RFC: [PATCH 0/6] lustre: Improve locking in lu_object.s

From: NeilBrown
Date: Thu May 10 2018 - 20:40:46 EST

This is a followup to the patches that James recently posted
which addressed some locking issues in lu_object.c.
I said at the time that I thought the locking could be
improved further. Here is the result of that thought.

The lu_keys_guard lock is now gone, replaced by a spin lock, an rwsem,
and some lockless code.
The lu_context_exit() function, which appears to have been a
performance problem at one point, is now completely lockless.

This is an RFC at this stage: I haven't included Greg on the email and
don't expect this to go upstream without some review - and maybe even
some testing.



NeilBrown (6):
staging: lustre: make key_set_version an atomic_t
staging: lustre: use an rwsem instead of lu_key_initing_cnt.
staging: lustre: remove locking from lu_context_exit()
staging: lustre: use wait_event_var() in lu_context_key_degister()
staging: lustre: remove lock from key register/degister
staging: lustre: rename lu_keys_guard to lu_context_remembered_guard

drivers/staging/lustre/lustre/include/lu_object.h | 1
drivers/staging/lustre/lustre/obdclass/lu_object.c | 187 ++++++++------------
2 files changed, 78 insertions(+), 110 deletions(-)