From 839052d27e8db0c1545256fe5827abcd00fb51c5 Mon Sep 17 00:00:00 2001 From: "Huang, Xiaolan" Date: Thu, 15 May 2008 10:18:41 +0800 Subject: [IA64] fix personality(PER_LINUX32) performance issue The patch aims to fix a performance issue for the syscall personality(PER_LINUX32). On IA-64 box, the syscall personality (PER_LINUX32) has poor performance because it failed to find the Linux/x86 execution domain. Then it tried to load the kernel module however it failed always and it used the default execution domain PER_LINUX instead. Requesting kernel modules is very expensive. It caused the performance issue. (see the function lookup_exec_domain in kernel/exec_domain.c). To resolve the issue, execution domain Linux/x86 is always registered in initialization time for IA-64 architecture. Signed-off-by: Xiaolan Huang Signed-off-by: Tony Luck --- arch/ia64/mm/init.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) (limited to 'arch/ia64/mm/init.c') diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c index fc6c6636ffda..200100ea7610 100644 --- a/arch/ia64/mm/init.c +++ b/arch/ia64/mm/init.c @@ -719,3 +719,28 @@ out: EXPORT_SYMBOL_GPL(remove_memory); #endif /* CONFIG_MEMORY_HOTREMOVE */ #endif + +/* + * Even when CONFIG_IA32_SUPPORT is not enabled it is + * useful to have the Linux/x86 domain registered to + * avoid an attempted module load when emulators call + * personality(PER_LINUX32). This saves several milliseconds + * on each such call. + */ +static struct exec_domain ia32_exec_domain; + +static int __init +per_linux32_init(void) +{ + ia32_exec_domain.name = "Linux/x86"; + ia32_exec_domain.handler = NULL; + ia32_exec_domain.pers_low = PER_LINUX32; + ia32_exec_domain.pers_high = PER_LINUX32; + ia32_exec_domain.signal_map = default_exec_domain.signal_map; + ia32_exec_domain.signal_invmap = default_exec_domain.signal_invmap; + register_exec_domain(&ia32_exec_domain); + + return 0; +} + +__initcall(per_linux32_init); -- cgit v1.2.3