One of the primary uses for NV-DIMMs is to expose them as a block device and use a filesystem to store files on the NV-DIMM. While that works, it currently wastes memory and CPU time buffering the files in the page cache. We have support in ext2 for bypassing the page cache, but it has some races which are unfixable in the current design. This series of patches rewrite the underlying support, and add support for direct access to ext4.
This iteration of the patchset rebases to Linus' 3.14-rc7 (plus Kirill's patches in linux-next http://marc.info/?l=linux-mm&m=139206489208546&w=2) and fixes several bugs: - Initialise cow_page in do_page_mkwrite() (Matthew Wilcox) - Clear new or unwritten blocks in page fault handler (Matthew Wilcox) - Only call get_block when necessary (Matthew Wilcox) - Reword Kconfig options (Matthew Wilcox / Vishal Verma) - Fix a race between page fault and truncate (Matthew Wilcox) - Fix a race between fault-for-read and fault-for-write (Matthew Wilcox) - Zero the correct bytes in dax_new_buf() (Toshi Kani) - Add DIO_LOCKING to an invocation of dax_do_io in ext4 (Ross Zwisler) Relative to the last patchset, I folded the 'Add reporting of major faults' patch into the patch that adds the DAX page fault handler. The v6 patchset had seven additional xfstests failures. This patchset now passes approximately as many xfstests as ext4 does on a ramdisk. Matthew Wilcox (21): Fix XIP fault vs truncate race Allow page fault handlers to perform the COW axonram: Fix bug in direct_access Change direct_access calling convention Introduce IS_DAX(inode) Replace XIP read and write with DAX I/O Replace the XIP page fault handler with the DAX page fault handler Replace xip_truncate_page with dax_truncate_page Remove mm/filemap_xip.c Remove get_xip_mem Replace ext2_clear_xip_target with dax_clear_blocks ext2: Remove ext2_xip_verify_sb() ext2: Remove ext2_use_xip ext2: Remove xip.c and xip.h Remove CONFIG_EXT2_FS_XIP and rename CONFIG_FS_XIP to CONFIG_FS_DAX ext2: Remove ext2_aops_xip Get rid of most mentions of XIP in ext2 xip: Add xip_zero_page_range ext4: Make ext4_block_zero_page_range static ext4: Fix typos brd: Rename XIP to DAX Ross Zwisler (1): ext4: Add DAX functionality Documentation/filesystems/Locking | 3 - Documentation/filesystems/dax.txt | 84 ++++++ Documentation/filesystems/ext4.txt | 2 + Documentation/filesystems/xip.txt | 68 ----- arch/powerpc/sysdev/axonram.c | 8 +- drivers/block/Kconfig | 13 +- drivers/block/brd.c | 22 +- drivers/s390/block/dcssblk.c | 19 +- fs/Kconfig | 21 +- fs/Makefile | 1 + fs/dax.c | 509 +++++++++++++++++++++++++++++++++++++ fs/exofs/inode.c | 1 - fs/ext2/Kconfig | 11 - fs/ext2/Makefile | 1 - fs/ext2/ext2.h | 9 +- fs/ext2/file.c | 45 +++- fs/ext2/inode.c | 37 +-- fs/ext2/namei.c | 13 +- fs/ext2/super.c | 48 ++-- fs/ext2/xip.c | 91 ------- fs/ext2/xip.h | 26 -- fs/ext4/ext4.h | 8 +- fs/ext4/file.c | 53 +++- fs/ext4/indirect.c | 19 +- fs/ext4/inode.c | 94 ++++--- fs/ext4/namei.c | 10 +- fs/ext4/super.c | 39 ++- fs/open.c | 5 +- include/linux/blkdev.h | 4 +- include/linux/fs.h | 49 +++- include/linux/mm.h | 2 + mm/Makefile | 1 - mm/fadvise.c | 6 +- mm/filemap.c | 6 +- mm/filemap_xip.c | 483 ----------------------------------- mm/madvise.c | 2 +- mm/memory.c | 45 +++- 37 files changed, 984 insertions(+), 874 deletions(-) create mode 100644 Documentation/filesystems/dax.txt delete mode 100644 Documentation/filesystems/xip.txt create mode 100644 fs/dax.c delete mode 100644 fs/ext2/xip.c delete mode 100644 fs/ext2/xip.h delete mode 100644 mm/filemap_xip.c -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
