On (04/25/16 15:18), Yu Zhao wrote:
> On Mon, Apr 25, 2016 at 05:20:10PM -0400, Dan Streetman wrote:
> > Add a work_struct to struct zpool, and change zpool_destroy_pool to
> > defer calling the pool implementation destroy.
> >
> > The zsmalloc pool destroy function, which is one of the zpool
> > implementations, may sleep during destruction of the pool. However
> > zswap, which uses zpool, may call zpool_destroy_pool from atomic
> > context. So we need to defer the call to the zpool implementation
> > to destroy the pool.
> >
> > This is essentially the same as Yu Zhao's proposed patch to zsmalloc,
> > but moved to zpool.
>
> Thanks, Dan. Sergey also mentioned another call path that triggers the
> same problem (BUG: scheduling while atomic):
> rcu_process_callbacks()
> __zswap_pool_release()
> zswap_pool_destroy()
> zswap_cpu_comp_destroy()
> cpu_notifier_register_begin()
> mutex_lock(&cpu_add_remove_lock);
> So I was thinking zswap_pool_destroy() might be done in workqueue in zswap.c.
> This way we fix both call paths.
right, I'm not sure the patch addressed all of the issues.
-ss
