[PATCH v2] ftrace: Do not copy old hash when resetting.

From: Wang Nan
Date: Mon Jul 14 2014 - 20:50:12 EST


If we are going to reset hash, we don't need to duplicate old hash
and remove every entries right after allocation.

Change from v1:
- if statement is swapped to make condition positive.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>

---
kernel/trace/ftrace.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 5b372e3..aa61d01 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -3471,14 +3471,16 @@ ftrace_set_hash(struct ftrace_ops *ops, unsigned char *buf, int len,
else
orig_hash = &ops->notrace_hash;

- hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+ if (reset)
+ hash = alloc_ftrace_hash(FTRACE_HASH_DEFAULT_BITS);
+ else
+ hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, *orig_hash);
+
if (!hash) {
ret = -ENOMEM;
goto out_regex_unlock;
}

- if (reset)
- ftrace_filter_reset(hash);
if (buf && !ftrace_match_records(hash, buf, len)) {
ret = -EINVAL;
goto out_regex_unlock;
--
1.8.4

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