On 3/5/26 4:46 PM, Christian Brauner wrote:
On Sat, Feb 28, 2026 at 01:27:55PM -0500, Waiman Long wrote:
v4:
- Add ack and review tags
- Simplify put_fs_pwd_pool() in patch 1 as suggested by Paul Moore
v3:
- https://lore.kernel.org/lkml/[email protected]/
When the audit subsystem is enabled, it can do a lot of get_fs_pwd()
calls to get references to fs->pwd and then releasing those references
back with path_put() later. That may cause a lot of spinlock contention
on a single pwd's dentry lock because of the constant changes to the
reference count when there are many processes on the same working
directory actively doing open/close system calls. This can cause
noticeable performance regresssion when compared with the case where
the audit subsystem is turned off especially on systems with a lot of
CPUs which is becoming more common these days.
This patch series aim to avoid this type of performance regression caused
by audit by adding a new set of fs_struct helpers to reduce unncessary
path_get() and path_put() calls and the audit code is modified to use
these new helpers.
Tbh, the open-coding everywhere is really not very tasteful and makes me
not want to do this at all. Ideally we'd have a better mechanism that
avoids all this new spaghetti in various codepaths.
In it's current form I don't find it palatable. I added a few cleanups
on top that make it at least somewhat ok.
Thanks for the cleanup patches. They all look good to me.
Reviewed-by: Waiman Long <[email protected]>
