This is a small patch series that's been in the bcachefs tree for awhile. In the buffered read path, we look up a page in the page cache, then copy from that page in a loop - i.e. mixing the data copies in between looking up each individual page. When we're doing large reads from the page cache, this is some pretty major overhead. This just reworks generic_file_buffered_read() to use find_get_pages_contig() and work on an array of pages. It's a pretty significant performance improvement for large buffered reads, and doesn't regress performance on single page reads. As a bonus, generic_file_buffered_read() gets broken up into multiple functions that are _somewhat_ easier to follow. Kent Overstreet (2): fs: Break generic_file_buffered_read up into multiple functions fs: generic_file_buffered_read() now uses find_get_pages_contig mm/filemap.c | 486 +++++++++++++++++++++++++++++---------------------- 1 file changed, 273 insertions(+), 213 deletions(-) -- 2.27.0
