summaryrefslogtreecommitdiffstats
path: root/kernel/trace
diff options
context:
space:
mode:
authorSteven Rostedt <srostedt@redhat.com>2011-12-16 19:27:42 -0500
committerSteven Rostedt <rostedt@goodmis.org>2011-12-21 07:20:50 -0500
commit5855fead9cc358adebd6bdeec202d040c623ae38 (patch)
treec95d272ff41b7873cc33feef3686ede3f020d4cd /kernel/trace
parent68950619f8c82e468d8976130462617abea605a8 (diff)
downloadop-kernel-dev-5855fead9cc358adebd6bdeec202d040c623ae38.zip
op-kernel-dev-5855fead9cc358adebd6bdeec202d040c623ae38.tar.gz
ftrace: Use bsearch to find record ip
Now that each set of pages in the function list are sorted by ip, we can use bsearch to find a record within each set of pages. This speeds up the ftrace_location() function by magnitudes. For archs (like x86) that need to add a breakpoint at every function that will be converted from a nop to a callback and vice versa, the breakpoint callback needs to know if the breakpoint was for ftrace or not. It requires finding the breakpoint ip within the records. Doing a linear search is extremely inefficient. It is a must to be able to do a fast binary search to find these locations. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ftrace.c38
1 files changed, 23 insertions, 15 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 2d6f8bc..dcd3a81 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -22,6 +22,7 @@
#include <linux/hardirq.h>
#include <linux/kthread.h>
#include <linux/uaccess.h>
+#include <linux/bsearch.h>
#include <linux/module.h>
#include <linux/ftrace.h>
#include <linux/sysctl.h>
@@ -1300,6 +1301,19 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip)
} \
}
+
+static int ftrace_cmp_recs(const void *a, const void *b)
+{
+ const struct dyn_ftrace *reca = a;
+ const struct dyn_ftrace *recb = b;
+
+ if (reca->ip > recb->ip)
+ return 1;
+ if (reca->ip < recb->ip)
+ return -1;
+ return 0;
+}
+
/**
* ftrace_location - return true if the ip giving is a traced location
* @ip: the instruction pointer to check
@@ -1313,11 +1327,17 @@ int ftrace_location(unsigned long ip)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
+ struct dyn_ftrace key;
- do_for_each_ftrace_rec(pg, rec) {
- if (rec->ip == ip)
+ key.ip = ip;
+
+ for (pg = ftrace_pages_start; pg; pg = pg->next) {
+ rec = bsearch(&key, pg->records, pg->index,
+ sizeof(struct dyn_ftrace),
+ ftrace_cmp_recs);
+ if (rec)
return 1;
- } while_for_each_ftrace_rec();
+ }
return 0;
}
@@ -3587,18 +3607,6 @@ static void ftrace_swap_recs(void *a, void *b, int size)
*recb = t;
}
-static int ftrace_cmp_recs(const void *a, const void *b)
-{
- const struct dyn_ftrace *reca = a;
- const struct dyn_ftrace *recb = b;
-
- if (reca->ip > recb->ip)
- return 1;
- if (reca->ip < recb->ip)
- return -1;
- return 0;
-}
-
static int ftrace_process_locs(struct module *mod,
unsigned long *start,
unsigned long *end)
OpenPOWER on IntegriCloud