From: William Lee Irwin III <wli@holomorphy.com>
To: linux-kernel@vger.kernel.org
Cc: Martin.Bligh@us.ibm.com
Subject: NUMA-Q breakage 2/7 xquad_portio ioremap deadlock
Date: Fri, 12 Jul 2002 15:39:42 -0700 [thread overview]
Message-ID: <20020712223942.GZ25360@holomorphy.com> (raw)
The cpu_online_map stuff for hotplug cpu created a brand new bootstrap
ordering problem for NUMA-Q. The mmapped portio region needs to be
ioremapped early but ioremap attempts to do TLB shootdown, and
smp_call_function() (called by flush_tlb_all()) deadlocks when
cpu_online_map is uninitialized.
Workaround (due to Matt Dobson) below.
diff -Nur linux-2.5.23-vanilla/arch/i386/kernel/smp.c linux-2.5.23-patched/arch/i386/kernel/smp.c
--- linux-2.5.23-vanilla/arch/i386/kernel/smp.c Tue Jun 18 19:11:47 2002
+++ linux-2.5.23-patched/arch/i386/kernel/smp.c Mon Jul 8 14:52:32 2002
@@ -569,7 +569,7 @@
struct call_data_struct data;
int cpus = num_online_cpus()-1;
- if (!cpus)
+ if (cpus <= 0)
return 0;
data.func = func;
next reply other threads:[~2002-07-12 22:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-12 22:39 William Lee Irwin III [this message]
2002-07-12 22:58 ` NUMA-Q breakage 2/7 xquad_portio ioremap deadlock Martin J. Bligh
2002-07-12 23:04 ` William Lee Irwin III
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