On (03/30/16 08:59), Minchan Kim wrote: > On Tue, Mar 29, 2016 at 03:02:57PM -0700, Yu Zhao wrote: > > zs_destroy_pool() might sleep so it shouldn't be used in zpool > > destroy callback which can be invoked in softirq context when > > zsmalloc is configured to work with zswap. > > I think it's a limitation of zswap design, not zsmalloc. > Could you handle it in zswap? agree. hm, looking at this backtrace > [<ffffffffaea0224b>] mutex_lock+0x1b/0x2f > [<ffffffffaebca4f0>] kmem_cache_destroy+0x50/0x130 > [<ffffffffaec10405>] zs_destroy_pool+0x85/0xe0 > [<ffffffffaec1046e>] zs_zpool_destroy+0xe/0x10 > [<ffffffffaec101a4>] zpool_destroy_pool+0x54/0x70 > [<ffffffffaebedac2>] __zswap_pool_release+0x62/0x90 > [<ffffffffaeb1037e>] rcu_process_callbacks+0x22e/0x640 > [<ffffffffaeb15a3e>] ? run_timer_softirq+0x3e/0x280 > [<ffffffffaeabe13b>] __do_softirq+0xcb/0x250 > [<ffffffffaeabe4dc>] irq_exit+0x9c/0xb0 > [<ffffffffaea03e7a>] smp_apic_timer_interrupt+0x6a/0x80 > [<ffffffffaf0a394f>] apic_timer_interrupt+0x7f/0x90 it also can hit the following path rcu_process_callbacks() __zswap_pool_release() zswap_pool_destroy() zswap_cpu_comp_destroy() cpu_notifier_register_begin() mutex_lock(&cpu_add_remove_lock); <<< can't it? -ss -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>