On Fri, Jun 01, 2018 at 04:09:54PM +0200, David Sterba wrote: > On Fri, May 25, 2018 at 11:45:48AM +0800, Ming Lei wrote: > > fs/btrfs/check-integrity.c | 6 +- > > fs/btrfs/compression.c | 8 +- > > fs/btrfs/disk-io.c | 3 +- > > fs/btrfs/extent_io.c | 14 ++- > > fs/btrfs/file-item.c | 4 +- > > fs/btrfs/inode.c | 12 ++- > > fs/btrfs/raid56.c | 5 +- > > For the btrfs bits, > Acked-by: David Sterba <dsterba@xxxxxxxx> > > but that's from the bio API user perspective only, I'll leave the design > and implementation questions to others. > > I've let the patchset through fstests, no problems. One thing that caught Thanks for your test! > my eye was use of the 'struct bvec_iter_all' in random functions. As > this structure is a compound of 2 others and is 40 bytes in size, I was > curious how this increased stack consumption. > > Measured with -fstack-usage before and after patch 22/33 "btrfs: conver to > bio_for_each_page_all2" > > -disk-io.c:btree_csum_one_bio 48 static > +disk-io.c:btree_csum_one_bio 80 static > -extent_io.c:end_bio_extent_buffer_writepage 56 static > +extent_io.c:end_bio_extent_buffer_writepage 80 static > -extent_io.c:end_bio_extent_readpage 176 dynamic,bounded > +extent_io.c:end_bio_extent_readpage 240 dynamic,bounded > -extent_io.c:end_bio_extent_writepage 56 static > +extent_io.c:end_bio_extent_writepage 120 static > -inode.c:btrfs_retry_endio 96 dynamic,bounded > +inode.c:btrfs_retry_endio 144 dynamic,bounded > -inode.c:btrfs_retry_endio_nocsum 72 dynamic,bounded > +inode.c:btrfs_retry_endio_nocsum 104 dynamic,bounded > -raid56.c:set_bio_pages_uptodate 8 static > +raid56.c:set_bio_pages_uptodate 40 static > > It's not that bad, but still quite a lot just to iterate a list of bios. I > think it's worth mentioning as it affects several other filesystems and > should be possibly optimized in the future. OK. We could decrease the affect by using a lightweight iterator for bio_for_each_page_all2(), will do it in V6. Thanks, Ming
