ftrace: modulize the number of CPU buffers

[linux-block.git] / kernel / trace / trace.c

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 290e9da7aa9aedb5edbe10fa95f6d60bb55e9d45..5da391c5fb0dc25a3e0ccf75460a22046d0b0c62 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -35,6 +35,12 @@
 unsigned long __read_mostly    tracing_max_latency = (cycle_t)ULONG_MAX;
 unsigned long __read_mostly    tracing_thresh;
 
+static unsigned long __read_mostly     tracing_nr_buffers;
+static cpumask_t __read_mostly         tracing_buffer_mask;
+
+#define for_each_tracing_cpu(cpu)      \
+       for_each_cpu_mask(cpu, tracing_buffer_mask)
+
 /* dummy trace to disable tracing */
 static struct tracer no_tracer __read_mostly = {
        .name           = "none",
@@ -328,7 +334,7 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu)
        WARN_ON_ONCE(!irqs_disabled());
        __raw_spin_lock(&ftrace_max_lock);
        /* clear out all the previous traces */
-       for_each_possible_cpu(i) {
+       for_each_tracing_cpu(i) {
                data = tr->data[i];
                flip_trace(max_tr.data[i], data);
                tracing_reset(data);
@@ -352,7 +358,7 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
 
        WARN_ON_ONCE(!irqs_disabled());
        __raw_spin_lock(&ftrace_max_lock);
-       for_each_possible_cpu(i)
+       for_each_tracing_cpu(i)
                tracing_reset(max_tr.data[i]);
 
        flip_trace(max_tr.data[cpu], data);
@@ -398,7 +404,7 @@ int register_tracer(struct tracer *type)
                 * internal tracing to verify that everything is in order.
                 * If we fail, we do not register this tracer.
                 */
-               for_each_possible_cpu(i) {
+               for_each_tracing_cpu(i) {
                        data = tr->data[i];
                        if (!head_page(data))
                                continue;
@@ -417,7 +423,7 @@ int register_tracer(struct tracer *type)
                        goto out;
                }
                /* Only reset on passing, to avoid touching corrupted buffers */
-               for_each_possible_cpu(i) {
+               for_each_tracing_cpu(i) {
                        data = tr->data[i];
                        if (!head_page(data))
                                continue;
@@ -847,7 +853,7 @@ find_next_entry(struct trace_iterator *iter, int *ent_cpu)
        int next_cpu = -1;
        int cpu;
 
-       for_each_possible_cpu(cpu) {
+       for_each_tracing_cpu(cpu) {
                if (!head_page(tr->data[cpu]))
                        continue;
                ent = trace_entry_idx(tr, tr->data[cpu], iter, cpu);
@@ -972,7 +978,7 @@ static void *s_start(struct seq_file *m, loff_t *pos)
                iter->prev_ent = NULL;
                iter->prev_cpu = -1;
 
-               for_each_possible_cpu(i) {
+               for_each_tracing_cpu(i) {
                        iter->next_idx[i] = 0;
                        iter->next_page[i] = NULL;
                }
@@ -1089,7 +1095,7 @@ print_trace_header(struct seq_file *m, struct trace_iterator *iter)
        if (type)
                name = type->name;
 
-       for_each_possible_cpu(cpu) {
+       for_each_tracing_cpu(cpu) {
                if (head_page(tr->data[cpu])) {
                        total += tr->data[cpu]->trace_idx;
                        if (tr->data[cpu]->trace_idx > tr->entries)
@@ -1519,7 +1525,7 @@ static int trace_empty(struct trace_iterator *iter)
        struct trace_array_cpu *data;
        int cpu;
 
-       for_each_possible_cpu(cpu) {
+       for_each_tracing_cpu(cpu) {
                data = iter->tr->data[cpu];
 
                if (head_page(data) && data->trace_idx &&
@@ -1831,7 +1837,7 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
 
        raw_local_irq_disable();
        __raw_spin_lock(&ftrace_max_lock);
-       for_each_possible_cpu(cpu) {
+       for_each_tracing_cpu(cpu) {
                /*
                 * Increase/decrease the disabled counter if we are
                 * about to flip a bit in the cpumask:
@@ -2308,7 +2314,7 @@ tracing_read_pipe(struct file *filp, char __user *ubuf,
        ftrace_enabled = 0;
 #endif
        smp_wmb();
-       for_each_possible_cpu(cpu) {
+       for_each_tracing_cpu(cpu) {
                data = iter->tr->data[cpu];
 
                if (!head_page(data) || !data->trace_idx)
@@ -2605,7 +2611,7 @@ static int trace_alloc_page(void)
        int i;
 
        /* first allocate a page for each CPU */
-       for_each_possible_cpu(i) {
+       for_each_tracing_cpu(i) {
                array = (void *)__get_free_page(GFP_KERNEL);
                if (array == NULL) {
                        printk(KERN_ERR "tracer: failed to allocate page"
@@ -2630,7 +2636,7 @@ static int trace_alloc_page(void)
        }
 
        /* Now that we successfully allocate a page per CPU, add them */
-       for_each_possible_cpu(i) {
+       for_each_tracing_cpu(i) {
                data = global_trace.data[i];
                page = list_entry(pages.next, struct page, lru);
                list_del_init(&page->lru);
@@ -2666,7 +2672,7 @@ static int trace_free_page(void)
        int ret = 0;
 
        /* free one page from each buffer */
-       for_each_possible_cpu(i) {
+       for_each_tracing_cpu(i) {
                data = global_trace.data[i];
                p = data->trace_pages.next;
                if (p == &data->trace_pages) {
@@ -2717,8 +2723,12 @@ __init static int tracer_alloc_buffers(void)
 
        global_trace.ctrl = tracer_enabled;
 
+       /* TODO: make the number of buffers hot pluggable with CPUS */
+       tracing_nr_buffers = num_possible_cpus();
+       tracing_buffer_mask = cpu_possible_map;
+
        /* Allocate the first page for all buffers */
-       for_each_possible_cpu(i) {
+       for_each_tracing_cpu(i) {
                data = global_trace.data[i] = &per_cpu(global_trace_cpu, i);
                max_tr.data[i] = &per_cpu(max_data, i);