From: Richard Weinberger <richard@nod.at>
To: akpm@linux-foundation.com
Cc: slyich@gmail.com, linux-kernel@vger.kernel.org,
jdike@addtoit.com, user-mode-linux-devel@lists.sourceforge.net,
Richard Weinberger <richard@nod.at>
Subject: [PATCH 2/2] um: Disable CONFIG_CMPXCHG_LOCAL
Date: Wed, 13 Apr 2011 14:41:52 +0200 [thread overview]
Message-ID: <1302698512-11979-2-git-send-email-richard@nod.at> (raw)
In-Reply-To: <1302698512-11979-1-git-send-email-richard@nod.at>
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
next prev parent reply other threads:[~2011-04-13 12:42 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-13 12:41 [PATCH 1/2] um: Fix call tracer and bug handler Richard Weinberger
2011-04-13 12:41 ` Richard Weinberger [this message]
2011-04-13 12:56 ` [PATCH 2/2] um: Disable CONFIG_CMPXCHG_LOCAL Pekka Enberg
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