| Message ID | 20230502133847.14570-1-mkoutny@suse.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Rework locking when rendering mountinfo cgroup paths | expand |
On Tue, May 02, 2023 at 03:38:44PM +0200, Michal Koutný wrote: > Idea for these modification came up when css_set_lock seemed unneeded in > cgroup_show_path. > It's a delicate change, so the deciding factor was when cgroup_show_path popped > up also in some profiles of frequent mountinfo readers. > The idea is to trade the exclusive css_set_lock for the shared > namespace_sem when rendering cgroup paths. Details are described more in I have no issue with the cgroup specific part of relying on namespace_sem but kernel/cgroup/ has no business of being aware of namespace semaphore in any way. Leave a comment to clarify what you're doing but we're not going to sprinkle namespace_sem references - even if only for the sake of lockdep - into other subsystems.
Idea for these modification came up when css_set_lock seemed unneeded in cgroup_show_path. It's a delicate change, so the deciding factor was when cgroup_show_path popped up also in some profiles of frequent mountinfo readers. The idea is to trade the exclusive css_set_lock for the shared namespace_sem when rendering cgroup paths. Details are described more in individual commits. Michal Koutný (3): cgroup: Drop unused function for cgroup_path cgroup: Rely on namespace_sem in current_cgns_cgroup_from_root explicitly cgroup: Do not take css_set_lock in cgroup_show_path fs/namespace.c | 5 +++- include/linux/mount.h | 4 +++ kernel/cgroup/cgroup.c | 58 ++++++++---------------------------------- 3 files changed, 18 insertions(+), 49 deletions(-)