renegade-project/linux-next
2
0
Fork 0
mirror of https://github.com/edk2-porting/linux-next.git synced 2024-11-19 16:14:13 +08:00
Code

x86, apic: use logical flat for systems with <= 8 logical cpus

Browse Source 
We can use logical flat mode if there are <= 8 logical cpu's
(irrespective of physical apic id values).  This will enable simplified
and efficient IPI and device interrupt routing on such platforms.

This has been tested to work on both Intel and AMD platforms.
Exceptions like IBM summit platform which can't use logical flat mode
are addressed by using OEM platform checks.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Chris McDermott <lcm@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Suresh Siddha 2010-01-18 12:10:49 -08:00 committed by Linus Torvalds
parent dfea91d5a7
commit bb668da6d6
2 changed files with 4 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
arch/x86/kernel/apic/apic.c
View File

@ -61,12 +61,6 @@ unsigned int boot_cpu_physical_apicid = -1U;
/*
* The highest APIC ID seen during enumeration.
*
* This determines the messaging protocol we can use: if all APIC IDs
* are in the 0 ... 7 range, then we can use logical addressing which
* has some performance advantages (better broadcasting).
*
* If there's an APIC ID above 8, we use physical addressing.
*/
unsigned int max_physical_apicid;
@ -1898,14 +1892,7 @@ void __cpuinit generic_processor_info(int apicid, int version)
max_physical_apicid = apicid;
#ifdef CONFIG_X86_32
/*
* Would be preferable to switch to bigsmp when CONFIG_HOTPLUG_CPU=y
* but we need to work other dependencies like SMP_SUSPEND etc
* before this can be done without some confusion.
* if (CPU_HOTPLUG_ENABLED || num_processors > 8)
* - Ashok Raj <ashok.raj@intel.com>
*/
if (max_physical_apicid >= 8) {
if (num_processors > 8) {
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
if (!APIC_XAPIC(version)) {

8
arch/x86/kernel/apic/probe_64.c
View File

@ -64,15 +64,13 @@ void __init default_setup_apic_routing(void)
apic = &apic_x2apic_phys;
else
apic = &apic_x2apic_cluster;
printk(KERN_INFO "Setting APIC routing to %s\n", apic->name);
}
#endif
if (apic == &apic_flat) {
if (max_physical_apicid >= 8)
if (apic == &apic_flat && num_processors > 8)
apic = &apic_physflat;
printk(KERN_INFO "Setting APIC routing to %s\n", apic->name);
}
printk(KERN_INFO "Setting APIC routing to %s\n", apic->name);
if (is_vsmp_box()) {
/* need to update phys_pkg_id */