diff options
author | Huang, Xiaolan <xiaolan.huang@intel.com> | 2008-05-15 10:18:41 +0800 |
---|---|---|
committer | Tony Luck <tony.luck@intel.com> | 2008-05-15 09:54:19 -0700 |
commit | 839052d27e8db0c1545256fe5827abcd00fb51c5 (patch) | |
tree | 003839d444943ba8f125846e776b068721da2c8f /arch/ia64/mm/init.c | |
parent | 3fb2c74ee20b77affd494c6b8ce7928d0ebbb62e (diff) |
[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 <xiaolan.huang@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/mm/init.c')
-rw-r--r-- | arch/ia64/mm/init.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/ia64/mm/init.c b/arch/ia64/mm/init.c index fc6c6636ffd..200100ea761 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); |