xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

[IA64] fix personality(PER_LINUX32) performance issue

Browse Source 
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>
This commit is contained in:
Huang, Xiaolan
2008-05-15 10:18:41 +08:00
committed by Tony Luck
parent 3fb2c74ee2
commit 839052d27e
2 changed files with 25 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

25
arch/ia64/mm/init.c
View File

@@ -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);