Page I/O allows us to read/write pages to storage without allocating any memory (in particular, it avoids allocating a BIO). This is nice for the purposes of swap and reduces overhead for fast storage devices. The downside is that it removes all batching from the I/O path, potentially sending dozens of commands for a large I/O instead of just one. This iteration of the Page I/O patchset has been tested with xfstests on ext4 on brd, and there are no unexpected failures. Changes since v1: - Rebased to 3.14-rc7 - Separate out the clean_buffers() refactoring into its own patch - Change the page_endio() interface to take an error code rather than a boolean 'success'. All of its callers prefer this (and my earlier patchset got this wrong in one caller). - Added kerneldoc to bdev_read_page() and bdev_write_page() - bdev_write_page() now does less on failure. Since its two customers (swap and mpage) want to do different things to the page flags on failure, let them. - Drop the virtio_blk patch, since I don't think it should be included Keith Busch (1): NVMe: Add support for rw_page Matthew Wilcox (5): Factor clean_buffers() out of __mpage_writepage() Factor page_endio() out of mpage_end_io() Add bdev_read_page() and bdev_write_page() swap: Use bdev_read_page() / bdev_write_page() brd: Add support for rw_page drivers/block/brd.c | 10 ++++ drivers/block/nvme-core.c | 129 +++++++++++++++++++++++++++++++++++++--------- fs/block_dev.c | 63 ++++++++++++++++++++++ fs/mpage.c | 84 +++++++++++++++--------------- include/linux/blkdev.h | 4 ++ include/linux/pagemap.h | 2 + mm/filemap.c | 25 +++++++++ mm/page_io.c | 23 ++++++++- 8 files changed, 273 insertions(+), 67 deletions(-) -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
