RE: [PATCH] zsmalloc: do not use bit_spin_lock

[Song Bao Hua (Barry Song)]

> I'm still not convinced. Will kmap what, src? At this point src might become just a bogus pointer. 

As long as the memory is still there, we can kmap it by its page struct. But if
it is not there anymore, we have no way.

> Why couldn't the object have been moved somewhere else (due to the compaction mechanism for instance)
> at the time DMA kicks in?

So zs_map_object() will guarantee the src won't be moved by holding those preemption-disabled lock?
If so, it seems we have to drop the MOVABLE gfp in zswap for zsmalloc case?

> 
> >
> > ~Vitaly
> 

Thanks
Barry