Hi, Here's a very tardy proposal for enhancements to Jan's original[1] range lock using interval trees. Because at some point it would be awesome to switch mmap_sem from rwsem to range rwlock, I've focused on making it sharable and performance enhancements reducing the performance delta between this and conventional locks as much as possible -- details in patch 1.
The rest of the patches adds support for testing the new lock and actually makes use of it for lustre. It has passed quite a bit of artificial pounding and I believe/hope it is in shape to consider. Applies on top of v4.11-rc1. [1] https://lkml.org/lkml/2013/1/31/483 Thanks! Davidlohr Bueso (5): locking: Introduce range reader/writer lock locking/locktorture: Fix rwsem reader_delay locking/locktorture: Fix num reader/writer corner cases locking/locktorture: Support range rwlocks staging/lustre: Use generic range rwlock drivers/gpu/drm/Kconfig | 2 - drivers/gpu/drm/i915/Kconfig | 1 - drivers/staging/lustre/lustre/llite/Makefile | 2 +- drivers/staging/lustre/lustre/llite/file.c | 21 +- .../staging/lustre/lustre/llite/llite_internal.h | 4 +- drivers/staging/lustre/lustre/llite/llite_lib.c | 3 +- drivers/staging/lustre/lustre/llite/range_lock.c | 239 ----------- drivers/staging/lustre/lustre/llite/range_lock.h | 82 ---- include/linux/range_rwlock.h | 96 +++++ kernel/locking/Makefile | 2 +- kernel/locking/locktorture.c | 299 +++++++++---- kernel/locking/range_rwlock.c | 462 +++++++++++++++++++++ lib/Kconfig | 14 - lib/Kconfig.debug | 1 - lib/Makefile | 2 +- 15 files changed, 792 insertions(+), 438 deletions(-) delete mode 100644 drivers/staging/lustre/lustre/llite/range_lock.c delete mode 100644 drivers/staging/lustre/lustre/llite/range_lock.h create mode 100644 include/linux/range_rwlock.h create mode 100644 kernel/locking/range_rwlock.c -- 2.6.6
