Hi everyone, This is a followup to the patch series I sent out earlier [1] containing the middle two points: 1. always associate a bio with a blkg 2. remove the extra css ref held by bios and utilize the blkg ref The major difference with v2 is that error handling on blkg creation and association failure is handled more gracefully. Rather than having the complex logic to fallback to root, failures walk up the blkg tree. This seems more natural and less prone to error with the many possible failure scenarios. Additionally, there are fixes for kbuild errors and some key details overlooked by me in the first series that were pointed out in review. Modified from the first patchset: First, both blk-throttle and blk-iolatency rely on blkg association to enable their policies. Rather than each policy (and future policies) implement this logic independently, this consolidates it such that all bios are tagged with a blkg. Second, with the addition of always having a blkg reference, the blkcg can now be referenced through it rather than maintaining an additional pointer and reference. So let's clean this up. [1] https://lore.kernel.org/lkml/20180831015356.69796-1-dennisszhou@xxxxxxxxx/T This patchset contains the following 12 patches: 0001-blkcg-fix-ref-count-issue-with-bio_blkcg-using-task_.patch 0002-blkcg-update-blkg_lookup_create-to-do-locking.patch 0003-blkcg-convert-blkg_lookup_create-to-find-closest-blk.patch 0004-blkcg-always-associate-a-bio-with-a-blkg.patch 0005-blkcg-consolidate-bio_issue_init-to-be-a-part-of-cor.patch 0006-blkcg-associate-a-blkg-for-pages-being-evicted-by-sw.patch 0007-blkcg-associate-writeback-bios-with-a-blkg.patch 0008-blkcg-remove-bio-bi_css-and-instead-use-bio-bi_blkg.patch 0009-blkcg-remove-additional-reference-to-the-css.patch 0010-blkcg-cleanup-and-make-blk_get_rl-use-blkg_lookup_cr.patch 0011-blkcg-change-blkg-reference-counting-to-use-percpu_r.patch 0012-blkcg-rename-blkg_try_get-to-blkg_tryget.patch This patchset is on top of axboe#for-next 9c8f7b6493d9, a merge commit from merging back axboe#for-linus. diffstats below: Dennis Zhou (Facebook) (12): blkcg: fix ref count issue with bio_blkcg using task_css blkcg: update blkg_lookup_create to do locking blkcg: convert blkg_lookup_create to find closest blkg blkcg: always associate a bio with a blkg blkcg: consolidate bio_issue_init to be a part of core blkcg: associate a blkg for pages being evicted by swap blkcg: associate writeback bios with a blkg blkcg: remove bio->bi_css and instead use bio->bi_blkg blkcg: remove additional reference to the css blkcg: cleanup and make blk_get_rl use blkg_lookup_create blkcg: change blkg reference counting to use percpu_ref blkcg: rename blkg_try_get to blkg_tryget Documentation/admin-guide/cgroup-v2.rst | 8 +- block/bfq-cgroup.c | 4 +- block/bfq-iosched.c | 2 +- block/bio.c | 153 ++++++++++++++++-------- block/blk-cgroup.c | 120 +++++++++++++------ block/blk-iolatency.c | 26 +--- block/blk-throttle.c | 13 +- block/bounce.c | 4 +- block/cfq-iosched.c | 4 +- drivers/block/loop.c | 5 +- drivers/md/raid0.c | 2 +- fs/buffer.c | 10 +- fs/ext4/page-io.c | 2 +- include/linux/bio.h | 23 ++-- include/linux/blk-cgroup.h | 147 ++++++++++++++++------- include/linux/blk_types.h | 1 - include/linux/cgroup.h | 2 + include/linux/writeback.h | 5 +- kernel/cgroup/cgroup.c | 53 ++++++-- kernel/trace/blktrace.c | 4 +- mm/page_io.c | 2 +- 21 files changed, 380 insertions(+), 210 deletions(-) Thanks, Dennis
