From: Michal Hocko <mhocko@suse.cz>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Christoph Lameter <cl@linux.com>,
Jesper Dangaard Brouer <brouer@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: mmotm: mm-slub-optimize-alloc-free-fastpath-by-removing-preemption-on-off.patch is causing preemptible splats
Date: Wed, 21 Jan 2015 14:23:08 +0100 [thread overview]
Message-ID: <20150121132308.GB23700@dhcp22.suse.cz> (raw)
Hi,
I am getting tons of splats like this:
[ 187.593291] BUG: using smp_processor_id() in preemptible [00000000] code: kworker/u4:1/24
[ 187.593293] caller is debug_smp_processor_id+0x17/0x19
[ 187.599127] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[ 187.601997] ffffffff8181786e ffff8800068a3d78 ffffffff8151a4b8 ffffffff81078e0e
[ 187.604373] 0000000000000000 ffff8800068a3da8 ffffffff81280ac0 ffff8800068acac8
[ 187.606619] 00000000000029b2 ffff880007401500 00000000000000d0 ffff8800068a3db8
[ 187.608869] Call Trace:
[ 187.609602] [<ffffffff8151a4b8>] dump_stack+0x4f/0x7c
[ 187.615881] [<ffffffff81078e0e>] ? down_trylock+0x2d/0x37
[ 187.617468] [<ffffffff81280ac0>] check_preemption_disabled+0xe7/0xf9
[ 187.619295] [<ffffffff81280ae9>] debug_smp_processor_id+0x17/0x19
[ 187.621055] [<ffffffff8113b2f6>] kmem_cache_alloc_trace+0x78/0x22e
[ 187.622854] [<ffffffff81088d36>] ? do_syslog+0xb2/0x452
[ 187.624376] [<ffffffff81088d36>] do_syslog+0xb2/0x452
[ 187.626030] [<ffffffff811675b4>] ? __fdget_pos+0x3d/0x43
[ 187.627557] [<ffffffff810745ac>] ? wait_woken+0x5d/0x5d
[ 187.629073] [<ffffffff811675b4>] ? __fdget_pos+0x3d/0x43
[ 187.630611] [<ffffffff811a787b>] kmsg_read+0x2d/0x54
[ 187.632069] [<ffffffff8119c4ff>] proc_reg_read+0x4a/0x6c
[ 187.633775] [<ffffffff8114e4d8>] vfs_read+0xa5/0x141
[ 187.635242] [<ffffffff8114ee35>] SyS_read+0x51/0x8f
[ 187.636666] [<ffffffff81522892>] system_call_fastpath+0x12/0x17
$ grep "BUG: using smp_processor_id" mmap.qcow_serial.log | wc -l
660
after few minutes of runtime when running the current mmotm tree
(https://git.kernel.org/cgit/linux/kernel/git/mhocko/mm.git/log/?h=since-3.18).
The warning seems to come from this_cpu_ptr which is using my_cpu_offset
which is
#define my_cpu_offset per_cpu_offset(smp_processor_id())
if CONFIG_DEBUG_PREEMPT
So it matches the following code in slab_alloc_node resp. slab_free:
do {
tid = this_cpu_read(s->cpu_slab->tid);
c = this_cpu_ptr(s->cpu_slab); <<< HERE
} while (IS_ENABLED(CONFIG_PREEMPT) && unlikely(tid != c->tid));
This is with:
CONFIG_PREEMPT=y
CONFIG_PREEMPT_COUNT=y
CONFIG_DEBUG_PREEMPT=y
I am not sure how to fix this but it sounds like this_cpu_ptr should
offer the same preempt expectations as other this_cpu_* functions.
--
Michal Hocko
SUSE Labs
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next reply other threads:[~2015-01-21 13:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-21 13:23 Michal Hocko [this message]
2015-01-21 14:06 ` Krzysztof Kozłowski
2015-01-21 14:11 ` Michal Hocko
2015-01-21 22:21 ` Andrew Morton
2015-01-22 1:51 ` Joonsoo Kim
2015-01-22 3:34 ` Andrew Morton
2015-01-22 5:14 ` Stephen Rothwell
2015-01-22 5:48 ` Andrew Morton
2015-01-22 16:14 ` Christoph Lameter
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