From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: 2.6.39-rc4+: Kernel leaking memory during FS scanning, regression? Date: Wed, 27 Apr 2011 15:05:24 -0700 Message-ID: <20110427220524.GQ2135@linux.vnet.ibm.com> References: <20110426081904.0d2b1494@pluto.restena.lu> <20110426112756.GF4308@linux.vnet.ibm.com> <20110426183859.6ff6279b@neptune.home> <20110426190918.01660ccf@neptune.home> <20110427081501.5ba28155@pluto.restena.lu> <20110427204139.1b0ea23b@neptune.home> <4DB86BA4.8070401@draigBrady.com> <20110427213431.236c2a15@neptune.home> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Cc: =?iso-8859-1?Q?P=E1draig?= Brady , Thomas Gleixner , Linus Torvalds , Ingo Molnar , Peter Zijlstra , Mike Frysinger , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, "Paul E. McKenney" , Pekka Enberg To: Bruno =?iso-8859-1?Q?Pr=E9mont?= Return-path: Content-Disposition: inline In-Reply-To: <20110427213431.236c2a15@neptune.home> Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.vger.kernel.org On Wed, Apr 27, 2011 at 09:34:31PM +0200, Bruno Pr=E9mont wrote: > On Wed, 27 April 2011 P=E1draig Brady wrote: > > On 27/04/11 19:41, Bruno Pr=E9mont wrote: > > > On Wed, 27 April 2011 Bruno Pr=E9mont wrote: > > >> On Wed, 27 Apr 2011 00:28:37 +0200 (CEST) Thomas Gleixner wrote: > > >>> On Tue, 26 Apr 2011, Linus Torvalds wrote: > > >>>> On Tue, Apr 26, 2011 at 10:09 AM, Bruno Pr=E9mont wrote: > > >>>>> Just in case, /proc/$(pidof rcu_kthread)/status shows ~20k volu= ntary > > >>>>> context switches and exactly one non-voluntary one. > > >>>>> > > >>>>> In addition when rcu_kthread has stopped doing its work > > >>>>> `swapoff $(swapdevice)` seems to block forever (at least normal= shutdown > > >>>>> blocks on disabling swap device). > > >=20 > > > Apparently it's not swapoff but `umount -a -t tmpfs` that's getting > > > stuck here. Manual swapoff worked. Doesn't "umount" wait for an RCU grace period? If so, then your hang is just a consequence of RCU grace periods hanging, which in turn appears to be a consequence of rcu_kthread not being allowed to run. > > Anything to do with this? > > http://thread.gmane.org/gmane.linux.kernel.mm/60953/ >=20 > I don't think so, if it is, it is only loosely related. >=20 > From the trace you omitted to keep it's visible that it gets hit by > non-operating RCU kthread. Yep, makes sense! Thanx, Paul > Maybe existence of RCU barrier in this trace has some relation to > above thread but I don't see it at first glance. >=20 > [ 1714.960735] umount D 5a000040 5668 20331 20324 0x00000000 > [ 1714.960735] c3c99e5c 00000086 dd407900 5a000040 dd25a1a8 dd407900 d= d25a120 c3c99e0c > [ 1714.960735] c3c99e24 c10c1be2 c14d9f20 c3c99e5c c3c8c680 c3c8c680 0= 00000bb c3c99e24 > [ 1714.960735] c10c0b88 dd25a120 dd407900 ddfd4b40 c3c99e4c ddfc9d20 d= d402380 5a000010 > [ 1714.960735] Call Trace: > [ 1714.960735] [] ? check_object+0x92/0x210 > [ 1714.960735] [] ? init_object+0x38/0x70 > [ 1714.960735] [] ? check_object+0x92/0x210 > [ 1714.960735] [] schedule_timeout+0x16d/0x280 > [ 1714.960735] [] ? init_object+0x38/0x70 > [ 1714.960735] [] ? free_debug_processing+0x112/0x1f0 > [ 1714.960735] [] ? shmem_put_super+0x11/0x20 > [ 1714.960735] [] wait_for_common+0x9c/0x150 > [ 1714.960735] [] ? try_to_wake_up+0x170/0x170 > [ 1714.960735] [] wait_for_completion+0x12/0x20 > [ 1714.960735] [] rcu_barrier_sched+0x47/0x50 > ^^^^^^^^^^^^^^^^^ > [ 1714.960735] [] ? alloc_pid+0x370/0x370 > [ 1714.960735] [] deactivate_locked_super+0x3a/0x60 > [ 1714.960735] [] deactivate_super+0x48/0x70 > [ 1714.960735] [] mntput_no_expire+0x87/0xe0 > [ 1714.960735] [] sys_umount+0x60/0x320 > [ 1714.960735] [] ? remove_vma+0x3a/0x50 > [ 1714.960735] [] ? do_munmap+0x212/0x2f0 > [ 1714.960735] [] sys_oldumount+0x19/0x20 > [ 1714.960735] [] sysenter_do_call+0x12/0x26 >=20 > Bruno -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter= .ca/ Don't email: email@kvack.org