#include <asm/proto.h>
#include <asm/apicdef.h>
+#define __cpuinit __init
+
/*
* Smarter SMP flushing macros.
* c/o Linus Torvalds.
* writing to user space from interrupts. (Its not allowed anyway).
*
* Optimizations Manfred Spraul <manfred@colorfullife.com>
+ *
+ * More scalable flush, from Andi Kleen
+ *
+ * To avoid global state use 8 different call vectors.
+ * Each CPU uses a specific vector to trigger flushes on other
+ * CPUs. Depending on the received vector the target CPUs look into
+ * the right per cpu variable for the flush data.
+ *
+ * With more than 8 CPUs they are hashed to the 8 available
+ * vectors. The limited global vector space forces us to this right now.
+ * In future when interrupts are split into per CPU domains this could be
+ * fixed, at the cost of triggering multiple IPIs in some cases.
*/
-static cpumask_t flush_cpumask;
-static struct mm_struct * flush_mm;
-static unsigned long flush_va;
-static DEFINE_SPINLOCK(tlbstate_lock);
+union smp_flush_state {
+ struct {
+ cpumask_t flush_cpumask;
+ struct mm_struct *flush_mm;
+ unsigned long flush_va;
#define FLUSH_ALL -1ULL
+ spinlock_t tlbstate_lock;
+ };
+ char pad[SMP_CACHE_BYTES];
+} ____cacheline_aligned;
+
+/* State is put into the per CPU data section, but padded
+ to a full cache line because other CPUs can access it and we don't
+ want false sharing in the per cpu data segment. */
+static DEFINE_PER_CPU(union smp_flush_state, flush_state);
/*
* We cannot call mmdrop() because we are in interrupt context,
* instead update mm->cpu_vm_mask.
*/
-static inline void leave_mm (unsigned long cpu)
+static inline void leave_mm(int cpu)
{
if (read_pda(mmu_state) == TLBSTATE_OK)
BUG();
*
* 1) Flush the tlb entries if the cpu uses the mm that's being flushed.
* 2) Leave the mm if we are in the lazy tlb mode.
+ *
+ * Interrupts are disabled.
*/
-asmlinkage void smp_invalidate_interrupt (void)
+asmlinkage void smp_invalidate_interrupt(struct pt_regs *regs)
{
- unsigned long cpu;
+ int cpu;
+ int sender;
+ union smp_flush_state *f;
- cpu = get_cpu();
+ cpu = smp_processor_id();
+ /*
+ * orig_rax contains the interrupt vector - 256.
+ * Use that to determine where the sender put the data.
+ */
+ sender = regs->orig_rax + 256 - INVALIDATE_TLB_VECTOR_START;
+ f = &per_cpu(flush_state, sender);
- if (!cpu_isset(cpu, flush_cpumask))
+ if (!cpu_isset(cpu, f->flush_cpumask))
goto out;
/*
* This was a BUG() but until someone can quote me the
* BUG();
*/
- if (flush_mm == read_pda(active_mm)) {
+ if (f->flush_mm == read_pda(active_mm)) {
if (read_pda(mmu_state) == TLBSTATE_OK) {
- if (flush_va == FLUSH_ALL)
+ if (f->flush_va == FLUSH_ALL)
local_flush_tlb();
else
- __flush_tlb_one(flush_va);
+ __flush_tlb_one(f->flush_va);
} else
leave_mm(cpu);
}
out:
ack_APIC_irq();
- cpu_clear(cpu, flush_cpumask);
- put_cpu_no_resched();
+ cpu_clear(cpu, f->flush_cpumask);
}
static void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
unsigned long va)
{
- cpumask_t tmp;
- /*
- * A couple of (to be removed) sanity checks:
- *
- * - we do not send IPIs to not-yet booted CPUs.
- * - current CPU must not be in mask
- * - mask must exist :)
- */
- BUG_ON(cpus_empty(cpumask));
- cpus_and(tmp, cpumask, cpu_online_map);
- BUG_ON(!cpus_equal(tmp, cpumask));
- BUG_ON(cpu_isset(smp_processor_id(), cpumask));
- if (!mm)
- BUG();
+ int sender;
+ union smp_flush_state *f;
- /*
- * I'm not happy about this global shared spinlock in the
- * MM hot path, but we'll see how contended it is.
- * Temporarily this turns IRQs off, so that lockups are
- * detected by the NMI watchdog.
- */
- spin_lock(&tlbstate_lock);
-
- flush_mm = mm;
- flush_va = va;
- cpus_or(flush_cpumask, cpumask, flush_cpumask);
+ /* Caller has disabled preemption */
+ sender = smp_processor_id() % NUM_INVALIDATE_TLB_VECTORS;
+ f = &per_cpu(flush_state, sender);
+
+ /* Could avoid this lock when
+ num_online_cpus() <= NUM_INVALIDATE_TLB_VECTORS, but it is
+ probably not worth checking this for a cache-hot lock. */
+ spin_lock(&f->tlbstate_lock);
+
+ f->flush_mm = mm;
+ f->flush_va = va;
+ cpus_or(f->flush_cpumask, cpumask, f->flush_cpumask);
/*
* We have to send the IPI only to
* CPUs affected.
*/
- send_IPI_mask(cpumask, INVALIDATE_TLB_VECTOR);
+ send_IPI_mask(cpumask, INVALIDATE_TLB_VECTOR_START + sender);
- while (!cpus_empty(flush_cpumask))
- mb(); /* nothing. lockup detection does not belong here */;
+ while (!cpus_empty(f->flush_cpumask))
+ cpu_relax();
- flush_mm = NULL;
- flush_va = 0;
- spin_unlock(&tlbstate_lock);
+ f->flush_mm = NULL;
+ f->flush_va = 0;
+ spin_unlock(&f->tlbstate_lock);
}
+
+int __cpuinit init_smp_flush(void)
+{
+ int i;
+ for_each_cpu_mask(i, cpu_possible_map) {
+ spin_lock_init(&per_cpu(flush_state.tlbstate_lock, i));
+ }
+ return 0;
+}
+
+core_initcall(init_smp_flush);
void flush_tlb_current_task(void)
{
git.openpandora.org / pandora-kernel.git / blobdiff