Thanks for review. On Fri, 26 Apr 2019 at 04:03, Peter Zijlstra <[email protected]> wrote: > > On Wed, Apr 24, 2019 at 06:19:30PM +0800, Yuyang Du wrote: > > In mark_lock_irq(), the following checks are performed: > > > > ---------------------------------- > > | -> | unsafe | read unsafe | > > |----------------------------------| > > | safe | F B | F* B* | > > |----------------------------------| > > | read safe | F? B* | - | > > ---------------------------------- > > > > Where: > > F: check_usage_forwards > > B: check_usage_backwards > > *: check enabled by STRICT_READ_CHECKS > > ?: check enabled by the !dir condition > > > > From checking point of view, the special F? case does not make sense, > > whereas it perhaps is made for peroformance concern. As later patch will > > address this issue, remove this exception, which makes the checks > > consistent later. > > > > With STRICT_READ_CHECKS = 1 which is default, there is no functional > > change. > > Oh man.. thinking required and it is way late.. anyway this whole read > stuff made me remember we had a patch set on readlocks last year. > > https://lkml.kernel.org/r/[email protected] > > I remember reviewing that a few times and then it dropped on the floor, > probably because Spectre crap or something sucked up all my time again :/ > > Sorry Boqun!
Oh man, I thought about the read-write lock stuff, but I didn't know Boqun's patch. Let me hurt my brain looking at that patch.
