[patch 3/4] CPU Hotplug support for X86_64

Ashok Raj
2005-05-24T08:32:20Z

[-- Attachment #1: x86_64-sibling-map-fixup.patch --]
[-- Type: text/plain, Size: 3869 bytes --]

Subject: [patch 3/4] x86_64: CPU hotplug sibling map cleanup
From: Ashok Raj <ashok.raj@intel.com>

This patch is a minor cleanup to the cpu sibling/core map.
It is required that this setup happens on a per-cpu bringup
time.

Signed-off-by: Ashok Raj <ashok.raj@intel.com>

------------------------------
smpboot.c | 89 ++++++++++++++++++++++++++++----------------------------------
1 files changed, 41 insertions(+), 48 deletions(-)

Index: linux-2.6.12-rc4-mm2/arch/x86_64/kernel/smpboot.c
===================================================================
--- linux-2.6.12-rc4-mm2.orig/arch/x86_64/kernel/smpboot.c
+++ linux-2.6.12-rc4-mm2/arch/x86_64/kernel/smpboot.c
@@ -62,9 +62,12 @@
/* Number of siblings per CPU package */
int smp_num_siblings = 1;
/* Package ID of each logical CPU */
-u8 phys_proc_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
-u8 cpu_core_id[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
+u8 phys_proc_id[NR_CPUS] __cacheline_aligned =
+ { [0 ... NR_CPUS-1] = BAD_APICID };
EXPORT_SYMBOL(phys_proc_id);
+
+u8 cpu_core_id[NR_CPUS] __cacheline_aligned =
+ { [0 ... NR_CPUS-1] = BAD_APICID };
EXPORT_SYMBOL(cpu_core_id);

/* Bitmask of currently online CPUs */
@@ -434,6 +437,34 @@ void __cpuinit smp_callin(void)
local_flush_tlb();
}

+static inline void
+set_cpu_sibling_map(int cpu)
+{
+ int i;
+
+ if (smp_num_siblings > 1) {
+ for_each_online_cpu(i) {
+ if (cpu_core_id[cpu] == cpu_core_id[i]) {
+ cpu_set(i, cpu_sibling_map[cpu]);
+ cpu_set(cpu, cpu_sibling_map[i]);
+ }
+ }
+ } else {
+ cpu_set(cpu, cpu_sibling_map[cpu]);
+ }
+
+ if (current_cpu_data.x86_num_cores > 1) {
+ for_each_online_cpu(i) {
+ if (phys_proc_id[cpu] == phys_proc_id[i]) {
+ cpu_set(i, cpu_core_map[cpu]);
+ cpu_set(cpu, cpu_core_map[i]);
+ }
+ }
+ } else {
+ cpu_core_map[cpu] = cpu_sibling_map[cpu];
+ }
+}
+
/*
* Setup code on secondary processor (after comming out of the trampoline)
*/
@@ -463,6 +494,12 @@ void __cpuinit start_secondary(void)

enable_APIC_timer();

+ /*
+ * The sibling maps must be set before turing the online map on for
+ * this cpu
+ */
+ set_cpu_sibling_map(smp_processor_id());
+
/*
* Allow the master to continue.
*/
@@ -798,51 +835,6 @@ cycles_t cacheflush_time;
unsigned long cache_decay_ticks;

/*
- * Construct cpu_sibling_map[], so that we can tell the sibling CPU
- * on SMT systems efficiently.
- */
-static __cpuinit void detect_siblings(void)
-{
- int cpu;
-
- for (cpu = 0; cpu < NR_CPUS; cpu++) {
- cpus_clear(cpu_sibling_map[cpu]);
- cpus_clear(cpu_core_map[cpu]);
- }
-
- for_each_online_cpu (cpu) {
- struct cpuinfo_x86 *c = cpu_data + cpu;
- int siblings = 0;
- int i;
- if (smp_num_siblings > 1) {
- for_each_online_cpu (i) {
- if (cpu_core_id[cpu] == cpu_core_id[i]) {
- siblings++;
- cpu_set(i, cpu_sibling_map[cpu]);
- }
- }
- } else {
- siblings++;
- cpu_set(cpu, cpu_sibling_map[cpu]);
- }
-
- if (siblings != smp_num_siblings) {
- printk(KERN_WARNING
- "WARNING: %d siblings found for CPU%d, should be %d\n",
- siblings, cpu, smp_num_siblings);
- smp_num_siblings = siblings;
- }
- if (c->x86_num_cores > 1) {
- for_each_online_cpu(i) {
- if (phys_proc_id[cpu] == phys_proc_id[i])
- cpu_set(i, cpu_core_map[cpu]);
- }
- } else
- cpu_core_map[cpu] = cpu_sibling_map[cpu];
- }
-}
-
-/*
* Cleanup possible dangling ends...
*/
static __cpuinit void smp_cleanup_boot(void)
@@ -1036,6 +1028,8 @@ void __init smp_prepare_boot_cpu(void)
int me = smp_processor_id();
cpu_set(me, cpu_online_map);
cpu_set(me, cpu_callout_map);
+ cpu_set(0, cpu_sibling_map[0]);
+ cpu_set(0, cpu_core_map[0]);
}

/*
@@ -1100,7 +1094,6 @@ void __init smp_cpus_done(unsigned int m
setup_ioapic_dest();
#endif

- detect_siblings();
time_init_gtod();

check_nmi_watchdog();

--