[PATCH v2 0/3] per-vma locks in userfaultfd

[Lokesh Gidra <lokeshgidra@google.com>]

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@google.com/

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