Hi Sergey, On Mon, Apr 03, 2017 at 03:08:58PM +0900, Sergey Senozhatsky wrote: > Hello Minchan, > > On (04/03/17 14:17), Minchan Kim wrote: > > With this clean-up phase, I want to use zram's wrapper function > > to lock table access which is more consistent with other zram's > > functions. > > which reminds me of... > > there was a discussion a long time ago, -rt people absolutely > hate bit spin_locks and they suggested us to replace it with > normal spin_locks (and I promised to take a look at it, but > got interrupted and never really returned back to it). > > for !lockdep builds the impact is somewhat small; for lockdep > builds we increase the memory usage, but > > a) lockdep builds are debug builds by definition, no one runs lockdep > enabled kernels in production > > b) we have lockdep in zram now, which is nice
It's really one I want to have. > > c) spin_locks probably have better fairness guarantees In fact, it wouldn't be an imporant because zram's slot lock contention is not heavy. > > > what do you think? can we, in this patch set, also replce bit > spin_locks with a normal spin_lock? With changing only zram side from bit_spin_lock to spin_lock, it would be crippled. I mean zsmalloc should be changed, too and it's really hard. :(
