Wang Yugui has a workload which would be improved by using large folios. Until now, we've only created large folios in the readahead path, but this workload writes without reading. The decision of what size folio to create is based purely on the size of the write() call (unlike readahead where we keep history and can choose to create larger folios based on that history even if individual reads are small). The third patch looks like it's an optional extra but is actually needed for the first two patches to work in the write path, otherwise it limits the length that iomap_get_folio() sees to PAGE_SIZE. Matthew Wilcox (Oracle) (3): filemap: Allow __filemap_get_folio to allocate large folios iomap: Create large folios in the buffered write path iomap: Copy larger chunks from userspace fs/gfs2/bmap.c | 2 +- fs/iomap/buffered-io.c | 32 ++++++++++++++++++------------ include/linux/iomap.h | 2 +- include/linux/pagemap.h | 29 ++++++++++++++++++++++++--- mm/filemap.c | 44 ++++++++++++++++++++++++++++------------- mm/folio-compat.c | 2 +- mm/readahead.c | 13 ------------ 7 files changed, 78 insertions(+), 46 deletions(-) -- 2.39.2
