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
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a9e40a2493
@ -21,7 +21,7 @@ config X86
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select HAVE_UNSTABLE_SCHED_CLOCK
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select HAVE_IDE
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select HAVE_OPROFILE
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select HAVE_PERF_EVENTS if (!M386 && !M486)
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select HAVE_PERF_EVENTS
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select HAVE_IRQ_WORK
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select HAVE_IOREMAP_PROT
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select HAVE_KPROBES
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@ -381,6 +381,20 @@ static void release_pmc_hardware(void) {}
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#endif
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static bool check_hw_exists(void)
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{
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u64 val, val_new = 0;
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int ret = 0;
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val = 0xabcdUL;
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ret |= checking_wrmsrl(x86_pmu.perfctr, val);
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ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);
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if (ret || val != val_new)
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return false;
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return true;
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}
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static void reserve_ds_buffers(void);
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static void release_ds_buffers(void);
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@ -1372,6 +1386,12 @@ void __init init_hw_perf_events(void)
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pmu_check_apic();
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/* sanity check that the hardware exists or is emulated */
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if (!check_hw_exists()) {
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pr_cont("Broken PMU hardware detected, software events only.\n");
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return;
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}
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pr_cont("%s PMU driver.\n", x86_pmu.name);
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if (x86_pmu.quirks)
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@ -850,6 +850,7 @@ struct perf_event_context {
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int nr_active;
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int is_active;
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int nr_stat;
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int rotate_disable;
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atomic_t refcount;
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struct task_struct *task;
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@ -908,20 +909,6 @@ extern int perf_num_counters(void);
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extern const char *perf_pmu_name(void);
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extern void __perf_event_task_sched_in(struct task_struct *task);
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extern void __perf_event_task_sched_out(struct task_struct *task, struct task_struct *next);
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extern atomic_t perf_task_events;
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static inline void perf_event_task_sched_in(struct task_struct *task)
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{
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COND_STMT(&perf_task_events, __perf_event_task_sched_in(task));
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}
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static inline
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void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)
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{
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COND_STMT(&perf_task_events, __perf_event_task_sched_out(task, next));
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}
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extern int perf_event_init_task(struct task_struct *child);
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extern void perf_event_exit_task(struct task_struct *child);
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extern void perf_event_free_task(struct task_struct *task);
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@ -1030,6 +1017,21 @@ have_event:
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__perf_sw_event(event_id, nr, nmi, regs, addr);
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}
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extern atomic_t perf_task_events;
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static inline void perf_event_task_sched_in(struct task_struct *task)
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{
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COND_STMT(&perf_task_events, __perf_event_task_sched_in(task));
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}
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static inline
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void perf_event_task_sched_out(struct task_struct *task, struct task_struct *next)
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{
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perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
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COND_STMT(&perf_task_events, __perf_event_task_sched_out(task, next));
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}
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extern void perf_event_mmap(struct vm_area_struct *vma);
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extern struct perf_guest_info_callbacks *perf_guest_cbs;
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extern int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *callbacks);
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@ -1287,8 +1287,6 @@ void __perf_event_task_sched_out(struct task_struct *task,
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{
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int ctxn;
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perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
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for_each_task_context_nr(ctxn)
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perf_event_context_sched_out(task, ctxn, next);
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}
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@ -1622,8 +1620,12 @@ static void rotate_ctx(struct perf_event_context *ctx)
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{
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raw_spin_lock(&ctx->lock);
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/* Rotate the first entry last of non-pinned groups */
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list_rotate_left(&ctx->flexible_groups);
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/*
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* Rotate the first entry last of non-pinned groups. Rotation might be
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* disabled by the inheritance code.
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*/
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if (!ctx->rotate_disable)
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list_rotate_left(&ctx->flexible_groups);
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raw_spin_unlock(&ctx->lock);
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}
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@ -6162,6 +6164,7 @@ int perf_event_init_context(struct task_struct *child, int ctxn)
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struct perf_event *event;
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struct task_struct *parent = current;
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int inherited_all = 1;
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unsigned long flags;
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int ret = 0;
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child->perf_event_ctxp[ctxn] = NULL;
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@ -6202,6 +6205,15 @@ int perf_event_init_context(struct task_struct *child, int ctxn)
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break;
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}
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/*
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* We can't hold ctx->lock when iterating the ->flexible_group list due
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* to allocations, but we need to prevent rotation because
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* rotate_ctx() will change the list from interrupt context.
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*/
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raw_spin_lock_irqsave(&parent_ctx->lock, flags);
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parent_ctx->rotate_disable = 1;
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raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
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list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
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ret = inherit_task_group(event, parent, parent_ctx,
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child, ctxn, &inherited_all);
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@ -6209,6 +6221,10 @@ int perf_event_init_context(struct task_struct *child, int ctxn)
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break;
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}
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raw_spin_lock_irqsave(&parent_ctx->lock, flags);
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parent_ctx->rotate_disable = 0;
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raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
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child_ctx = child->perf_event_ctxp[ctxn];
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if (child_ctx && inherited_all) {
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