#include <linux/init.h>
#include <linux/mm.h>
-#include <linux/irq.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/smp_lock.h>
#include <asm/mmu_context.h>
#include <asm/proto.h>
#include <asm/apicdef.h>
+#include <asm/idle.h>
/*
* Smarter SMP flushing macros.
* 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();
- clear_bit(cpu, &read_pda(active_mm)->cpu_vm_mask);
+ cpu_clear(cpu, read_pda(active_mm)->cpu_vm_mask);
load_cr3(swapper_pg_dir);
}
* [cpu0: the cpu that switches]
* 1) switch_mm() either 1a) or 1b)
* 1a) thread switch to a different mm
- * 1a1) clear_bit(cpu, &old_mm->cpu_vm_mask);
+ * 1a1) cpu_clear(cpu, old_mm->cpu_vm_mask);
* Stop ipi delivery for the old mm. This is not synchronized with
* the other cpus, but smp_invalidate_interrupt ignore flush ipis
* for the wrong mm, and in the worst case we perform a superfluous
* was in lazy tlb mode.
* 1a3) update cpu active_mm
* Now cpu0 accepts tlb flushes for the new mm.
- * 1a4) set_bit(cpu, &new_mm->cpu_vm_mask);
+ * 1a4) cpu_set(cpu, new_mm->cpu_vm_mask);
* Now the other cpus will send tlb flush ipis.
* 1a4) change cr3.
* 1b) thread switch without mm change
*
* 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);
}
- ack_APIC_irq();
- cpu_clear(cpu, flush_cpumask);
-
out:
- put_cpu_no_resched();
+ ack_APIC_irq();
+ 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)
{
on_each_cpu(do_flush_tlb_all, NULL, 1, 1);
}
-void smp_kdb_stop(void)
-{
- send_IPI_allbutself(KDB_VECTOR);
-}
-
/*
* this function sends a 'reschedule' IPI to another CPU.
* it goes straight through and wastes no time serializing
static struct call_data_struct * call_data;
+void lock_ipi_call_lock(void)
+{
+ spin_lock_irq(&call_lock);
+}
+
+void unlock_ipi_call_lock(void)
+{
+ spin_unlock_irq(&call_lock);
+}
+
+/*
+ * this function sends a 'generic call function' IPI to one other CPU
+ * in the system.
+ *
+ * cpu is a standard Linux logical CPU number.
+ */
+static void
+__smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+ int nonatomic, int wait)
+{
+ struct call_data_struct data;
+ int cpus = 1;
+
+ data.func = func;
+ data.info = info;
+ atomic_set(&data.started, 0);
+ data.wait = wait;
+ if (wait)
+ atomic_set(&data.finished, 0);
+
+ call_data = &data;
+ wmb();
+ /* Send a message to all other CPUs and wait for them to respond */
+ send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
+
+ /* Wait for response */
+ while (atomic_read(&data.started) != cpus)
+ cpu_relax();
+
+ if (!wait)
+ return;
+
+ while (atomic_read(&data.finished) != cpus)
+ cpu_relax();
+}
+
+/*
+ * smp_call_function_single - Run a function on another CPU
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: Currently unused.
+ * @wait: If true, wait until function has completed on other CPUs.
+ *
+ * Retrurns 0 on success, else a negative status code.
+ *
+ * Does not return until the remote CPU is nearly ready to execute <func>
+ * or is or has executed.
+ */
+
+int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
+ int nonatomic, int wait)
+{
+ /* prevent preemption and reschedule on another processor */
+ int me = get_cpu();
+ if (cpu == me) {
+ WARN_ON(1);
+ put_cpu();
+ return -EBUSY;
+ }
+ spin_lock_bh(&call_lock);
+ __smp_call_function_single(cpu, func, info, nonatomic, wait);
+ spin_unlock_bh(&call_lock);
+ put_cpu();
+ return 0;
+}
+
/*
* this function sends a 'generic call function' IPI to all other CPUs
* in the system.
void smp_stop_cpu(void)
{
+ unsigned long flags;
/*
* Remove this CPU:
*/
cpu_clear(smp_processor_id(), cpu_online_map);
- local_irq_disable();
+ local_irq_save(flags);
disable_local_APIC();
- local_irq_enable();
+ local_irq_restore(flags);
}
static void smp_really_stop_cpu(void *dummy)
/*
* At this point the info structure may be out of scope unless wait==1
*/
+ exit_idle();
irq_enter();
(*func)(info);
irq_exit();
git://git.onelab.eu / linux-2.6.git / blobdiff