Performing userfaultfd operations (like copy/move etc.) in critical section of mmap_lock (read-mode) causes significant contention on the lock when operations requiring the lock in write-mode are taking place concurrently. We can use per-vma locks instead to significantly reduce the contention issue. Changes since v1 [1]: - rebase patches on 'mm-unstable' branch [1] https://lore.kernel.org/all/20240126182647.2748949-1-lokeshgidra@xxxxxxxxxx/ Lokesh Gidra (3): userfaultfd: move userfaultfd_ctx struct to header file userfaultfd: protect mmap_changing with rw_sem in userfaulfd_ctx userfaultfd: use per-vma locks in userfaultfd operations fs/userfaultfd.c | 86 ++++--------- include/linux/userfaultfd_k.h | 75 ++++++++--- mm/userfaultfd.c | 229 ++++++++++++++++++++++------------ 3 files changed, 229 insertions(+), 161 deletions(-) -- 2.43.0.429.g432eaa2c6b-goog
