[IA64] __per_cpu_idtrs[] is a memory hog

__per_cpu_idtrs is statically allocated ... on CONFIG_NR_CPUS=4096
systems it hogs 16MB of memory. This is way too much for a quite
probably unused facility (only KVM uses dynamic TR registers).

Change to an array of pointers, and allocate entries as needed on
a per cpu basis.  Change the name too as the __per_cpu_ prefix is
confusing (this isn't a classic <linux/percpu.h> type object).

Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 19 insertions, 13 deletions

diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index ee09d261f2e6..f3de9d7a98b4 100644
--- a/arch/ia64/mm/tlb.c
+++ b/arch/ia64/mm/tlb.c
@@ -48,7 +48,7 @@ DEFINE_PER_CPU(u8, ia64_need_tlb_flush);
 DEFINE_PER_CPU(u8, ia64_tr_num);  /*Number of TR slots in current processor*/
 DEFINE_PER_CPU(u8, ia64_tr_used); /*Max Slot number used by kernel*/
 
-struct ia64_tr_entry __per_cpu_idtrs[NR_CPUS][2][IA64_TR_ALLOC_MAX];
+struct ia64_tr_entry *ia64_idtrs[NR_CPUS];
 
 /*
  * Initializes the ia64_ctx.bitmap array based on max_ctx+1.
@@ -429,10 +429,16 @@ int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
         struct ia64_tr_entry *p;
         int cpu = smp_processor_id();
 
+        if (!ia64_idtrs[cpu]) {
+                ia64_idtrs[cpu] = kmalloc(2 * IA64_TR_ALLOC_MAX *
+                                sizeof (struct ia64_tr_entry), GFP_KERNEL);
+                if (!ia64_idtrs[cpu])
+                        return -ENOMEM;
+        }
         r = -EINVAL;
         /*Check overlap with existing TR entries*/
         if (target_mask & 0x1) {
-                p = &__per_cpu_idtrs[cpu][0][0];
+                p = ia64_idtrs[cpu];
                 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
                                                                 i++, p++) {
                         if (p->pte & 0x1)
@@ -444,7 +450,7 @@ int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
                 }
         }
         if (target_mask & 0x2) {
-                p = &__per_cpu_idtrs[cpu][1][0];
+                p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX;
                 for (i = IA64_TR_ALLOC_BASE; i <= per_cpu(ia64_tr_used, cpu);
                                                                 i++, p++) {
                         if (p->pte & 0x1)
@@ -459,16 +465,16 @@ int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size)
         for (i = IA64_TR_ALLOC_BASE; i < per_cpu(ia64_tr_num, cpu); i++) {
                 switch (target_mask & 0x3) {
                 case 1:
-                        if (!(__per_cpu_idtrs[cpu][0][i].pte & 0x1))
+                        if (!((ia64_idtrs[cpu] + i)->pte & 0x1))
                                 goto found;
                         continue;
                 case 2:
-                        if (!(__per_cpu_idtrs[cpu][1][i].pte & 0x1))
+                        if (!((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
                                 goto found;
                         continue;
                 case 3:
-                        if (!(__per_cpu_idtrs[cpu][0][i].pte & 0x1) &&
-                                !(__per_cpu_idtrs[cpu][1][i].pte & 0x1))
+                        if (!((ia64_idtrs[cpu] + i)->pte & 0x1) &&
+                            !((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
                                 goto found;
                         continue;
                 default:
@@ -488,7 +494,7 @@ found:
         if (target_mask & 0x1) {
                 ia64_itr(0x1, i, va, pte, log_size);
                 ia64_srlz_i();
-                p = &__per_cpu_idtrs[cpu][0][i];
+                p = ia64_idtrs[cpu] + i;
                 p->ifa = va;
                 p->pte = pte;
                 p->itir = log_size << 2;
@@ -497,7 +503,7 @@ found:
         if (target_mask & 0x2) {
                 ia64_itr(0x2, i, va, pte, log_size);
                 ia64_srlz_i();
-                p = &__per_cpu_idtrs[cpu][1][i];
+                p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i;
                 p->ifa = va;
                 p->pte = pte;
                 p->itir = log_size << 2;
@@ -528,7 +534,7 @@ void ia64_ptr_entry(u64 target_mask, int slot)
                 return;
 
         if (target_mask & 0x1) {
-                p = &__per_cpu_idtrs[cpu][0][slot];
+                p = ia64_idtrs[cpu] + slot;
                 if ((p->pte&0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
                         p->pte = 0;
                         ia64_ptr(0x1, p->ifa, p->itir>>2);
@@ -537,7 +543,7 @@ void ia64_ptr_entry(u64 target_mask, int slot)
         }
 
         if (target_mask & 0x2) {
-                p = &__per_cpu_idtrs[cpu][1][slot];
+                p = ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + slot;
                 if ((p->pte & 0x1) && is_tr_overlap(p, p->ifa, p->itir>>2)) {
                         p->pte = 0;
                         ia64_ptr(0x2, p->ifa, p->itir>>2);
@@ -546,8 +552,8 @@ void ia64_ptr_entry(u64 target_mask, int slot)
         }
 
         for (i = per_cpu(ia64_tr_used, cpu); i >= IA64_TR_ALLOC_BASE; i--) {
-                if ((__per_cpu_idtrs[cpu][0][i].pte & 0x1) ||
-                                (__per_cpu_idtrs[cpu][1][i].pte & 0x1))
+                if (((ia64_idtrs[cpu] + i)->pte & 0x1) ||
+                    ((ia64_idtrs[cpu] + IA64_TR_ALLOC_MAX + i)->pte & 0x1))
                         break;
         }
         per_cpu(ia64_tr_used, cpu) = i;