/linux/spinlock.h | 2 + tools/include/linux/stddef.h | 3 + tools/testing/radix-tree/.gitignore | 1 + tools/testing/radix-tree/Makefile | 6 +- tools/testing/radix-tree/kunit/test.h | 20 + tools/testing/radix-tree/linux/kernel.h | 2 + tools/testing/radix-tree/linux/vmalloc.h | 14 + tools/testing/radix-tree/rosebush.c | 36 ++ 20 files changed, 1135 insertions(+), 100 deletions(-) create mode 100644 Documentation/core-api/rosebush.rst create mode 100644 include/linux/rosebush.h create mode 100644 lib/rosebush.c create mode 100644 lib/test_rosebush.c create mode 100644 tools/include/linux/rosebush.h create mode 100644 tools/include/linux/stddef.h create mode 100644 tools/testing/radix-tree/kunit/test.h create mode 100644 tools/testing/radix-tree/linux/vmalloc.h create mode 100644 tools/testing/radix-tree/rosebush.c -- 2.43.0
