Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932721AbbFGAxM (ORCPT ); Sat, 6 Jun 2015 20:53:12 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:24204 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752663AbbFGAxC (ORCPT ); Sat, 6 Jun 2015 20:53:02 -0400 Message-ID: <55739536.5040509@oracle.com> Date: Sat, 06 Jun 2015 20:49:58 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Tejun Heo , axboe@kernel.dk CC: linux-kernel@vger.kernel.org, jack@suse.cz, hch@infradead.org, hannes@cmpxchg.org, linux-fsdevel@vger.kernel.org, vgoyal@redhat.com, lizefan@huawei.com, cgroups@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.cz, clm@fb.com, fengguang.wu@intel.com, david@fromorbit.com, gthelen@google.com, khlebnikov@yandex-team.ru Subject: Re: [PATCH 16/51] writeback: move backing_dev_info->wb_lock and ->worklist into bdi_writeback References: <1432329245-5844-1-git-send-email-tj@kernel.org> <1432329245-5844-17-git-send-email-tj@kernel.org> In-Reply-To: <1432329245-5844-17-git-send-email-tj@kernel.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Source-IP: userv0022.oracle.com [156.151.31.74] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4573 Lines: 89 On 05/22/2015 05:13 PM, Tejun Heo wrote: > Currently, a bdi (backing_dev_info) embeds single wb (bdi_writeback) > and the role of the separation is unclear. For cgroup support for > writeback IOs, a bdi will be updated to host multiple wb's where each > wb serves writeback IOs of a different cgroup on the bdi. To achieve > that, a wb should carry all states necessary for servicing writeback > IOs for a cgroup independently. > > This patch moves bdi->wb_lock and ->worklist into wb. > > * The lock protects bdi->worklist and bdi->wb.dwork scheduling. While > moving, rename it to wb->work_lock as wb->wb_lock is confusing. > Also, move wb->dwork downwards so that it's colocated with the new > ->work_lock and ->work_list fields. > > * bdi_writeback_workfn() -> wb_workfn() > bdi_wakeup_thread_delayed(bdi) -> wb_wakeup_delayed(wb) > bdi_wakeup_thread(bdi) -> wb_wakeup(wb) > bdi_queue_work(bdi, ...) -> wb_queue_work(wb, ...) > __bdi_start_writeback(bdi, ...) -> __wb_start_writeback(wb, ...) > get_next_work_item(bdi) -> get_next_work_item(wb) > > * bdi_wb_shutdown() is renamed to wb_shutdown() and now takes @wb. > The function contained parts which belong to the containing bdi > rather than the wb itself - testing cap_writeback_dirty and > bdi_remove_from_list() invocation. Those are moved to > bdi_unregister(). > > * bdi_wb_{init|exit}() are renamed to wb_{init|exit}(). > Initializations of the moved bdi->wb_lock and ->work_list are > relocated from bdi_init() to wb_init(). > > * As there's still only one bdi_writeback per backing_dev_info, all > uses of bdi->state are mechanically replaced with bdi->wb.state > introducing no behavior changes. > > Signed-off-by: Tejun Heo > Reviewed-by: Jan Kara > Cc: Jens Axboe > Cc: Wu Fengguang Hi Tejun, I'm now seeing: [619070.603554] WARNING: CPU: 10 PID: 8316 at lib/list_debug.c:56 __list_del_entry+0x104/0x1a0() [619070.604573] list_del corruption, ffff880540ad6fb8->prev is LIST_POISON2 (dead000000200200) [619070.605501] Modules linked in: [619070.606103] CPU: 10 PID: 8316 Comm: mount Not tainted 4.1.0-rc6-next-20150604-sasha-00039-g07bbbaf #2 268 [619070.607386] ffff8800c9aeb000 0000000061727ceb ffff8800c9387a38 ffffffffa3a02988 [619070.608791] 0000000000000000 ffff8800c9387ab8 ffff8800c9387a88 ffffffff9a1e5336 [619070.610029] ffff8802b6008680 ffffffff9bdae994 ffff8800c9387a68 ffffed0019270f53 [619070.610978] Call Trace: [619070.611357] dump_stack (lib/dump_stack.c:52) [619070.612019] warn_slowpath_common (kernel/panic.c:448) [619070.612666] ? __list_del_entry (lib/list_debug.c:54 (discriminator 1)) [619070.613435] warn_slowpath_fmt (kernel/panic.c:454) [619070.614102] ? warn_slowpath_common (kernel/panic.c:454) [619070.614900] ? lock_acquired (kernel/locking/lockdep.c:3890) [619070.615642] __list_del_entry (lib/list_debug.c:54 (discriminator 1)) [619070.616474] ? bdi_destroy (include/linux/rculist.h:131 mm/backing-dev.c:803 mm/backing-dev.c:812) [619070.617273] bdi_destroy (include/linux/rculist.h:132 mm/backing-dev.c:803 mm/backing-dev.c:812) [619070.618261] v9fs_session_close (include/linux/spinlock.h:312 fs/9p/v9fs.c:455) [619070.619121] v9fs_mount (fs/9p/vfs_super.c:200) [619070.619785] ? lockdep_init_map (kernel/locking/lockdep.c:3055) [619070.620507] mount_fs (fs/super.c:1109) [619070.621153] vfs_kern_mount (fs/namespace.c:948) [619070.621867] ? get_fs_type (fs/filesystems.c:278 (discriminator 2)) [619070.622412] do_mount (fs/namespace.c:2385 fs/namespace.c:2701) [619070.623035] ? copy_mount_string (fs/namespace.c:2634) [619070.623610] ? __might_fault (mm/memory.c:3775 (discriminator 1)) [619070.624389] ? __might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3773) [619070.625029] ? memdup_user (./arch/x86/include/asm/uaccess.h:718) [619070.625833] SyS_mount (fs/namespace.c:2894 fs/namespace.c:2869) [619070.626442] ? copy_mnt_ns (fs/namespace.c:2869) [619070.627131] ? __this_cpu_preempt_check (lib/smp_processor_id.c:63) [619070.628088] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2594 kernel/locking/lockdep.c:2636) [619070.629095] ? trace_hardirqs_on_thunk (arch/x86/lib/thunk_64.S:39) [619070.629847] system_call_fastpath (arch/x86/kernel/entry_64.S:195) Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/