On Thu, Jan 28, 2016 at 02:27:44PM +0100, Alexander Potapenko wrote: > On Thu, Jan 28, 2016 at 1:51 PM, Alexander Potapenko <glider@xxxxxxxxxx> wrote: > > > > 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. Okay. > > 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@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>