On Sat, 2020-12-19 at 11:20 +0100, Vitaly Wool wrote: > Hi Mike, > > On Sat, Dec 19, 2020 at 11:12 AM Mike Galbraith <efault@xxxxxx> wrote: > > > > (mailer partially munged formatting? resend) > > > > mm/zswap: fix zswap_frontswap_load() vs zsmalloc::map/unmap() might_sleep() splat > > > > zsmalloc map/unmap methods use preemption disabling bit spinlocks. Take the > > mutex outside of pool map/unmap methods in zswap_frontswap_load() as is done > > in zswap_frontswap_store(). > > oh wait... So is zsmalloc taking a spin lock in its map callback and > releasing it only in unmap? In this case, I would rather keep zswap as > is, mark zsmalloc as RT unsafe and have zsmalloc maintainer fix it. The kernel that generated that splat was NOT an RT kernel, it was plain master.today with a PREEMPT config. -Mike
