git: kernel - Improve concurrency in devfs VOPs

Matthew Dillon dillon at
Wed Oct 18 09:49:26 PDT 2017

commit 845bd036cbda57cad61596e264373e0e8461a760
Author: Matthew Dillon <dillon at>
Date:   Tue Oct 17 23:42:43 2017 -0700

    kernel - Improve concurrency in devfs VOPs
    * Use LK_SHARED instead of LK_EXCLUSIVE whenever possible.  This
      significantly reduces lock congestion for getattr(), read(),
      and readlink().
    * Check the new D_QUICK flag and, if set, devfs can avoid lock
      congestion for open() and close() on devices (e.g. such as on
      /dev/null, /dev/urandom, etc).

Summary of changes:
 sys/vfs/devfs/devfs_core.c  |  4 ++-
 sys/vfs/devfs/devfs_vnops.c | 74 ++++++++++++++++++++++++++++++++++++---------
 2 files changed, 62 insertions(+), 16 deletions(-)

DragonFly BSD source repository

More information about the Commits mailing list