On Jan 28, 2016 8:40 AM, "Joonsoo Kim" <iamjoonsoo.kim@xxxxxxx> wrote:
>
> Hello,
>
> On Wed, Jan 27, 2016 at 07:25:10PM +0100, Alexander Potapenko wrote:
> > 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.
> 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.
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.
> Thanks.
>