Re: [ANNOUNCE] 2.6.33-rc8-rt1

John Kacur
2010-02-22T11:11:28Z

On Mon, Feb 22, 2010 at 12:24 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> We are pleased to announce the next update to our new preempt-rt
> series.
>
>    - Forward to 2.6.33-rc8
>
> Finally I managed to get that beast tamed.
>
> Some folks were already joking, that my dog ate the 33-rt patch. The
> truth is that my reject fixup skills were one line off in the mm/*
> code which resulted in -rt eating my files :)
>
> When I fixed the wreckage of my own stupidty I found out that -rt
> triggered a nasty and hard to reproduce mainline scheduler bug, which
> refused to reproduce with kernel tracing enabled. Thanks to Peter
> Zijlstra for helping me to decode the initial mainline problem and the
> ones which resulted from fixing the mainline bug!
>
> It's all fixed now and I'm pretty happy about the state of this
> release with the following exceptions:
>
>  1) it is only runtime tested on x86_64 (compiles on x86_32, arm,
>    powerpc_32/64).
>
>    I'm going to throw it at my testing infrastructure tomorrow, but I
>    wanted to release this before .33-final and of course you folks
>    are heartely invited to help out with fixing the fallout :)
>
>  2) I broke the histogram tracer stuff simply because I got lost in
>    the divergence of -rt and mainline kernel/trace/* changes
>
>    I apologize to Carsten, but I'm sure he will fix that in no time
>    as usual
>
> The current state of the patch on x86_64 is: rock stable!
>
>    [rt-tests]# chrt -f 1 ./cyclictest -t -a -n -d0 -p80 -i125
>    policy: fifo: loadavg: 509.19 490.53 486.66 364/1055 31899
>
>    T: 0 (27682) P:80 I:125 C:1170997397 Min: 2 Act: 3 Avg: 3 Max: 34
>    T: 1 (27683) P:79 I:125 C:1170997397 Min: 2 Act: 3 Avg: 3 Max: 34
>
>    That's an uptime of ~1.6 days with a load of hackbench, recursive
>    grep and extensive networking traffic going on.
>
> The merge of the spinlock namespace cleanup and the initial
> annotations took a big chunk away from the -rt patch size:
>
>        patch-2.6.31.12-rt21.patch     1680354
>        patch-2.6.33-rc8.patch         1179390
>        patch-2.6.33-rc8+git.patch     1067064
>
> We are zooming in, but there is still a way to go!
>

Woohoo! More -rt fun.

Unfortunately, I can't log in on my T500 with this kernel though.
The following shows-up on my serial console.
------------[ cut here ]------------
WARNING: at /home/jkacur/rt.linux.git/net/mac80211/rx.c:2467 ieee80211_rx+0x4c/0
x721 [mac80211]()
Hardware name: 2241B48
Modules linked in: bridge stp bnep sco btusb l2cap crc16 bluetooth sunrpc ipt_RE
JECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT xt_tc
pudp nf_conntrack_ipv6 xt_state ip6table_filter ip6_tables x_tables ipv6 cpufreq
_ondemand acpi_cpufreq ext3 jbd mbcache dm_mirror dm_region_hash dm_log dm_multi
path scsi_dh dm_mod kvm_intel kvm uinput arc4 ecb snd_hda_codec_conexant iwlagn
snd_hda_intel iwlcore snd_hda_codec snd_hwdep snd_seq_dummy mac80211 snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss thinkpad_ac
pi snd_pcm firewire_ohci firewire_core hwmon video ppdev tpm_tis cfg80211 sr_mod
battery wmi ricoh_mmc parport_pc sg tpm cdrom tpm_bios button ac ata_generic e1
000e iTCO_wdt snd_timer sdhci_pci pata_acpi sdhci i2c_i801 i2c_core parport mmc_
core iTCO_vendor_support snd joydev snd_page_alloc pcspkr intel_agp soundcore cr
c_itu_t rfkill output ahci libata sd_mod scsi_mod crc_t10dif xfs exportfs uhci_h
cd ohci_hcd ehci_hcd [last unloaded: microcode]
Pid: 10, comm: sirq-tasklet/0 Not tainted 2.6.33-rc8-rt1-debug #1
Call Trace:
[<ffffffffa033524f>] ? ieee80211_rx+0x4c/0x721 [mac80211]
[<ffffffff81041f25>] warn_slowpath_common+0x77/0xa4
[<ffffffff81041f61>] warn_slowpath_null+0xf/0x11
[<ffffffffa033524f>] ieee80211_rx+0x4c/0x721 [mac80211]
[<ffffffffa039f380>] ? iwl_led_pattern+0x17a/0x189 [iwlcore]
[<ffffffff810c0fd1>] ? free_compound_page+0x16/0x18
[<ffffffffa039f3f5>] ? iwl_leds_background+0x66/0x219 [iwlcore]
[<ffffffffa0393524>] iwl_rx_reply_rx+0xc29/0xc5a [iwlcore]
[<ffffffff8106ee74>] ? trace_hardirqs_on+0xd/0xf
[<ffffffff8135cf7e>] ? _raw_spin_unlock_irqrestore+0x4c/0x68
[<ffffffff811b4e32>] ? unmap_single+0x27/0x4f
[<ffffffffa03cec81>] iwl_rx_handle+0x2a0/0x48d [iwlagn]
[<ffffffff8135cf7e>] ? _raw_spin_unlock_irqrestore+0x4c/0x68
[<ffffffffa03cfbb3>] iwl_irq_tasklet+0x5a3/0x73f [iwlagn]
[<ffffffff81047b5a>] __tasklet_action+0x8f/0xfd
[<ffffffff81047cc9>] tasklet_action+0x7c/0x85
[<ffffffff81048209>] run_ksoftirqd+0x18e/0x2d5
[<ffffffff8104807b>] ? run_ksoftirqd+0x0/0x2d5
[<ffffffff8105d794>] kthread+0x8c/0x94
[<ffffffff8135cfca>] ? _raw_spin_unlock+0x30/0x4b
[<ffffffff81003a54>] kernel_thread_helper+0x4/0x10
[<ffffffff8135d340>] ? restore_args+0x0/0x30
[<ffffffff8105d708>] ? kthread+0x0/0x94
[<ffffffff81003a50>] ? kernel_thread_helper+0x0/0x10
---[ end trace 01358557eee38037 ]---

Thanks