On Mon, Feb 04, 2008 at 03:35:13PM -0800, Max Krasnyanskiy wrote: > This is just an FYI. As part of the "Isolated CPU extensions" thread Daniel suggest for me > to check out latest RT kernels. So I did or at least tried to and immediately spotted a couple > of issues. > > The machine I'm running it on is: > HP xw9300, Dual Opteron, NUMA > > It looks like with -rt kernel IRQ affinity masks are ignored on that > system. ie I write 1 to lets say /proc/irq/23/smp_affinity but the > interrupts keep coming to CPU1. Vanilla 2.6.24 does not have that issue. I tried this, and it works according to /proc/interrupts .. Are you looking at the interrupt threads affinity? > Also the first thing I tried was to bring CPU1 off-line. Thats the fastest > way to get irqs, soft-irqs, timers, etc of a CPU. But the box hung > completely. It also managed to mess up my ext3 filesystem to the point > where it required manual fsck (have not see that for a couple of > years now). I tried the same thing (ie echo 0 > > /sys/devices/cpu/cpu1/online) from the console. It hang again with the > message that looked something like: > CPU1 is now off-line > Thread IRQ-23 is on CPU1 ... I get the following when I tried it, BUG: sleeping function called from invalid context bash(5126) at kernel/rtmutex.c:638 in_atomic():1 [00000001], irqs_disabled():1 Pid: 5126, comm: bash Not tainted 2.6.24-rt1 #1 [<c010506b>] show_trace_log_lvl+0x1d/0x3a [<c01059cd>] show_trace+0x12/0x14 [<c0106151>] dump_stack+0x6c/0x72 [<c011d153>] __might_sleep+0xe8/0xef [<c03b2326>] __rt_spin_lock+0x24/0x59 [<c03b2363>] rt_spin_lock+0x8/0xa [<c0165b2f>] kfree+0x2c/0x8d [<c011eacb>] rq_attach_root+0x67/0xba [<c01209ae>] cpu_attach_domain+0x2b6/0x2f7 [<c0120a12>] detach_destroy_domains+0x23/0x37 [<c0121368>] update_sched_domains+0x2d/0x40 [<c013b482>] notifier_call_chain+0x2b/0x55 [<c013b4d9>] __raw_notifier_call_chain+0x19/0x1e [<c01420d3>] _cpu_down+0x84/0x24c [<c01422c3>] cpu_down+0x28/0x3a [<c029f59e>] store_online+0x27/0x5a [<c029c9dc>] sysdev_store+0x20/0x25 [<c019a695>] sysfs_write_file+0xad/0xde [<c0169929>] vfs_write+0x82/0xb8 [<c0169e2a>] sys_write+0x3d/0x61 [<c0104072>] sysenter_past_esp+0x5f/0x85 ======================= --------------------------- | preempt count: 00000001 ] | 1-level deep critical section nesting: ---------------------------------------- .. [<c03b25e2>] .... __spin_lock_irqsave+0x14/0x3b .....[<c011ea76>] .. ( <= rq_attach_root+0x12/0xba) Which is clearly a problem .. (I added linux-rt-users to the CC) Daniel - 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
