On Tue, 20 Oct 2009, Tejun Heo wrote: > > How about this one? (untested) > > > > From: Jiri Kosina <jkosina@xxxxxxx> > > Subject: sched: move rq_weight data array out of .percpu > > > > Commit 34d76c41 introduced percpu array update_shares_data, size of which > > being proportional to NR_CPUS. Unfortunately this blows up ia64 for large > > NR_CPUS configuration, as ia64 allows only 64k for .percpu section. > > > > Fix this by allocating this array dynamically and keep only pointer to it > > percpu. > > If the structure can be dynamically allocated at all, just using > percpu_alloc() to allocate the whole thing should solve it with the > correct numa locality. Unfortunately it's not that straightforward and easy, as we can't simply call __alloc_percpu from sched_init(). The reason is that does spin_unlock_irq(), and in sched_init() time it's too early for that, so we end up with WARNING: at kernel/lockdep.c:2311 trace_hardirqs_on_caller+0xd2/0x1a0() Hardware name: Kfisher HT2100 HT1000 Modules linked in: Pid: 0, comm: swapper Not tainted 2.6.32-rc5-default #66 Call Trace: [<ffffffff81086a62>] ? trace_hardirqs_on_caller+0xd2/0x1a0 [<ffffffff81054528>] warn_slowpath_common+0x78/0xd0 [<ffffffff81356b8b>] ? _spin_unlock_irq+0x2b/0x40 [<ffffffff8105458f>] warn_slowpath_null+0xf/0x20 [<ffffffff81086a62>] trace_hardirqs_on_caller+0xd2/0x1a0 [<ffffffff81086b3d>] trace_hardirqs_on+0xd/0x10 [<ffffffff81356b8b>] _spin_unlock_irq+0x2b/0x40 [<ffffffff811154c1>] pcpu_extend_area_map+0x41/0x110 [<ffffffff81115ce0>] pcpu_alloc+0x120/0x890 [<ffffffff81084577>] ? trace_hardirqs_off_caller+0x67/0xa0 [<ffffffff8108578d>] ? trace_hardirqs_off+0xd/0x10 [<ffffffff8111646b>] __alloc_percpu+0xb/0x10 [<ffffffff81712215>] sched_init+0x147/0x5d2 [<ffffffff816fabca>] start_kernel+0x1fc/0x40c [<ffffffff816fa299>] x86_64_start_reservations+0x99/0xb9 [<ffffffff816fa3bf>] x86_64_start_kernel+0x106/0x121 [<ffffffff816fa140>] ? early_idt_handler+0x0/0x71 ---[ end trace 4eaa2a86a8e2da22 ]--- start_kernel(): bug: interrupts were enabled *very* early, fixing it -- Jiri Kosina SUSE Labs, Novell Inc. -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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