__per_cpu_idtrs is statically allocated ... on CONFIG_NR_CPUS=4096
systems it takes 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@xxxxxxxxx>
---
Bjorn found that he couldn't boot a kernel with a few extra drivers
compiled statically. Further digging showed that the problem was
the kernel was too big (max size is controlled by KERNEL_TR_PAGE_SHIFT
in <asm/pgtable.h> ... currently set to 64MB).
More digging showed that on a CONFIG_NR_CPUS=4096 kernel a full quarter
of the available kernel space is used by "__per_cpu_idtrs".
diff --git a/arch/ia64/include/asm/tlb.h b/arch/ia64/include/asm/tlb.h
index 85d965c..23cce99 100644
--- a/arch/ia64/include/asm/tlb.h
+++ b/arch/ia64/include/asm/tlb.h
@@ -74,7 +74,7 @@ struct ia64_tr_entry {
extern int ia64_itr_entry(u64 target_mask, u64 va, u64 pte, u64 log_size);
extern void ia64_ptr_entry(u64 target_mask, int slot);
-extern struct ia64_tr_entry __per_cpu_idtrs[NR_CPUS][2][IA64_TR_ALLOC_MAX];
+extern struct ia64_tr_entry *ia64_idtrs[NR_CPUS];
/*
region register macros
diff --git a/arch/ia64/kernel/mca.c b/arch/ia64/kernel/mca.c
index 32f2639..378b483 100644
--- a/arch/ia64/kernel/mca.c
+++ b/arch/ia64/kernel/mca.c
@@ -1225,9 +1225,12 @@ static void mca_insert_tr(u64 iord)
unsigned long psr;
int cpu = smp_processor_id();
+ if (!ia64_idtrs[cpu])
+ return;
+
psr = ia64_clear_ic();
for (i = IA64_TR_ALLOC_BASE; i < IA64_TR_ALLOC_MAX; i++) {
- p = &__per_cpu_idtrs[cpu][iord-1][i];
+ p = ia64_idtrs[cpu] + (iord - 1) * IA64_TR_ALLOC_MAX;
if (p->pte & 0x1) {
old_rr = ia64_get_rr(p->ifa);
if (old_rr != p->rr) {
diff --git a/arch/ia64/mm/tlb.c b/arch/ia64/mm/tlb.c
index ee09d26..00914da 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] + i;
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 + i;
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;
--
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