[RFC 2/6]cpu_sibling_map rework

From: Li Shaohua
Date: Sun Apr 03 2005 - 21:16:26 EST



Make sibling map init per-cpu. Hotplug CPU may change the map at runtime.
cpuhotplug semaphore should be used to protect the map.


Thanks,
Shaohua

---

linux-2.6.11-root/arch/i386/kernel/smpboot.c | 56 +++++++++++++--------------
1 files changed, 29 insertions(+), 27 deletions(-)

diff -puN arch/i386/kernel/smpboot.c~sibling_map_init_cleanup arch/i386/kernel/smpboot.c
--- linux-2.6.11/arch/i386/kernel/smpboot.c~sibling_map_init_cleanup 2005-03-28 16:29:55.000000000 +0800
+++ linux-2.6.11-root/arch/i386/kernel/smpboot.c 2005-03-31 10:46:51.572700184 +0800
@@ -63,9 +63,12 @@ static int __initdata smp_b_stepping;

/* Number of siblings per CPU package */
int smp_num_siblings = 1;
-int phys_proc_id[NR_CPUS]; /* Package ID of each logical CPU */
+/* Package ID of each logical CPU */
+int phys_proc_id[NR_CPUS] = {[0 ... NR_CPUS-1] = BAD_APICID};
EXPORT_SYMBOL(phys_proc_id);

+cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
+
/* bitmap of online cpus */
cpumask_t cpu_online_map;

@@ -422,6 +425,9 @@ extern void enable_sep_cpu(void *);
*/
static void __init start_secondary(void *unused)
{
+ int siblings = 0;
+ int i;
+ int self = smp_processor_id();
/*
* Dont put anything before smp_callin(), SMP
* booting is too fragile that we want to limit the
@@ -443,6 +449,27 @@ static void __init start_secondary(void
* the local TLBs too.
*/
local_flush_tlb();
+
+ /* This must be doen before setting cpu_online_map */
+ if (smp_num_siblings > 1) {
+ for (i = 0; i < NR_CPUS; i++) {
+ if (!cpu_isset(i, cpu_callout_map))
+ continue;
+ if (phys_proc_id[self] == phys_proc_id[i]) {
+ siblings ++;
+ cpu_set(i, cpu_sibling_map[self]);
+ cpu_set(self, cpu_sibling_map[i]);
+ }
+ }
+ } else {
+ siblings ++;
+ cpu_set(self, cpu_sibling_map[self]);
+ }
+
+ if (siblings != smp_num_siblings)
+ printk(KERN_WARNING "WARNING: %d siblings found for CPU%d, should be %d\n", siblings, self, smp_num_siblings);
+ wmb();
+
cpu_set(smp_processor_id(), cpu_online_map);

/* We can take interrupts now: we're officially "up". */
@@ -893,8 +920,6 @@ static int boot_cpu_logical_apicid;
/* Where the IO area was mapped on multiquad, always 0 otherwise */
void *xquad_portio;

-cpumask_t cpu_sibling_map[NR_CPUS] __cacheline_aligned;
-
static void __init smp_boot_cpus(unsigned int max_cpus)
{
int apicid, cpu, bit, kicked;
@@ -1049,30 +1074,7 @@ static void __init smp_boot_cpus(unsigne
*/
for (cpu = 0; cpu < NR_CPUS; cpu++)
cpus_clear(cpu_sibling_map[cpu]);
-
- for (cpu = 0; cpu < NR_CPUS; cpu++) {
- int siblings = 0;
- int i;
- if (!cpu_isset(cpu, cpu_callout_map))
- continue;
-
- if (smp_num_siblings > 1) {
- for (i = 0; i < NR_CPUS; i++) {
- if (!cpu_isset(i, cpu_callout_map))
- continue;
- if (phys_proc_id[cpu] == phys_proc_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);
- }
+ cpu_set(0, cpu_sibling_map[0]);

if (nmi_watchdog == NMI_LOCAL_APIC)
check_nmi_watchdog();
_


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/