tracing/boot: Add cpu_mask option support

Add ftrace.cpumask option support to boot-time tracing.
This sets cpumask for each instance.

 - ftrace.[instance.INSTANCE.]cpumask = CPUMASK;
   Set the trace cpumask. Note that the CPUMASK should be a string
   which <tracefs>/tracing_cpumask can accepts.

Link: http://lkml.kernel.org/r/157867243625.17873.13613922641273149372.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 6c996d1b1687ffc611b000cfa6d47201db4cf7c9..106bbc0988feb6be74e9056bc6a3e600a9f8eeb1 100644 (file)
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4561,20 +4561,13 @@ out_err:
        return count;
 }
 
-static ssize_t
-tracing_cpumask_write(struct file *filp, const char __user *ubuf,
-                     size_t count, loff_t *ppos)
+int tracing_set_cpumask(struct trace_array *tr,
+                       cpumask_var_t tracing_cpumask_new)
 {
-       struct trace_array *tr = file_inode(filp)->i_private;
-       cpumask_var_t tracing_cpumask_new;
-       int err, cpu;
-
-       if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
-               return -ENOMEM;
+       int cpu;
 
-       err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
-       if (err)
-               goto err_unlock;
+       if (!tr)
+               return -EINVAL;
 
        local_irq_disable();
        arch_spin_lock(&tr->max_lock);
@@ -4598,11 +4591,34 @@ tracing_cpumask_write(struct file *filp, const char __user *ubuf,
        local_irq_enable();
 
        cpumask_copy(tr->tracing_cpumask, tracing_cpumask_new);
+
+       return 0;
+}
+
+static ssize_t
+tracing_cpumask_write(struct file *filp, const char __user *ubuf,
+                     size_t count, loff_t *ppos)
+{
+       struct trace_array *tr = file_inode(filp)->i_private;
+       cpumask_var_t tracing_cpumask_new;
+       int err;
+
+       if (!alloc_cpumask_var(&tracing_cpumask_new, GFP_KERNEL))
+               return -ENOMEM;
+
+       err = cpumask_parse_user(ubuf, count, tracing_cpumask_new);
+       if (err)
+               goto err_free;
+
+       err = tracing_set_cpumask(tr, tracing_cpumask_new);
+       if (err)
+               goto err_free;
+
        free_cpumask_var(tracing_cpumask_new);
 
        return count;
 
-err_unlock:
+err_free:
        free_cpumask_var(tracing_cpumask_new);
 
        return err;

diff --git a/kernel/trace/trace_boot.c b/kernel/trace/trace_boot.c
index f5db30d25b0b37b3ab29414e5c1c79137ed95564..81d923c16a4d6534f7ee11a1b61fd571e096a928 100644 (file)
--- a/kernel/trace/trace_boot.c
+++ b/kernel/trace/trace_boot.c
@@ -18,6 +18,8 @@ extern int trace_set_options(struct trace_array *tr, char *option);
 extern int tracing_set_tracer(struct trace_array *tr, const char *buf);
 extern ssize_t tracing_resize_ring_buffer(struct trace_array *tr,
                                          unsigned long size, int cpu_id);
+extern int tracing_set_cpumask(struct trace_array *tr,
+                               cpumask_var_t tracing_cpumask_new);
 
 static void __init
 trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
@@ -52,6 +54,18 @@ trace_boot_set_instance_options(struct trace_array *tr, struct xbc_node *node)
                if (tracing_resize_ring_buffer(tr, v, RING_BUFFER_ALL_CPUS) < 0)
                        pr_err("Failed to resize trace buffer to %s\n", p);
        }
+
+       p = xbc_node_find_value(node, "cpumask", NULL);
+       if (p && *p != '\0') {
+               cpumask_var_t new_mask;
+
+               if (alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+                       if (cpumask_parse(p, new_mask) < 0 ||
+                           tracing_set_cpumask(tr, new_mask) < 0)
+                               pr_err("Failed to set new CPU mask %s\n", p);
+                       free_cpumask_var(new_mask);
+               }
+       }
 }
 
 #ifdef CONFIG_EVENT_TRACING