debugobjects: Export max loops counter

__debug_check_no_obj_freed() can be an expensive operation depending on the
size of memory freed. It already exports the maximum chain walk length via
debugfs, but this only records the maximum of a single memory chunk.

Though there is no information about the total number of objects inspected
for a __debug_check_no_obj_freed() operation, which might be significantly
larger when a huge memory region is freed.

Aggregate the number of objects inspected for a single invocation of
__debug_check_no_obj_freed() and export it via sysfs.

The resulting output of /sys/kernel/debug/debug_objects/stats looks like:

max_chain     :121
max_checked   :543267
warnings      :0
fixups        :0
pool_free     :1764
pool_min_free :341
pool_used     :86438
pool_max_used :268887
objs_allocated:6068254
objs_freed    :5981076

[ tglx: Renamed the variable to max_checked and adjusted changelog ]

Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: longman@redhat.com
Link: https://lkml.kernel.org/r/1517872708-24207-2-git-send-email-yang.shi@linux.alibaba.com
This commit is contained in:
Yang Shi 2018-02-06 07:18:25 +08:00 committed by Thomas Gleixner
parent 7928b2cbe5
commit bd9dcd0465

View File

@ -50,6 +50,7 @@ static int obj_pool_max_used;
static struct kmem_cache *obj_cache;
static int debug_objects_maxchain __read_mostly;
static int debug_objects_maxchecked __read_mostly;
static int debug_objects_fixups __read_mostly;
static int debug_objects_warnings __read_mostly;
static int debug_objects_enabled __read_mostly
@ -720,7 +721,7 @@ static void __debug_check_no_obj_freed(const void *address, unsigned long size)
enum debug_obj_state state;
struct debug_bucket *db;
struct debug_obj *obj;
int cnt;
int cnt, objs_checked = 0;
saddr = (unsigned long) address;
eaddr = saddr + size;
@ -765,7 +766,12 @@ repeat:
if (cnt > debug_objects_maxchain)
debug_objects_maxchain = cnt;
objs_checked += cnt;
}
if (objs_checked > debug_objects_maxchecked)
debug_objects_maxchecked = objs_checked;
}
void debug_check_no_obj_freed(const void *address, unsigned long size)
@ -780,6 +786,7 @@ void debug_check_no_obj_freed(const void *address, unsigned long size)
static int debug_stats_show(struct seq_file *m, void *v)
{
seq_printf(m, "max_chain :%d\n", debug_objects_maxchain);
seq_printf(m, "max_checked :%d\n", debug_objects_maxchecked);
seq_printf(m, "warnings :%d\n", debug_objects_warnings);
seq_printf(m, "fixups :%d\n", debug_objects_fixups);
seq_printf(m, "pool_free :%d\n", obj_pool_free);