Hello, This patchset changes cgroup inode number and id management to be in sync with kernfs. Currently cgroup inode is managed by kernfs while cgroup id is allocated by its own idr. And kernfs/cgroup file handle uses inode and generation numbers. So I added generation number to cgroup and pass the numbers to kernfs.
The background of this work is that I want to add cgroup sampling feature in the perf event subsystem. As Tejun mentioned that using cgroup id is not enough and it'd better using file handle instead. But getting file handle in perf NMI handler is not possible so I want to get the info from a cgroup node. The first patch added generation number to cgroup and the second patch allows kernfs node created with external generation and inode numbers. The patches are based on the for-next branch in Tejun's cgroup tree. Tested with tools/testing/selftests/cgroup/test_stress.sh. Thanks Namhyung Namhyung Kim (2): cgroup: Add generation number with cgroup id kernfs: Allow creation with external gen + ino numbers arch/x86/kernel/cpu/resctrl/rdtgroup.c | 4 +- fs/kernfs/dir.c | 63 +++++++++++++++++------ fs/kernfs/file.c | 9 ++-- fs/kernfs/kernfs-internal.h | 5 ++ fs/sysfs/file.c | 2 +- include/linux/cgroup-defs.h | 12 ++++- include/linux/kernfs.h | 25 ++++++--- kernel/cgroup/cgroup.c | 70 +++++++++++++++++++------- 8 files changed, 143 insertions(+), 47 deletions(-) -- 2.23.0.700.g56cf767bdb-goog
