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ftrace: Consolidate ftrace_location() and ftrace_text_reserved() 

Both ftrace_location() and ftrace_text_reserved() do basically the same thing.
They search to see if an address is in the ftace table (contains an address
that may change from nop to call ftrace_caller). The difference is
that ftrace_location() searches a single address, but ftrace_text_reserved()
searches a range.

This also makes the ftrace_text_reserved() faster as it now uses a bsearch()
instead of linearly searching all the addresses within a page.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2012-04-25 13:48:13 -04:00 committed by Steven Rostedt
parent 9644302e33
commit a650e02a52
1 changed files with 44 additions and 44 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

88
kernel/trace/ftrace.c
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@ -1383,13 +1383,36 @@ 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;
const struct dyn_ftrace *key = a;
const struct dyn_ftrace *rec = b;
if (reca->ip > recb->ip)
return 1;
if (reca->ip < recb->ip)
if (key->flags < rec->ip)
return -1;
if (key->ip >= rec->ip + MCOUNT_INSN_SIZE)
return 1;
return 0;
}
static int ftrace_location_range(unsigned long start, unsigned long end)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
struct dyn_ftrace key;
key.ip = start;
key.flags = end; /* overload flags, as it is unsigned long */
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;
rec = bsearch(&key, pg->records, pg->index,
sizeof(struct dyn_ftrace),
ftrace_cmp_recs);
if (rec)
return 1;
}
return 0;
}
@ -1404,23 +1427,23 @@ static int ftrace_cmp_recs(const void *a, const void *b)
*/
int ftrace_location(unsigned long ip)
{
struct ftrace_page *pg;
struct dyn_ftrace *rec;
struct dyn_ftrace key;
return ftrace_location_range(ip, 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);
if (rec)
return 1;
}
return 0;
/**
* ftrace_text_reserved - return true if range contains an ftrace location
* @start: start of range to search
* @end: end of range to search (inclusive). @end points to the last byte to check.
*
* Returns 1 if @start and @end contains a ftrace location.
* That is, the instruction that is either a NOP or call to
* the function tracer. It checks the ftrace internal tables to
* determine if the address belongs or not.
*/
int ftrace_text_reserved(void *start, void *end)
{
return ftrace_location_range((unsigned long)start,
(unsigned long)end);
}
static void __ftrace_hash_rec_update(struct ftrace_ops *ops,
@ -1571,29 +1594,6 @@ void ftrace_bug(int failed, unsigned long ip)
}
}
/* Return 1 if the address range is reserved for ftrace */
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;
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;
}
static int ftrace_check_record(struct dyn_ftrace *rec, int enable, int update)
{
unsigned long flag = 0UL;