From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f173.google.com (mail-pf0-f173.google.com [209.85.192.173]) by kanga.kvack.org (Postfix) with ESMTP id 6CEB16B007E for ; Thu, 31 Mar 2016 04:45:17 -0400 (EDT) Received: by mail-pf0-f173.google.com with SMTP id x3so64612562pfb.1 for ; Thu, 31 Mar 2016 01:45:17 -0700 (PDT) Received: from mail-pf0-x22c.google.com (mail-pf0-x22c.google.com. [2607:f8b0:400e:c00::22c]) by mx.google.com with ESMTPS id ao8si12658326pad.241.2016.03.31.01.45.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Mar 2016 01:45:16 -0700 (PDT) Received: by mail-pf0-x22c.google.com with SMTP id n5so64607257pfn.2 for ; Thu, 31 Mar 2016 01:45:16 -0700 (PDT) Date: Thu, 31 Mar 2016 17:46:39 +0900 From: Sergey Senozhatsky Subject: Re: [PATCH] zsmalloc: use workqueue to destroy pool in zpool callback Message-ID: <20160331084639.GB3343@swordfish> References: <1459288977-25562-1-git-send-email-yuzhao@google.com> <20160329235950.GA19927@bbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160329235950.GA19927@bbox> Sender: owner-linux-mm@kvack.org List-ID: To: Yu Zhao Cc: Minchan Kim , Nitin Gupta , Sergey Senozhatsky , linux-mm@kvack.org, Dan Streetman , Seth Jennings , Sergey Senozhatsky , Andrew Morton , linux-kernel@vger.kernel.org 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 > [] mutex_lock+0x1b/0x2f > [] kmem_cache_destroy+0x50/0x130 > [] zs_destroy_pool+0x85/0xe0 > [] zs_zpool_destroy+0xe/0x10 > [] zpool_destroy_pool+0x54/0x70 > [] __zswap_pool_release+0x62/0x90 > [] rcu_process_callbacks+0x22e/0x640 > [] ? run_timer_softirq+0x3e/0x280 > [] __do_softirq+0xcb/0x250 > [] irq_exit+0x9c/0xb0 > [] smp_apic_timer_interrupt+0x6a/0x80 > [] 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@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org