Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758280Ab1DYKe7 (ORCPT ); Mon, 25 Apr 2011 06:34:59 -0400 Received: from legolas.restena.lu ([158.64.1.34]:41884 "EHLO legolas.restena.lu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758151Ab1DYKe6 convert rfc822-to-8bit (ORCPT ); Mon, 25 Apr 2011 06:34:58 -0400 Date: Mon, 25 Apr 2011 12:34:44 +0200 From: Bruno =?UTF-8?B?UHLDqW1vbnQ=?= To: Pekka Enberg Cc: Mike Frysinger , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Catalin Marinas Subject: Re: 2.6.39-rc4+: Kernel leaking memory during FS scanning, regression? Message-ID: <20110425123444.639aad34@neptune.home> In-Reply-To: References: <20110424202158.45578f31@neptune.home> <20110424235928.71af51e0@neptune.home> <20110425114429.266A.A69D9226@jp.fujitsu.com> <20110425111705.786ef0c5@neptune.home> X-Mailer: Claws Mail 3.7.8 (GTK+ 2.22.1; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7938 Lines: 160 On Mon, 25 April 2011 Pekka Enberg wrote: > On Mon, Apr 25, 2011 at 12:17 PM, Bruno Prémont > wrote: > > On Mon, 25 April 2011 Mike Frysinger wrote: > >> On Sun, Apr 24, 2011 at 22:42, KOSAKI Motohiro wrote: > >> >> On Sun, 24 April 2011 Bruno Prémont wrote: > >> >> > On an older system I've been running Gentoo's revdep-rebuild to check > >> >> > for system linking/*.la consistency and after doing most of the work the > >> >> > system starved more or less, just complaining about stuck tasks now and > >> >> > then. > >> >> > Memory usage graph as seen from userspace showed sudden quick increase of > >> >> > memory usage though only a very few MB were swapped out (c.f. attached RRD > >> >> > graph). > >> >> > >> >> Seems I've hit it once again (though detected before system was fully > >> >> stalled by trying to reclaim memory without success). > >> >> > >> >> This time it was during simple compiling... > >> >> Gathered info below: > >> >> > >> >> /proc/meminfo: > >> >> MemTotal:         480660 kB > >> >> MemFree:           64948 kB > >> >> Buffers:           10304 kB > >> >> Cached:             6924 kB > >> >> SwapCached:         4220 kB > >> >> Active:            11100 kB > >> >> Inactive:          15732 kB > >> >> Active(anon):       4732 kB > >> >> Inactive(anon):     4876 kB > >> >> Active(file):       6368 kB > >> >> Inactive(file):    10856 kB > >> >> Unevictable:          32 kB > >> >> Mlocked:              32 kB > >> >> SwapTotal:        524284 kB > >> >> SwapFree:         456432 kB > >> >> Dirty:                80 kB > >> >> Writeback:             0 kB > >> >> AnonPages:          6268 kB > >> >> Mapped:             2604 kB > >> >> Shmem:                 4 kB > >> >> Slab:             250632 kB > >> >> SReclaimable:      51144 kB > >> >> SUnreclaim:       199488 kB   <--- look big as well... > >> >> KernelStack:      131032 kB   <--- what??? > >> > > >> > KernelStack is used 8K bytes per thread. then, your system should have > >> > 16000 threads. but your ps only showed about 80 processes. > >> > Hmm... stack leak? > >> > >> i might have a similar report for 2.6.39-rc4 (seems to be working fine > >> in 2.6.38.4), but for embedded Blackfin systems running gdbserver > >> processes over and over (so lots of short lived forks) > >> > >> i wonder if you have a lot of zombies or otherwise unclaimed resources > >> ?  does `ps aux` show anything unusual ? > > > > I've not seen anything special (no big amount of threads behind my about 80 > > processes, even after kernel oom-killed nearly all processes the hogged > > memory has not been freed. And no, there are no zombies around). > > > > Here it seems to happened when I run 2 intensive tasks in parallel, e.g. > > (re)emerging gimp and running revdep-rebuild -pi in another terminal. > > This produces a fork rate of about 100-300 per second. > > > > Suddenly kmalloc-128 slabs stop being freed and things degrade. > > > > Trying to trace some of the kmalloc-128 slab allocations I end up seeing > > lots of allocations like this: > > > > [ 1338.554429] TRACE kmalloc-128 alloc 0xc294ff00 inuse=30 fp=0xc294ff00 > > [ 1338.554434] Pid: 1573, comm: collectd Tainted: G        W   2.6.39-rc4-jupiter-00187-g686c4cb #1 > > [ 1338.554437] Call Trace: > > [ 1338.554442]  [] trace+0x57/0xa0 > > [ 1338.554447]  [] alloc_debug_processing+0xf3/0x140 > > [ 1338.554452]  [] T.999+0x172/0x1a0 > > [ 1338.554455]  [] ? get_empty_filp+0x58/0xc0 > > [ 1338.554459]  [] ? get_empty_filp+0x58/0xc0 > > [ 1338.554464]  [] kmem_cache_alloc+0xb2/0x100 > > [ 1338.554468]  [] ? path_put+0x15/0x20 > > [ 1338.554472]  [] ? get_empty_filp+0x58/0xc0 > > [ 1338.554476]  [] get_empty_filp+0x58/0xc0 > > [ 1338.554481]  [] path_openat+0x1f/0x320 > > [ 1338.554485]  [] ? __access_remote_vm+0x19e/0x1d0 > > [ 1338.554490]  [] do_filp_open+0x30/0x80 > > [ 1338.554495]  [] ? kmem_cache_alloc+0x90/0x100 > > [ 1338.554500]  [] ? getname_flags+0x28/0xe0 > > [ 1338.554505]  [] ? alloc_fd+0x62/0xe0 > > [ 1338.554509]  [] ? getname_flags+0x61/0xe0 > > [ 1338.554514]  [] do_sys_open+0xed/0x1e0 > > [ 1338.554519]  [] sys_open+0x29/0x40 > > [ 1338.554524]  [] sysenter_do_call+0x12/0x26 > > [ 1338.556764] TRACE kmalloc-128 alloc 0xc294ff80 inuse=31 fp=0xc294ff80 > > [ 1338.556774] Pid: 1332, comm: bash Tainted: G        W   2.6.39-rc4-jupiter-00187-g686c4cb #1 > > [ 1338.556779] Call Trace: > > [ 1338.556794]  [] trace+0x57/0xa0 > > [ 1338.556802]  [] alloc_debug_processing+0xf3/0x140 > > [ 1338.556807]  [] T.999+0x172/0x1a0 > > [ 1338.556812]  [] ? get_empty_filp+0x58/0xc0 > > [ 1338.556817]  [] ? get_empty_filp+0x58/0xc0 > > [ 1338.556821]  [] kmem_cache_alloc+0xb2/0x100 > > [ 1338.556826]  [] ? get_empty_filp+0x58/0xc0 > > [ 1338.556830]  [] get_empty_filp+0x58/0xc0 > > [ 1338.556841]  [] ? tty_ldisc_deref+0x8/0x10 > > [ 1338.556849]  [] path_openat+0x1f/0x320 > > [ 1338.556857]  [] ? fbcon_cursor+0xfe/0x180 > > [ 1338.556863]  [] do_filp_open+0x30/0x80 > > [ 1338.556868]  [] ? kmem_cache_alloc+0x90/0x100 > > [ 1338.556873]  [] ? do_vfs_ioctl+0x7e/0x580 > > [ 1338.556878]  [] ? getname_flags+0x28/0xe0 > > [ 1338.556886]  [] ? alloc_fd+0x62/0xe0 > > [ 1338.556891]  [] ? getname_flags+0x61/0xe0 > > [ 1338.556898]  [] do_sys_open+0xed/0x1e0 > > [ 1338.556903]  [] sys_open+0x29/0x40 > > [ 1338.556913]  [] sysenter_do_call+0x12/0x26 > > > > Collectd is system monitoring daemon that counts processes, memory > > usage an much more, reading lots of files under /proc every 10 > > seconds. > > Maybe it opens a process related file at a racy moment and thus > > prevents the 128 slabs and kernel stacks from being released? > > > > Replaying the scenario I'm at: > > Slab:              43112 kB > > SReclaimable:      25396 kB > > SUnreclaim:        17716 kB > > KernelStack:       16432 kB > > PageTables:         1320 kB > > > > with > > kmalloc-256           55     64    256   16    1 : tunables    0    0    0 : slabdata      4      4      0 > > kmalloc-128        66656  66656    128   32    1 : tunables    0    0    0 : slabdata   2083   2083      0 > > kmalloc-64          3902   3904     64   64    1 : tunables    0    0    0 : slabdata     61     61      0 > > > > (and compiling process tree now SIGSTOPped in order to have system > > not starve immediately so I can look around for information) > > > > If I resume one of the compiling process trees both KernelStack and > > slab (kmalloc-128) usage increase quite quickly (and seems to never > > get down anymore) - probably at same rate as processes get born (no > > matter when they end). > > Looks like it might be a leak in VFS. You could try kmemleak to narrow > it down some more. See Documentation/kmemleak.txt for details. Hm, seems not to be willing to let me run kmemleak... each time I put on my load scenario I get "BUG: unable to handle kernel " on console as a last breath from the system. (the rest of the trace never shows up) Going to try harder to get at least a complete trace... Bruno > Pekka -- 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/