percpu: clean up percpu variable definitions

Percpu variable definition is about to be updated such that all percpu
symbols including the static ones must be unique.  Update percpu
variable definitions accordingly.

* as,cfq: rename ioc_count uniquely

* cpufreq: rename cpu_dbs_info uniquely

* xen: move nesting_count out of xen_evtchn_do_upcall() and rename it

* mm: move ratelimits out of balance_dirty_pages_ratelimited_nr() and
  rename it

* ipv4,6: rename cookie_scratch uniquely

* x86 perf_counter: rename prev_left to pmc_prev_left, irq_entry to
  pmc_irq_entry and nmi_entry to pmc_nmi_entry

* perf_counter: rename disable_count to perf_disable_count

* ftrace: rename test_event_disable to ftrace_test_event_disable

* kmemleak: rename test_pointer to kmemleak_test_pointer

* mce: rename next_interval to mce_next_interval

[ Impact: percpu usage cleanups, no duplicate static percpu var names ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: linux-mm <linux-mm@kvack.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>

drivers/xen/events.c

@@ -602,6 +602,8 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static DEFINE_PER_CPU(unsigned, xed_nesting_count);
+
 /*
  * Search the CPUs pending events bitmasks.  For each one found, map
  * the event number to an irq, and feed it into do_IRQ() for
@@ -617,7 +619,6 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 	struct pt_regs *old_regs = set_irq_regs(regs);
 	struct shared_info *s = HYPERVISOR_shared_info;
 	struct vcpu_info *vcpu_info = __get_cpu_var(xen_vcpu);
-	static DEFINE_PER_CPU(unsigned, nesting_count);
  	unsigned count;
 
 	exit_idle();
@@ -628,7 +629,7 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 
 		vcpu_info->evtchn_upcall_pending = 0;
 
-		if (__get_cpu_var(nesting_count)++)
+		if (__get_cpu_var(xed_nesting_count)++)
 			goto out;
 
 #ifndef CONFIG_X86 /* No need for a barrier -- XCHG is a barrier on x86. */
@@ -653,8 +654,8 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 
 		BUG_ON(!irqs_disabled());
 
-		count = __get_cpu_var(nesting_count);
-		__get_cpu_var(nesting_count) = 0;
+		count = __get_cpu_var(xed_nesting_count);
+		__get_cpu_var(xed_nesting_count) = 0;
 	} while(count != 1);
 
 out: