Re: [RFC PATCH 1/2] lib: debugobjects: export max loops counter

From: Yang Shi
Date: Mon Nov 27 2017 - 13:53:55 EST




On 11/27/17 10:08 AM, Waiman Long wrote:
On 11/27/2017 12:53 PM, Yang Shi wrote:
Hi Waiman & tglx,

I'm not sure who is the maintainer for lib/debugobjects.c now, I'm
supposed tglx still is, however, get_maintainer.pl told me Waiman is
the most active developer of this, so added Waiman in this loop in
case he didn't see the patches on LKML.

Thanks,
Yang

On 11/17/17 11:43 AM, Yang Shi wrote:
Currently max chain counter is exported to sysfs, it just record the

It is the debugfs, which is different from sysfs.

Will correct it.


counter of inner loop, however, there might be significant iterations of
external loop then it may take significant amount of time to finish all
of the checks. This may cuase lockup on !CONFIG_PREEMPT kernel build
occasionally.

Record the counter of the max loops then export to sysfs so that the
user can be aware of the real overhead.

Then the output of /sys/kernel/debug/debug_objects/stats looks like:

max_chain :121
max_loops :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

Signed-off-by: Yang Shi <yang.s@xxxxxxxxxxxxxxx>

I have no objection to adding one more tracking count.

Thanks.

Yang


Cheers,
Longman