ftrace: Get rid of ftrace_profile_bits

It seems that function profiler's hash size is fixed at 1024.  Add and
use FTRACE_PROFILE_HASH_BITS instead and update hash size macro.

Link: http://lkml.kernel.org/r/1365551750-4504-1-git-send-email-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 3b84fc1..9b44abb 100644 (file)
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -486,7 +486,6 @@ struct ftrace_profile_stat {
 #define PROFILES_PER_PAGE                                      \
        (PROFILE_RECORDS_SIZE / sizeof(struct ftrace_profile))
 
-static int ftrace_profile_bits __read_mostly;
 static int ftrace_profile_enabled __read_mostly;
 
 /* ftrace_profile_lock - synchronize the enable and disable of the profiler */
@@ -494,7 +493,8 @@ static DEFINE_MUTEX(ftrace_profile_lock);
 
 static DEFINE_PER_CPU(struct ftrace_profile_stat, ftrace_profile_stats);
 
-#define FTRACE_PROFILE_HASH_SIZE 1024 /* must be power of 2 */
+#define FTRACE_PROFILE_HASH_BITS 10
+#define FTRACE_PROFILE_HASH_SIZE (1 << FTRACE_PROFILE_HASH_BITS)
 
 static void *
 function_stat_next(void *v, int idx)
@@ -725,13 +725,6 @@ static int ftrace_profile_init_cpu(int cpu)
        if (!stat->hash)
                return -ENOMEM;
 
-       if (!ftrace_profile_bits) {
-               size--;
-
-               for (; size; size >>= 1)
-                       ftrace_profile_bits++;
-       }
-
        /* Preallocate the function profiling pages */
        if (ftrace_profile_pages_init(stat) < 0) {
                kfree(stat->hash);
@@ -765,7 +758,7 @@ ftrace_find_profiled_func(struct ftrace_profile_stat *stat, unsigned long ip)
        struct hlist_node *n;
        unsigned long key;
 
-       key = hash_long(ip, ftrace_profile_bits);
+       key = hash_long(ip, FTRACE_PROFILE_HASH_BITS);
        hhd = &stat->hash[key];
 
        if (hlist_empty(hhd))
@@ -784,7 +777,7 @@ static void ftrace_add_profile(struct ftrace_profile_stat *stat,
 {
        unsigned long key;
 
-       key = hash_long(rec->ip, ftrace_profile_bits);
+       key = hash_long(rec->ip, FTRACE_PROFILE_HASH_BITS);
        hlist_add_head_rcu(&rec->node, &stat->hash[key]);
 }