From: Gerald Schaefer Date: Wed, 5 Jan 2011 11:48:14 +0000 (+0100) Subject: [S390] mutex: Introduce arch_mutex_cpu_relax() X-Git-Tag: v2.6.38-rc1~461^2~4 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=34b133f8e94e39ff3cf4d1c1f67f2e07cdc3d54e;p=pandora-kernel.git [S390] mutex: Introduce arch_mutex_cpu_relax() The spinning mutex implementation uses cpu_relax() in busy loops as a compiler barrier. Depending on the architecture, cpu_relax() may do more than needed in this specific mutex spin loops. On System z we also give up the time slice of the virtual cpu in cpu_relax(), which prevents effective spinning on the mutex. This patch replaces cpu_relax() in the spinning mutex code with arch_mutex_cpu_relax(), which can be defined by each architecture that selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so this patch should not affect other architectures than System z for now. Signed-off-by: Gerald Schaefer Signed-off-by: Peter Zijlstra LKML-Reference: <1290437256.7455.4.camel@thinkpad> Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed