[tip:irq/urgent] x86/irq: mark NUMA_MIGRATE_IRQ_DESC broken

From: tip-bot for Yinghai Lu
Date: Thu Apr 16 2009 - 21:23:18 EST


Commit-ID: ca713c2ab0eea3458962983e4a7e13430ea479b8
Gitweb: http://git.kernel.org/tip/ca713c2ab0eea3458962983e4a7e13430ea479b8
Author: Yinghai Lu <yinghai@xxxxxxxxxx>
AuthorDate: Wed, 15 Apr 2009 18:39:13 -0700
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Fri, 17 Apr 2009 03:20:01 +0200

x86/irq: mark NUMA_MIGRATE_IRQ_DESC broken

It causes crash on system with lots of cards with MSI-X
when irq_balancer enabled...

The patches fixing it were both complex and fragile, according
to Eric they were also doing quite dangerous things to the
hardware.

Instead we now have patches that solve this problem via static
NUMA node mappings - not dynamic allocation and balancing.

The patches are much simpler than this method but are still too
large outside of the merge window, so we mark the dynamic balancer
as broken for now, and queue up the new approach for v2.6.31.

[ Impact: deactivate broken kernel feature ]

Reported-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
Cc: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
LKML-Reference: <49E68C41.4020801@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>


---
arch/x86/Kconfig | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index bc25b9f..b1d2be7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -277,6 +277,7 @@ config SPARSE_IRQ
config NUMA_MIGRATE_IRQ_DESC
bool "Move irq desc when changing irq smp_affinity"
depends on SPARSE_IRQ && NUMA
+ depends on BROKEN
default n
---help---
This enables moving irq_desc to cpu/node that irq will use handled.
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