From 9644302e3315e7e36495d230d5ac7125a316d33e Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 25 Apr 2012 10:14:43 -0400 Subject: [PATCH] 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 Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 22 ++++++++++++++++------ 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index e10f9e522c4..fc93562a665 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; } -- 2.20.1