cpumask: convert kernel trace functions

Impact: Reduce future memory usage, use new cpumask API.

(Eventually, cpumask_var_t will be allocated based on nr_cpu_ids, not NR_CPUS).

Convert kernel trace functions to use struct cpumask API:
1) Use cpumask_copy/cpumask_test_cpu/for_each_cpu.
2) Use cpumask_var_t and alloc_cpumask_var/free_cpumask_var everywhere.
3) Use on_each_cpu instead of playing with current->cpus_allowed.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>

3 files changed, 64 insertions, 51 deletions

diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 1d601a7c4587..a9d9760dc7b6 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -195,7 +195,7 @@ void *ring_buffer_event_data(struct ring_buffer_event *event)
 EXPORT_SYMBOL_GPL(ring_buffer_event_data);
 
 #define for_each_buffer_cpu(buffer, cpu)                \
-        for_each_cpu_mask(cpu, buffer->cpumask)
+        for_each_cpu(cpu, buffer->cpumask)
 
 #define TS_SHIFT        27
 #define TS_MASK         ((1ULL << TS_SHIFT) - 1)
@@ -267,7 +267,7 @@ struct ring_buffer {
         unsigned                        pages;
         unsigned                        flags;
         int                             cpus;
-        cpumask_t                       cpumask;
+        cpumask_var_t                   cpumask;
         atomic_t                        record_disabled;
 
         struct mutex                    mutex;
@@ -458,6 +458,9 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
         if (!buffer)
                 return NULL;
 
+        if (!alloc_cpumask_var(&buffer->cpumask, GFP_KERNEL))
+                goto fail_free_buffer;
+
         buffer->pages = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
         buffer->flags = flags;
 
@@ -465,14 +468,14 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
         if (buffer->pages == 1)
                 buffer->pages++;
 
-        buffer->cpumask = cpu_possible_map;
+        cpumask_copy(buffer->cpumask, cpu_possible_mask);
         buffer->cpus = nr_cpu_ids;
 
         bsize = sizeof(void *) * nr_cpu_ids;
         buffer->buffers = kzalloc(ALIGN(bsize, cache_line_size()),
                                   GFP_KERNEL);
         if (!buffer->buffers)
-                goto fail_free_buffer;
+                goto fail_free_cpumask;
 
         for_each_buffer_cpu(buffer, cpu) {
                 buffer->buffers[cpu] =
@@ -492,6 +495,9 @@ struct ring_buffer *ring_buffer_alloc(unsigned long size, unsigned flags)
         }
         kfree(buffer->buffers);
 
+ fail_free_cpumask:
+        free_cpumask_var(buffer->cpumask);
+
  fail_free_buffer:
         kfree(buffer);
         return NULL;
@@ -510,6 +516,8 @@ ring_buffer_free(struct ring_buffer *buffer)
         for_each_buffer_cpu(buffer, cpu)
                 rb_free_cpu_buffer(buffer->buffers[cpu]);
 
+        free_cpumask_var(buffer->cpumask);
+
         kfree(buffer);
 }
 EXPORT_SYMBOL_GPL(ring_buffer_free);
@@ -1283,7 +1291,7 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer,
 
         cpu = raw_smp_processor_id();
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 goto out;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -1396,7 +1404,7 @@ int ring_buffer_write(struct ring_buffer *buffer,
 
         cpu = raw_smp_processor_id();
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 goto out;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -1478,7 +1486,7 @@ void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -1498,7 +1506,7 @@ void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -1515,7 +1523,7 @@ unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return 0;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -1532,7 +1540,7 @@ unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return 0;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -1850,7 +1858,7 @@ rb_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts)
         struct buffer_page *reader;
         int nr_loops = 0;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return NULL;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -2025,7 +2033,7 @@ ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts)
         struct ring_buffer_event *event;
         unsigned long flags;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return NULL;
 
         spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
@@ -2062,7 +2070,7 @@ ring_buffer_read_start(struct ring_buffer *buffer, int cpu)
         struct ring_buffer_iter *iter;
         unsigned long flags;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return NULL;
 
         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
@@ -2172,7 +2180,7 @@ void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu)
         struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
         unsigned long flags;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return;
 
         spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
@@ -2228,7 +2236,7 @@ int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu)
 {
         struct ring_buffer_per_cpu *cpu_buffer;
 
-        if (!cpu_isset(cpu, buffer->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer->cpumask))
                 return 1;
 
         cpu_buffer = buffer->buffers[cpu];
@@ -2252,8 +2260,8 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
         struct ring_buffer_per_cpu *cpu_buffer_a;
         struct ring_buffer_per_cpu *cpu_buffer_b;
 
-        if (!cpu_isset(cpu, buffer_a->cpumask) ||
-            !cpu_isset(cpu, buffer_b->cpumask))
+        if (!cpumask_test_cpu(cpu, buffer_a->cpumask) ||
+            !cpumask_test_cpu(cpu, buffer_b->cpumask))
                 return -EINVAL;
 
         /* At least make sure the two buffers are somewhat the same */
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0e91f43b6baf..5d04e27f3b40 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -89,10 +89,10 @@ static inline void ftrace_enable_cpu(void)
         preempt_enable();
 }
 
-static cpumask_t __read_mostly          tracing_buffer_mask;
+static cpumask_var_t __read_mostly      tracing_buffer_mask;
 
 #define for_each_tracing_cpu(cpu)       \
-        for_each_cpu_mask(cpu, tracing_buffer_mask)
+        for_each_cpu(cpu, tracing_buffer_mask)
 
 /*
  * ftrace_dump_on_oops - variable to dump ftrace buffer on oops
@@ -2646,13 +2646,7 @@ static struct file_operations show_traces_fops = {
 /*
  * Only trace on a CPU if the bitmask is set:
  */
-static cpumask_t tracing_cpumask = CPU_MASK_ALL;
-
-/*
- * When tracing/tracing_cpu_mask is modified then this holds
- * the new bitmask we are about to install:
- */
-static cpumask_t tracing_cpumask_new;
+static cpumask_var_t tracing_cpumask;
 
 /*
  * The tracer itself will not take this lock, but still we want
@@ -2674,7 +2668,7 @@ tracing_cpumask_read(struct file *filp, char __user *ubuf,
 
         mutex_lock(&tracing_cpumask_update_lock);
 
-        len = cpumask_scnprintf(mask_str, count, &tracing_cpumask);
+        len = cpumask_scnprintf(mask_str, count, tracing_cpumask);
         if (count - len < 2) {
                 count = -EINVAL;
                 goto out_err;
@@ -2693,9 +2687,13 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
                       size_t count, loff_t *ppos)
 {
         int err, cpu;
+        cpumask_var_t tracing_cpumask_new;
+
+        if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+                return -ENOMEM;
 
         mutex_lock(&tracing_cpumask_update_lock);
-        err = cpumask_parse_user(ubuf, count, &tracing_cpumask_new);
+        err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
         if (err)
                 goto err_unlock;
 
@@ -2706,26 +2704,28 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
                  * Increase/decrease the disabled counter if we are
                  * about to flip a bit in the cpumask:
                  */
-                if (cpu_isset(cpu, tracing_cpumask) &&
-                                !cpu_isset(cpu, tracing_cpumask_new)) {
+                if (cpumask_test_cpu(cpu, tracing_cpumask) &&
+                                !cpumask_test_cpu(cpu, tracing_cpumask_new)) {
                         atomic_inc(&global_trace.data[cpu]->disabled);
                 }
-                if (!cpu_isset(cpu, tracing_cpumask) &&
-                                cpu_isset(cpu, tracing_cpumask_new)) {
+                if (!cpumask_test_cpu(cpu, tracing_cpumask) &&
+                                cpumask_test_cpu(cpu, tracing_cpumask_new)) {
                         atomic_dec(&global_trace.data[cpu]->disabled);
                 }
         }
         __raw_spin_unlock(&ftrace_max_lock);
         local_irq_enable();
 
-        tracing_cpumask = tracing_cpumask_new;
+        cpumask_copy(tracing_cpumask, tracing_cpumask_new);
 
         mutex_unlock(&tracing_cpumask_update_lock);
+        free_cpumask_var(tracing_cpumask_new);
 
         return count;
 
 err_unlock:
         mutex_unlock(&tracing_cpumask_update_lock);
+        free_cpumask_var(tracing_cpumask);
 
         return err;
 }
@@ -3752,7 +3752,6 @@ void ftrace_dump(void)
         static DEFINE_SPINLOCK(ftrace_dump_lock);
         /* use static because iter can be a bit big for the stack */
         static struct trace_iterator iter;
-        static cpumask_t mask;
         static int dump_ran;
         unsigned long flags;
         int cnt = 0, cpu;
@@ -3786,8 +3785,6 @@ void ftrace_dump(void)
          * and then release the locks again.
          */
 
-        cpus_clear(mask);
-
         while (!trace_empty(&iter)) {
 
                 if (!cnt)
@@ -3823,19 +3820,28 @@ __init static int tracer_alloc_buffers(void)
 {
         struct trace_array_cpu *data;
         int i;
+        int ret = -ENOMEM;
 
-        /* TODO: make the number of buffers hot pluggable with CPUS */
-        tracing_buffer_mask = cpu_possible_map;
+        if (!alloc_cpumask_var(&tracing_buffer_mask, GFP_KERNEL))
+                goto out;
+
+        if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL))
+                goto out_free_buffer_mask;
 
+        cpumask_copy(tracing_buffer_mask, cpu_possible_mask);
+        cpumask_copy(tracing_cpumask, cpu_all_mask);
+
+        /* TODO: make the number of buffers hot pluggable with CPUS */
         global_trace.buffer = ring_buffer_alloc(trace_buf_size,
                                                    TRACE_BUFFER_FLAGS);
         if (!global_trace.buffer) {
                 printk(KERN_ERR "tracer: failed to allocate ring buffer!\n");
                 WARN_ON(1);
-                return 0;
+                goto out_free_cpumask;
         }
         global_trace.entries = ring_buffer_size(global_trace.buffer);
 
+
 #ifdef CONFIG_TRACER_MAX_TRACE
         max_tr.buffer = ring_buffer_alloc(trace_buf_size,
                                              TRACE_BUFFER_FLAGS);
@@ -3843,7 +3849,7 @@ __init static int tracer_alloc_buffers(void)
                 printk(KERN_ERR "tracer: failed to allocate max ring buffer!\n");
                 WARN_ON(1);
                 ring_buffer_free(global_trace.buffer);
-                return 0;
+                goto out_free_cpumask;
         }
         max_tr.entries = ring_buffer_size(max_tr.buffer);
         WARN_ON(max_tr.entries != global_trace.entries);
@@ -3873,8 +3879,14 @@ __init static int tracer_alloc_buffers(void)
                                        &trace_panic_notifier);
 
         register_die_notifier(&trace_die_notifier);
+        ret = 0;
 
-        return 0;
+out_free_cpumask:
+        free_cpumask_var(tracing_cpumask);
+out_free_buffer_mask:
+        free_cpumask_var(tracing_buffer_mask);
+out:
+        return ret;
 }
 early_initcall(tracer_alloc_buffers);
 fs_initcall(tracer_init_debugfs);
diff --git a/kernel/trace/trace_sysprof.c b/kernel/trace/trace_sysprof.c
index a5779bd975db..eaca5ad803ff 100644
--- a/kernel/trace/trace_sysprof.c
+++ b/kernel/trace/trace_sysprof.c
@@ -196,9 +196,9 @@ static enum hrtimer_restart stack_trace_timer_fn(struct hrtimer *hrtimer)
         return HRTIMER_RESTART;
 }
 
-static void start_stack_timer(int cpu)
+static void start_stack_timer(void *unused)
 {
-        struct hrtimer *hrtimer = &per_cpu(stack_trace_hrtimer, cpu);
+        struct hrtimer *hrtimer = &__get_cpu_var(stack_trace_hrtimer);
 
         hrtimer_init(hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
         hrtimer->function = stack_trace_timer_fn;
@@ -208,14 +208,7 @@ static void start_stack_timer(int cpu)
 
 static void start_stack_timers(void)
 {
-        cpumask_t saved_mask = current->cpus_allowed;
-        int cpu;
-
-        for_each_online_cpu(cpu) {
-                set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
-                start_stack_timer(cpu);
-        }
-        set_cpus_allowed_ptr(current, &saved_mask);
+        on_each_cpu(start_stack_timer, NULL, 1);
 }
 
 static void stop_stack_timer(int cpu)