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author | Jiri Kosina <jkosina@suse.cz> | 2010-04-23 00:08:44 (GMT) |
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committer | Jiri Kosina <jkosina@suse.cz> | 2010-04-23 00:08:44 (GMT) |
commit | 6c9468e9eb1252eaefd94ce7f06e1be9b0b641b1 (patch) | |
tree | 797676a336b050bfa1ef879377c07e541b9075d6 /kernel/trace/ftrace.c | |
parent | 4cb3ca7cd7e2cae8d1daf5345ec99a1e8502cf3f (diff) | |
parent | c81eddb0e3728661d1585fbc564449c94165cc36 (diff) | |
download | linux-fsl-qoriq-6c9468e9eb1252eaefd94ce7f06e1be9b0b641b1.tar.xz |
Merge branch 'master' into for-next
Diffstat (limited to 'kernel/trace/ftrace.c')
-rw-r--r-- | kernel/trace/ftrace.c | 31 |
1 files changed, 17 insertions, 14 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 8378357..2404b59 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -24,9 +24,11 @@ #include <linux/uaccess.h> #include <linux/ftrace.h> #include <linux/sysctl.h> +#include <linux/slab.h> #include <linux/ctype.h> #include <linux/list.h> #include <linux/hash.h> +#include <linux/rcupdate.h> #include <trace/events/sched.h> @@ -84,22 +86,22 @@ ftrace_func_t ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t __ftrace_trace_function __read_mostly = ftrace_stub; ftrace_func_t ftrace_pid_function __read_mostly = ftrace_stub; -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -static int ftrace_set_func(unsigned long *array, int *idx, char *buffer); -#endif - +/* + * Traverse the ftrace_list, invoking all entries. The reason that we + * can use rcu_dereference_raw() is that elements removed from this list + * are simply leaked, so there is no need to interact with a grace-period + * mechanism. The rcu_dereference_raw() calls are needed to handle + * concurrent insertions into the ftrace_list. + * + * Silly Alpha and silly pointer-speculation compiler optimizations! + */ static void ftrace_list_func(unsigned long ip, unsigned long parent_ip) { - struct ftrace_ops *op = ftrace_list; - - /* in case someone actually ports this to alpha! */ - read_barrier_depends(); + struct ftrace_ops *op = rcu_dereference_raw(ftrace_list); /*see above*/ while (op != &ftrace_list_end) { - /* silly alpha */ - read_barrier_depends(); op->func(ip, parent_ip); - op = op->next; + op = rcu_dereference_raw(op->next); /*see above*/ }; } @@ -154,8 +156,7 @@ static int __register_ftrace_function(struct ftrace_ops *ops) * the ops->next pointer is valid before another CPU sees * the ops pointer included into the ftrace_list. */ - smp_wmb(); - ftrace_list = ops; + rcu_assign_pointer(ftrace_list, ops); if (ftrace_enabled) { ftrace_func_t func; @@ -2276,6 +2277,8 @@ __setup("ftrace_filter=", set_ftrace_filter); #ifdef CONFIG_FUNCTION_GRAPH_TRACER static char ftrace_graph_buf[FTRACE_FILTER_SIZE] __initdata; +static int ftrace_set_func(unsigned long *array, int *idx, char *buffer); + static int __init set_graph_function(char *str) { strlcpy(ftrace_graph_buf, str, FTRACE_FILTER_SIZE); @@ -3351,6 +3354,7 @@ void ftrace_graph_init_task(struct task_struct *t) { /* Make sure we do not use the parent ret_stack */ t->ret_stack = NULL; + t->curr_ret_stack = -1; if (ftrace_graph_active) { struct ftrace_ret_stack *ret_stack; @@ -3360,7 +3364,6 @@ void ftrace_graph_init_task(struct task_struct *t) GFP_KERNEL); if (!ret_stack) return; - t->curr_ret_stack = -1; atomic_set(&t->tracing_graph_pause, 0); atomic_set(&t->trace_overrun, 0); t->ftrace_timestamp = 0; |