On Thu, Feb 02, 2017 at 09:15:26AM -0500, Waiman Long wrote: > v2->v3: > - Keep the original v1 patches but move patch 3 of v2 in front so > as to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC is on. > > v1->v2: > - Pack lockup and break_lock into a single 4-byte slot so as not > to in increase spinlock size when GENERIC_LOCKBREAK is > on. Hopefully that will be enough to fix a frame size too large > warning in 0-day build. > - Add a new patch to disable GENERIC_LOCKBREAK when DEBUG_LOCK_ALLOC > is on. > > The current debug spinlock implementation is a TATAS unfair lock. This > can occasionally lead to system lockup with a debug kernel because > of the unfairness of the lock rather than inherent locking problem. > > This patch set changes the debug spinlock implementation to a > mostly fair spinlock based on the MCS lock similar to what is done > in qspinlock. It also includes a patch that disable GENERIC_LOCKBREAK > when DEBUG_LOCK_ALLOC is on.
An alternative is to just delete the thing entirely.. Ingo, much of what this thing does seems to be superseded by both lockdep and a reliable NMI watchdog. Is there still value in spinlock_debug?
