On Thu, Apr 25, 2013 at 05:01:18PM +0800, Qiang Huang wrote: | This is revert of "sched-clear-pf-thread-bound-on-fallback-rq.patch" | (commit 0d939066acdcb in v3.4-rt),. | | Select_fallback_rq() can be easilly called during system boot, because | select_task_rq_fair() just return task_cpu(p) for bounded kernel threads, | which is 0 during system boot and not in tsk_cpus_allowed, so | select_fallback_rq() is called and PF_THREAD_BOUND is cleared. In my | box, 1/3 bounded kernel threads will clear that flag after boot. | | And it will cause problems, for example: | # for pid in `ps -e -o pid`; do taskset -p -c 0-15 $pid; done | this command will cause system hung. | | What's more, I don't see why we need to clear this flag any more, | because "cpu/rt: Rework cpu down for PREEMPT_RT" already remove the | optimization for PF_THREAD_BOUND on migrate_disable/enable. | | Signed-off-by: Qiang Huang <h.huangqiang@xxxxxxxxxx> | --- | kernel/sched/core.c | 6 ------ | 1 files changed, 0 insertions(+), 6 deletions(-) | | diff --git a/kernel/sched/core.c b/kernel/sched/core.c | index 751ec60..8db6e3b 100644 | --- a/kernel/sched/core.c | +++ b/kernel/sched/core.c | @@ -1327,12 +1327,6 @@ out: | } | } | | - /* | - * Clear PF_THREAD_BOUND, otherwise we wreckage | - * migrate_disable/enable. See optimization for | - * PF_THREAD_BOUND tasks there. | - */ | - p->flags &= ~PF_THREAD_BOUND; | return dest_cpu; | } | | -- 1.7.1 Sorry for the late post on this thread, but I just saw two occurrences of the Warning below (pretty close to the original report on this thread) on 3.8.11-rt8. As this patch solved/mitigated the issue on my 3.6-rt kernel, I am trying it on 3.8.11-rt8. The funny thing is that I was not running the cgroups_fj nor the shell script reproducer, just using the box to browse the web and listen to _good_ music. [19806.691965] ------------[ cut here ]------------ [19806.691979] WARNING: at /home/lclaudio/SANDBOX/v2-devel/kernel/workqueue.c:1575 worker_enter_idle+0xd8/0x130() [19806.691981] Hardware name: KQ260AA-AC4 a6540br [19806.691984] Modules linked in: vfat fat fuse nf_conntrack_netbios_ns nf_conntrack_broadcast ipt_MASQUERADE ip6table_mangle ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6 iptable_nat nf_nat_ipv4 nf_nat iptable_mangle nf_conntrack_ipv4 nf_defrag_ipv4 xt_conntrack nf_conntrack ebtable_filter ebtables ip6table_filter ip6_tables ext3 jbd ext2 iTCO_wdt iTCO_vendor_support coretemp snd_hda_codec_realtek microcode snd_hda_intel snd_hda_codec snd_hwdep snd_seq serio_raw snd_seq_device snd_pcm snd_page_alloc pcspkr snd_timer i2c_i801 lpc_ich mfd_core snd r8169 soundcore mii nfsd auth_rpcgss nfs_acl lockd sunrpc vhost_net tun macvtap macvlan kvm_intel kvm binfmt_misc uinput usb_storage firewire_ohci firewire_core crc_itu_t i915 video i2c_algo_bit drm_kms_helper drm i2c_core [19806.692131] Pid: 9609, comm: kworker/3:3 Not tainted 3.8.11-rt8+ #11 [19806.692134] Call Trace: [19806.692142] [<ffffffff81062c2f>] warn_slowpath_common+0x7f/0xc0 [19806.692145] [<ffffffff81062c8a>] warn_slowpath_null+0x1a/0x20 [19806.692147] [<ffffffff81080fa8>] worker_enter_idle+0xd8/0x130 [19806.692148] [<ffffffff81083fa7>] worker_thread+0x1f7/0x440 [19806.692151] [<ffffffff81083db0>] ? rescuer_thread+0x240/0x240 [19806.692153] [<ffffffff8108a57d>] kthread+0xcd/0xe0 [19806.692156] [<ffffffff8108a4b0>] ? kthread_create_on_node+0x140/0x140 [19806.692160] [<ffffffff8166106c>] ret_from_fork+0x7c/0xb0 [19806.692162] [<ffffffff8108a4b0>] ? kthread_create_on_node+0x140/0x140 [19806.692163] ---[ end trace 0000000000000002 ]--- -- [ Luis Claudio R. Goncalves Red Hat - Realtime Team ] [ Fingerprint: 4FDD B8C4 3C59 34BD 8BE9 2696 7203 D980 A448 C8F8 ] -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
