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Commit a9e40a24 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-fixes-for-linus' of... 

Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf: Fix the software context switch counter
  perf, x86: Fixup Kconfig deps
  x86, perf, nmi: Disable perf if counters are not accessible
  perf: Fix inherit vs. context rotation bug
parents 75f5d2c9 ee6dcfa4

arch/x86/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -21,7 +21,7 @@ config X86 
	select HAVE_UNSTABLE_SCHED_CLOCK

	select HAVE_IDE

	select HAVE_OPROFILE

	select HAVE_PERF_EVENTS if (!M386 && !M486)

	select HAVE_PERF_EVENTS

	select HAVE_IRQ_WORK

	select HAVE_IOREMAP_PROT

	select HAVE_KPROBES

arch/x86/kernel/cpu/perf_event.c

+20 −0
Original line number Diff line number Diff line
@@ -381,6 +381,20 @@ static void release_pmc_hardware(void) {} 


#endif



static bool check_hw_exists(void)

{

	u64 val, val_new = 0;

	int ret = 0;



	val = 0xabcdUL;

	ret |= checking_wrmsrl(x86_pmu.perfctr, val);

	ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);

	if (ret || val != val_new)

		return false;



	return true;

}



static void reserve_ds_buffers(void);

static void release_ds_buffers(void);
@@ -1372,6 +1386,12 @@ void __init init_hw_perf_events(void) 


	pmu_check_apic();



	/* sanity check that the hardware exists or is emulated */

	if (!check_hw_exists()) {

		pr_cont("Broken PMU hardware detected, software events only.\n");

		return;

	}



	pr_cont("%s PMU driver.\n", x86_pmu.name);



	if (x86_pmu.quirks)

include/linux/perf_event.h

+16 −14
Original line number Diff line number Diff line
@@ -850,6 +850,7 @@ struct perf_event_context { 
	int				nr_active;

	int				is_active;

	int				nr_stat;

	int				rotate_disable;

	atomic_t			refcount;

	struct task_struct		*task;
@@ -908,20 +909,6 @@ extern int perf_num_counters(void); 
extern const char *perf_pmu_name(void);

extern void __perf_event_task_sched_in(struct task_struct *task);

extern void __perf_event_task_sched_out(struct task_struct *task, struct task_struct *next);



extern atomic_t perf_task_events;



static inline void perf_event_task_sched_in(struct task_struct *task)

{

	COND_STMT(&perf_task_events, __perf_event_task_sched_in(task));

}



static inline

void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)

{

	COND_STMT(&perf_task_events, __perf_event_task_sched_out(task, next));

}



extern int perf_event_init_task(struct task_struct *child);

extern void perf_event_exit_task(struct task_struct *child);

extern void perf_event_free_task(struct task_struct *task);
@@ -1030,6 +1017,21 @@ perf_sw_event(u32 event_id, u64 nr, int nmi, struct pt_regs *regs, u64 addr) 
	__perf_sw_event(event_id, nr, nmi, regs, addr);

}



extern atomic_t perf_task_events;



static inline void perf_event_task_sched_in(struct task_struct *task)

{

	COND_STMT(&perf_task_events, __perf_event_task_sched_in(task));

}



static inline

void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)

{

	perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);



	COND_STMT(&perf_task_events, __perf_event_task_sched_out(task, next));

}



extern void perf_event_mmap(struct vm_area_struct *vma);

extern struct perf_guest_info_callbacks *perf_guest_cbs;

extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);

kernel/perf_event.c

+20 −4
Original line number Diff line number Diff line
@@ -1287,8 +1287,6 @@ void __perf_event_task_sched_out(struct task_struct *task, 
{

	int ctxn;



	perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);



	for_each_task_context_nr(ctxn)

		perf_event_context_sched_out(task, ctxn, next);

}
@@ -1622,7 +1620,11 @@ static void rotate_ctx(struct perf_event_context *ctx) 
{

	raw_spin_lock(&ctx->lock);



	/* Rotate the first entry last of non-pinned groups */

	/*

	 * Rotate the first entry last of non-pinned groups. Rotation might be

	 * disabled by the inheritance code.

	 */

	if (!ctx->rotate_disable)

		list_rotate_left(&ctx->flexible_groups);



	raw_spin_unlock(&ctx->lock);
@@ -6162,6 +6164,7 @@ int perf_event_init_context(struct task_struct *child, int ctxn) 
	struct perf_event *event;

	struct task_struct *parent = current;

	int inherited_all = 1;

	unsigned long flags;

	int ret = 0;



	child->perf_event_ctxp[ctxn] = NULL;
@@ -6202,6 +6205,15 @@ int perf_event_init_context(struct task_struct *child, int ctxn) 
			break;

	}



	/*

	 * We can't hold ctx->lock when iterating the ->flexible_group list due

	 * to allocations, but we need to prevent rotation because

	 * rotate_ctx() will change the list from interrupt context.

	 */

	raw_spin_lock_irqsave(&parent_ctx->lock, flags);

	parent_ctx->rotate_disable = 1;

	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);



	list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {

		ret = inherit_task_group(event, parent, parent_ctx,

					 child, ctxn, &inherited_all);
@@ -6209,6 +6221,10 @@ int perf_event_init_context(struct task_struct *child, int ctxn) 
			break;

	}



	raw_spin_lock_irqsave(&parent_ctx->lock, flags);

	parent_ctx->rotate_disable = 0;

	raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);



	child_ctx = child->perf_event_ctxp[ctxn];



	if (child_ctx && inherited_all) {