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Subject[PATCH 2/2] um: Disable CONFIG_CMPXCHG_LOCAL
Date
Commit 8a5ec0ba "Lockless (and preemptless) fastpaths for slub"
makes use of this_cpu_cmpxchg_double() which needs
this_cpu_cmpxchg16b_emu() on x86_64.
Implementing cmpxchg16b emulation for UML would introduce
too much complexity. So just disable it.

LKML-Reference: <20110412192014.GF16342@mtj.dyndns.org>
Reported-by: Sergei Trofimovich <slyich@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---
arch/um/Kconfig.x86 | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/arch/um/Kconfig.x86 b/arch/um/Kconfig.x86
index 02fb017..a9da516 100644
--- a/arch/um/Kconfig.x86
+++ b/arch/um/Kconfig.x86
@@ -4,6 +4,10 @@ menu "UML-specific options"

menu "Host processor type and features"

+config CMPXCHG_LOCAL
+ bool
+ default n
+
source "arch/x86/Kconfig.cpu"

endmenu
--
1.6.6.1


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