[IA64] New IA64 core/thread detection patch

IPF SDM 2.2 changes definition of PAL_LOGICAL_TO_PHYSICAL to add
proc_number=-1 to get core/thread mapping info on the running processer.

Based on this change, we had better to update existing core/thread
detection in IA64 kernel correspondingly. The attached patch implements
this change. It simplifies detection code and eliminates potential race
condition. It also runs a bit faster and has better scalability especially
when cores and threads number grows up in one package.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 4 insertions, 105 deletions

diff --git a/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
index c4b633b36dab..44e9547878ac 100644
--- a/arch/ia64/kernel/smpboot.c
+++ b/arch/ia64/kernel/smpboot.c
@@ -624,32 +624,8 @@ void __devinit smp_prepare_boot_cpu(void)
         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
 }
 
-/*
- * mt_info[] is a temporary store for all info returned by
- * PAL_LOGICAL_TO_PHYSICAL, to be copied into cpuinfo_ia64 when the
- * specific cpu comes.
- */
-static struct {
-        __u32   socket_id;
-        __u16   core_id;
-        __u16   thread_id;
-        __u16   proc_fixed_addr;
-        __u8    valid;
-} mt_info[NR_CPUS] __devinitdata;
-
 #ifdef CONFIG_HOTPLUG_CPU
 static inline void
-remove_from_mtinfo(int cpu)
-{
-        int i;
-
-        for_each_cpu(i)
-                if (mt_info[i].valid &&  mt_info[i].socket_id ==
-                                                cpu_data(cpu)->socket_id)
-                        mt_info[i].valid = 0;
-}
-
-static inline void
 clear_cpu_sibling_map(int cpu)
 {
         int i;
@@ -678,12 +654,6 @@ remove_siblinginfo(int cpu)
 
         /* remove it from all sibling map's */
         clear_cpu_sibling_map(cpu);
-
-        /* if this cpu is the last in the core group, remove all its info 
-         * from mt_info structure
-         */
-        if (last)
-                remove_from_mtinfo(cpu);
 }
 
 extern void fixup_irqs(void);
@@ -878,40 +848,6 @@ init_smp_config(void)
                        ia64_sal_strerror(sal_ret));
 }
 
-static inline int __devinit
-check_for_mtinfo_index(void)
-{
-        int i;
-        
-        for_each_cpu(i)
-                if (!mt_info[i].valid)
-                        return i;
-
-        return -1;
-}
-
-/*
- * Search the mt_info to find out if this socket's cid/tid information is
- * cached or not. If the socket exists, fill in the core_id and thread_id 
- * in cpuinfo
- */
-static int __devinit
-check_for_new_socket(__u16 logical_address, struct cpuinfo_ia64 *c)
-{
-        int i;
-        __u32 sid = c->socket_id;
-
-        for_each_cpu(i) {
-                if (mt_info[i].valid && mt_info[i].proc_fixed_addr == logical_address
-                    && mt_info[i].socket_id == sid) {
-                        c->core_id = mt_info[i].core_id;
-                        c->thread_id = mt_info[i].thread_id;
-                        return 1; /* not a new socket */
-                }
-        }
-        return 0;
-}
-
 /*
  * identify_siblings(cpu) gets called from identify_cpu. This populates the 
  * information related to logical execution units in per_cpu_data structure.
@@ -921,14 +857,12 @@ identify_siblings(struct cpuinfo_ia64 *c)
 {
         s64 status;
         u16 pltid;
-        u64 proc_fixed_addr;
-        int count, i;
         pal_logical_to_physical_t info;
 
         if (smp_num_cpucores == 1 && smp_num_siblings == 1)
                 return;
 
-        if ((status = ia64_pal_logical_to_phys(0, &info)) != PAL_STATUS_SUCCESS) {
+        if ((status = ia64_pal_logical_to_phys(-1, &info)) != PAL_STATUS_SUCCESS) {
                 printk(KERN_ERR "ia64_pal_logical_to_phys failed with %ld\n",
                        status);
                 return;
@@ -937,47 +871,12 @@ identify_siblings(struct cpuinfo_ia64 *c)
                 printk(KERN_ERR "ia64_sal_pltid failed with %ld\n", status);
                 return;
         }
-        if ((status = ia64_pal_fixed_addr(&proc_fixed_addr)) != PAL_STATUS_SUCCESS) {
-                printk(KERN_ERR "ia64_pal_fixed_addr failed with %ld\n", status);
-                return;
-        }
 
         c->socket_id =  (pltid << 8) | info.overview_ppid;
         c->cores_per_socket = info.overview_cpp;
         c->threads_per_core = info.overview_tpc;
-        count = c->num_log = info.overview_num_log;
+        c->num_log = info.overview_num_log;
 
-        /* If the thread and core id information is already cached, then
-         * we will simply update cpu_info and return. Otherwise, we will
-         * do the PAL calls and cache core and thread id's of all the siblings.
-         */
-        if (check_for_new_socket(proc_fixed_addr, c))
-                return;
-
-        for (i = 0; i < count; i++) {
-                int index;
-
-                if (i && (status = ia64_pal_logical_to_phys(i, &info))
-                          != PAL_STATUS_SUCCESS) {
-                        printk(KERN_ERR "ia64_pal_logical_to_phys failed"
-                                        " with %ld\n", status);
-                        return;
-                }
-                if (info.log2_la == proc_fixed_addr) {
-                        c->core_id = info.log1_cid;
-                        c->thread_id = info.log1_tid;
-                }
-
-                index = check_for_mtinfo_index();
-                /* We will not do the mt_info caching optimization in this case.
-                 */
-                if (index < 0)
-                        continue;
-
-                mt_info[index].valid = 1;
-                mt_info[index].socket_id = c->socket_id;
-                mt_info[index].core_id = info.log1_cid;
-                mt_info[index].thread_id = info.log1_tid;
-                mt_info[index].proc_fixed_addr = info.log2_la;
-        }
+        c->core_id = info.log1_cid;
+        c->thread_id = info.log1_tid;
 }