From 95cdd2e7851cce79ab839cb0b3cbe68d7911d0f1 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sun, 21 Dec 2008 13:50:42 +0100 Subject: perfcounters: enable lowlevel pmc code to schedule counters Allow lowlevel ->enable() op to return an error if a counter can not be added. This can be used to handle counter constraints. Signed-off-by: Ingo Molnar --- kernel/perf_counter.c | 62 +++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 45 insertions(+), 17 deletions(-) (limited to 'kernel/perf_counter.c') diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index f1110ac1267b..2e73929a6959 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -355,21 +355,25 @@ void perf_counter_task_sched_out(struct task_struct *task, int cpu) cpuctx->task_ctx = NULL; } -static void +static int counter_sched_in(struct perf_counter *counter, struct perf_cpu_context *cpuctx, struct perf_counter_context *ctx, int cpu) { if (counter->state == PERF_COUNTER_STATE_OFF) - return; + return 0; + + if (counter->hw_ops->enable(counter)) + return -EAGAIN; - counter->hw_ops->enable(counter); counter->state = PERF_COUNTER_STATE_ACTIVE; counter->oncpu = cpu; /* TODO: put 'cpu' into cpuctx->cpu */ cpuctx->active_oncpu++; ctx->nr_active++; + + return 0; } static int @@ -378,20 +382,38 @@ group_sched_in(struct perf_counter *group_counter, struct perf_counter_context *ctx, int cpu) { - struct perf_counter *counter; - int was_group = 0; + struct perf_counter *counter, *partial_group; + int ret = 0; - counter_sched_in(group_counter, cpuctx, ctx, cpu); + if (counter_sched_in(group_counter, cpuctx, ctx, cpu)) + return -EAGAIN; /* * Schedule in siblings as one group (if any): */ list_for_each_entry(counter, &group_counter->sibling_list, list_entry) { - counter_sched_in(counter, cpuctx, ctx, cpu); - was_group = 1; + if (counter_sched_in(counter, cpuctx, ctx, cpu)) { + partial_group = counter; + goto group_error; + } + ret = -EAGAIN; } - return was_group; + return ret; + +group_error: + /* + * Groups can be scheduled in as one unit only, so undo any + * partial group before returning: + */ + list_for_each_entry(counter, &group_counter->sibling_list, list_entry) { + if (counter == partial_group) + break; + counter_sched_out(counter, cpuctx, ctx); + } + counter_sched_out(group_counter, cpuctx, ctx); + + return -EAGAIN; } /* @@ -416,9 +438,6 @@ void perf_counter_task_sched_in(struct task_struct *task, int cpu) spin_lock(&ctx->lock); list_for_each_entry(counter, &ctx->counter_list, list_entry) { - if (ctx->nr_active == cpuctx->max_pertask) - break; - /* * Listen to the 'cpu' scheduling filter constraint * of counters: @@ -856,8 +875,9 @@ static const struct file_operations perf_fops = { .poll = perf_poll, }; -static void cpu_clock_perf_counter_enable(struct perf_counter *counter) +static int cpu_clock_perf_counter_enable(struct perf_counter *counter) { + return 0; } static void cpu_clock_perf_counter_disable(struct perf_counter *counter) @@ -913,11 +933,13 @@ static void task_clock_perf_counter_read(struct perf_counter *counter) task_clock_perf_counter_update(counter, now); } -static void task_clock_perf_counter_enable(struct perf_counter *counter) +static int task_clock_perf_counter_enable(struct perf_counter *counter) { u64 now = task_clock_perf_counter_val(counter, 0); atomic64_set(&counter->hw.prev_count, now); + + return 0; } static void task_clock_perf_counter_disable(struct perf_counter *counter) @@ -960,12 +982,14 @@ static void page_faults_perf_counter_read(struct perf_counter *counter) page_faults_perf_counter_update(counter); } -static void page_faults_perf_counter_enable(struct perf_counter *counter) +static int page_faults_perf_counter_enable(struct perf_counter *counter) { /* * page-faults is a per-task value already, * so we dont have to clear it on switch-in. */ + + return 0; } static void page_faults_perf_counter_disable(struct perf_counter *counter) @@ -1006,12 +1030,14 @@ static void context_switches_perf_counter_read(struct perf_counter *counter) context_switches_perf_counter_update(counter); } -static void context_switches_perf_counter_enable(struct perf_counter *counter) +static int context_switches_perf_counter_enable(struct perf_counter *counter) { /* * ->nvcsw + curr->nivcsw is a per-task value already, * so we dont have to clear it on switch-in. */ + + return 0; } static void context_switches_perf_counter_disable(struct perf_counter *counter) @@ -1050,12 +1076,14 @@ static void cpu_migrations_perf_counter_read(struct perf_counter *counter) cpu_migrations_perf_counter_update(counter); } -static void cpu_migrations_perf_counter_enable(struct perf_counter *counter) +static int cpu_migrations_perf_counter_enable(struct perf_counter *counter) { /* * se.nr_migrations is a per-task value already, * so we dont have to clear it on switch-in. */ + + return 0; } static void cpu_migrations_perf_counter_disable(struct perf_counter *counter) -- cgit v1.2.2