[SPARC64]: Fix TLB context allocation with SMT style shared TLBs.
The context allocation scheme we use depends upon there being a 1<-->1
mapping from cpu to physical TLB for correctness. Chips like Niagara
break this assumption.
So what we do is notify all cpus with a cross call when the context
version number changes, and if necessary this makes them allocate
a valid context for the address space they are running at the time.
Stress tested with make -j1024, make -j2048, and make -j4096 kernel
builds on a 32-strand, 8 core, T2000 with 16GB of ram.
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/asm-sparc64/mmu_context.h b/include/asm-sparc64/mmu_context.h
index eb660b1..4be40c5 100644
--- a/include/asm-sparc64/mmu_context.h
+++ b/include/asm-sparc64/mmu_context.h
@@ -19,6 +19,12 @@
extern unsigned long mmu_context_bmap[];
extern void get_new_mmu_context(struct mm_struct *mm);
+#ifdef CONFIG_SMP
+extern void smp_new_mmu_context_version(void);
+#else
+#define smp_new_mmu_context_version() do { } while (0)
+#endif
+
extern int init_new_context(struct task_struct *tsk, struct mm_struct *mm);
extern void destroy_context(struct mm_struct *mm);
@@ -58,21 +64,17 @@
extern void __flush_tlb_mm(unsigned long, unsigned long);
-/* Switch the current MM context. */
+/* Switch the current MM context. Interrupts are disabled. */
static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, struct task_struct *tsk)
{
unsigned long ctx_valid;
int cpu;
- /* Note: page_table_lock is used here to serialize switch_mm
- * and activate_mm, and their calls to get_new_mmu_context.
- * This use of page_table_lock is unrelated to its other uses.
- */
- spin_lock(&mm->page_table_lock);
+ spin_lock(&mm->context.lock);
ctx_valid = CTX_VALID(mm->context);
if (!ctx_valid)
get_new_mmu_context(mm);
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&mm->context.lock);
if (!ctx_valid || (old_mm != mm)) {
load_secondary_context(mm);
@@ -98,19 +100,16 @@
/* Activate a new MM instance for the current task. */
static inline void activate_mm(struct mm_struct *active_mm, struct mm_struct *mm)
{
+ unsigned long flags;
int cpu;
- /* Note: page_table_lock is used here to serialize switch_mm
- * and activate_mm, and their calls to get_new_mmu_context.
- * This use of page_table_lock is unrelated to its other uses.
- */
- spin_lock(&mm->page_table_lock);
+ spin_lock_irqsave(&mm->context.lock, flags);
if (!CTX_VALID(mm->context))
get_new_mmu_context(mm);
cpu = smp_processor_id();
if (!cpu_isset(cpu, mm->cpu_vm_mask))
cpu_set(cpu, mm->cpu_vm_mask);
- spin_unlock(&mm->page_table_lock);
+ spin_unlock_irqrestore(&mm->context.lock, flags);
load_secondary_context(mm);
__flush_tlb_mm(CTX_HWBITS(mm->context), SECONDARY_CONTEXT);