Commit-ID: 9644302e3315e7e36495d230d5ac7125a316d33e
Gitweb: http://git.kernel.org/tip/9644302e3315e7e36495d230d5ac7125a316d33e
Author: Steven Rostedt <srostedt@xxxxxxxxxx>
AuthorDate: Wed, 25 Apr 2012 10:14:43 -0400
Committer: Steven Rostedt <rostedt@xxxxxxxxxxx>
CommitDate: Wed, 16 May 2012 19:58:46 -0400
ftrace: Speed up search by skipping pages by address
As all records in a page of the ftrace table are sorted, we can
speed up the search algorithm by checking if the address to look for
falls in between the first and last record ip on the page.
This speeds up both the ftrace_location() and ftrace_text_reserved()
algorithms, as it can skip full pages when the search address is
not in them.
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
---
kernel/trace/ftrace.c | 22 ++++++++++++++++------
1 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index e10f9e5..fc93562 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1411,6 +1411,8 @@ int ftrace_location(unsigned long ip)
key.ip = ip;
for (pg = ftrace_pages_start; pg; pg = pg->next) {
+ if (ip < pg->records[0].ip || ip > pg->records[pg->index - 1].ip)
+ continue;
rec = bsearch(&key, pg->records, pg->index,
sizeof(struct dyn_ftrace),
ftrace_cmp_recs);
@@ -1571,16 +1573,24 @@ void ftrace_bug(int failed, unsigned long ip)
/* Return 1 if the address range is reserved for ftrace */
-int ftrace_text_reserved(void *start, void *end)
+int ftrace_text_reserved(void *s, void *e)
{
struct dyn_ftrace *rec;
struct ftrace_page *pg;
+ unsigned long start = (unsigned long)s;
+ unsigned long end = (unsigned long)e;
+ int i;
- do_for_each_ftrace_rec(pg, rec) {
- if (rec->ip <= (unsigned long)end &&
- rec->ip + MCOUNT_INSN_SIZE > (unsigned long)start)
- return 1;
- } while_for_each_ftrace_rec();
+ for (pg = ftrace_pages_start; pg; pg = pg->next) {
+ if (end < pg->records[0].ip ||
+ start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE))
+ continue;
+ for (i = 0; i < pg->index; i++) {
+ rec = &pg->records[i];
+ if (rec->ip <= end && rec->ip + MCOUNT_INSN_SIZE > start)
+ return 1;
+ }
+ }
return 0;
}
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|