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. Waiman Long (2): fs: Add a pool of extra fs->pwd references to fs_struct audit: Use the new {get,put}_fs_pwd_pool() APIs to get/put pwd references fs/fs_struct.c | 26 +++++++++++++++++++++----- fs/namespace.c | 8 ++++++++ include/linux/fs_struct.h | 28 +++++++++++++++++++++++++++- kernel/auditsc.c | 7 +++++-- 4 files changed, 61 insertions(+), 8 deletions(-) -- 2.53.0
