From: Shaohua Li <shli@xxxxxx> Hi, Currently blktrace isn't cgroup aware. blktrace prints out task name of current context, but the task of current context isn't always in the cgroup where the BIO comes from. We can't use task name to find out IO cgroup. For example, Writeback BIOs always comes from flusher thread but the BIOs are for different blk cgroups. Request could be requeued and dispatched from completely different tasks. MD/DM are another examples. This brings challenges if we want to use blktrace for performance tunning with cgroup enabled. This patchset try to fix the gap. We print out cgroup fhandle info in blktrace. Userspace can use open_by_handle_at() syscall to find the cgroup by fhandle. Or userspace can use name_to_handle_at() syscall to find fhandle for a cgroup and use a BPF program to filter out blktrace for a specific cgroup. The first 6 patches adds export operation handlers for kernfs, so userspace can use open_by_handle_at/name_to_handle_at to a kernfs file. Later patches make blktrace output cgroup info. Thanks, Shaohua V3 -> V4: - Address some issues pointed out by Tejun - Fix build errors with latest -next tree V2 -> V3: - Uses 32 bits inode number - Refresh to latest -next tree V1 -> V2: - Fix a bug in cgroup association - Fix build errors reported by 0day - Address some issues pointed out by Tejun Shaohua Li (12): kernfs: use idr instead of ida to manage inode number kernfs: implement i_generation kernfs: add an API to get kernfs node from inode number kernfs: don't set dentry->d_fsdata kernfs: introduce kernfs_node_id kernfs: add exportfs operations cgroup: export fhandle info for a cgroup blktrace: export cgroup info in trace block: always attach cgroup info into bio block: call __bio_free in bio_endio blktrace: add an option to allow displying cgroup path block: use standard blktrace API to output cgroup info for debug notes block/bfq-iosched.h | 13 +- block/bio-integrity.c | 1 + block/bio.c | 2 + block/blk-throttle.c | 13 +- block/cfq-iosched.c | 15 +-- fs/kernfs/dir.c | 111 ++++++++++++---- fs/kernfs/file.c | 10 +- fs/kernfs/inode.c | 9 +- fs/kernfs/kernfs-internal.h | 9 ++ fs/kernfs/mount.c | 94 ++++++++++++-- fs/kernfs/symlink.c | 6 +- include/linux/blk-cgroup.h | 3 + include/linux/blktrace_api.h | 13 +- include/linux/cgroup.h | 16 ++- include/linux/kernfs.h | 28 ++++- include/trace/events/writeback.h | 2 +- include/uapi/linux/blktrace_api.h | 3 + kernel/cgroup/cgroup.c | 15 ++- kernel/trace/blktrace.c | 259 ++++++++++++++++++++++++++------------ 19 files changed, 470 insertions(+), 152 deletions(-) -- 2.9.3
