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Subject[Patch 2/2] x86, x86_64: fix Intel cache detection code assumption about threads sharing
On Thu, Oct 13, 2005 at 02:10:22AM +0200, Andi Kleen wrote:
> Ok, if you rename the variable to make it clear
>
> x86_num_cores -> x86_max_cores

Updated patch 2/2 in the context of this change.

Andrew, please apply.

thanks,
suresh
--

Fix the Intel cache detection code assumption that number of threads sharing the
cache will either be equal to number of HT or core siblings.

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

diff -pNru linux-2.6.14-rc3/arch/i386/kernel/cpu/intel_cacheinfo.c linux/arch/i386/kernel/cpu/intel_cacheinfo.c
--- linux-2.6.14-rc3/arch/i386/kernel/cpu/intel_cacheinfo.c 2005-09-30 14:17:35.000000000 -0700
+++ linux/arch/i386/kernel/cpu/intel_cacheinfo.c 2005-10-07 16:27:37.708580280 -0700
@@ -303,29 +303,45 @@ static struct _cpuid4_info *cpuid4_info[
#ifdef CONFIG_SMP
static void __devinit cache_shared_cpu_map_setup(unsigned int cpu, int index)
{
- struct _cpuid4_info *this_leaf;
+ struct _cpuid4_info *this_leaf, *sibling_leaf;
unsigned long num_threads_sharing;
-#ifdef CONFIG_X86_HT
- struct cpuinfo_x86 *c = cpu_data + cpu;
-#endif
+ int index_msb, i;
+ struct cpuinfo_x86 *c = cpu_data;

this_leaf = CPUID4_INFO_IDX(cpu, index);
num_threads_sharing = 1 + this_leaf->eax.split.num_threads_sharing;

if (num_threads_sharing == 1)
cpu_set(cpu, this_leaf->shared_cpu_map);
-#ifdef CONFIG_X86_HT
- else if (num_threads_sharing == smp_num_siblings)
- this_leaf->shared_cpu_map = cpu_sibling_map[cpu];
- else if (num_threads_sharing == (c->x86_max_cores * smp_num_siblings))
- this_leaf->shared_cpu_map = cpu_core_map[cpu];
- else
- printk(KERN_DEBUG "Number of CPUs sharing cache didn't match "
- "any known set of CPUs\n");
-#endif
+ else {
+ index_msb = get_count_order(num_threads_sharing);
+
+ for_each_online_cpu(i) {
+ if (c[i].apicid >> index_msb ==
+ c[cpu].apicid >> index_msb) {
+ cpu_set(i, this_leaf->shared_cpu_map);
+ if (i != cpu && cpuid4_info[i]) {
+ sibling_leaf = CPUID4_INFO_IDX(i, index);
+ cpu_set(cpu, sibling_leaf->shared_cpu_map);
+ }
+ }
+ }
+ }
+}
+static void __devinit cache_remove_shared_cpu_map(unsigned int cpu, int index)
+{
+ struct _cpuid4_info *this_leaf, *sibling_leaf;
+ int sibling;
+
+ this_leaf = CPUID4_INFO_IDX(cpu, index);
+ for_each_cpu_mask(sibling, this_leaf->shared_cpu_map) {
+ sibling_leaf = CPUID4_INFO_IDX(sibling, index);
+ cpu_clear(cpu, sibling_leaf->shared_cpu_map);
+ }
}
#else
static void __init cache_shared_cpu_map_setup(unsigned int cpu, int index) {}
+static void __init cache_remove_shared_cpu_map(unsigned int cpu, int index) {}
#endif

static void free_cache_attributes(unsigned int cpu)
@@ -584,8 +600,10 @@ static int __devexit cache_remove_dev(st
unsigned int cpu = sys_dev->id;
unsigned long i;

- for (i = 0; i < num_cache_leaves; i++)
+ for (i = 0; i < num_cache_leaves; i++) {
+ cache_remove_shared_cpu_map(cpu, i);
kobject_unregister(&(INDEX_KOBJECT_PTR(cpu,i)->kobj));
+ }
kobject_unregister(cache_kobject[cpu]);
cpuid4_cache_sysfs_exit(cpu);
return 0;
-
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