On Thu, Jan 28, 2016 at 02:27:44PM +0100, Alexander Potapenko wrote:

On Thu, Jan 28, 2016 at 1:51 PM, Alexander Potapenko [off-list ref] wrote:

quoted

On Jan 28, 2016 8:40 AM, "Joonsoo Kim" [off-list ref] wrote:

quoted

Hello,

On Wed, Jan 27, 2016 at 07:25:10PM +0100, Alexander Potapenko wrote:

quoted

Stack depot will allow KASAN store allocation/deallocation stack traces
for memory chunks. The stack traces are stored in a hash table and
referenced by handles which reside in the kasan_alloc_meta and
kasan_free_meta structures in the allocated memory chunks.

Looks really nice!

Could it be more generalized to be used by other feature that need to
store stack trace such as tracepoint or page owner?

Certainly yes, but see below.

quoted

If it could be, there is one more requirement.
I understand the fact that entry is never removed from depot makes things
very simpler, but, for general usecases, it's better to use reference
count
and allow to remove. Is it possible?

For our use case reference counting is not really necessary, and it would
introduce unwanted contention.

Okay.

quoted

There are two possible options, each having its advantages and drawbacks: we
can let the clients store the refcounters directly in their stacks (more
universal, but harder to use for the clients), or keep the counters in the
depot but add an API that does not change them (easier for the clients, but
potentially error-prone).
I'd say it's better to actually find at least one more user for the stack
depot in order to understand the requirements, and refactor the code after
that.

I re-think the page owner case and it also may not need refcount.
For now, just moving this stuff to /lib would be helpful for other future user.

BTW, is there any performance number? I guess that it could affect
the performance.

Thanks.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>