On Mon, Oct 02, 2017 at 03:25:10PM +0300, Rakesh Pandit wrote: > On Mon, Oct 02, 2017 at 02:09:35PM +0200, Javier González wrote: > > > On 1 Oct 2017, at 15.25, Rakesh Pandit <[email protected]> wrote: > > > > > > While separating read and erase mempools in 22da65a1b pblk_g_rq_cache > > > was used two times to set aside memory both for erase and read > > > requests. Because same kmem cache is used repeatedly a single call to > > > kmem_cache_destroy wouldn't deallocate everything. Repeatedly doing > > > loading and unloading of pblk modules would eventually result in some > > > leak. > > > > > > The fix is to really use separate kmem cache and track it > > > appropriately. > > > > > > Fixes: 22da65a1b ("lightnvm: pblk: decouple read/erase mempools") > > > Signed-off-by: Rakesh Pandit <[email protected]> > > > > > > > I'm not sure I follow this logic. I assume that you're thinking of the > > refcount on kmem_cache. During cache creation, all is good; if a > > different cache creation fails, destruction is guaranteed, since the > > refcount is 0. On tear down (pblk_core_free), we destroy the mempools > > associated to the caches. In this case, the refcount goes to 0 too, as > > we destroy the 2 mempools. So I don't see where the leak can happen. Am > > I missing something? > > > > In any case, Jens reported some bugs on the mempools, where we did not > > guarantee forward progress. Here you can find the original discussion > > and the mempool audit [1]. Would be good if you reviewed these. > > > > [1] https://www.spinics.net/lists/kernel/msg2602274.html > > > > Thanks, yes makes sense to follow up in patch thread. I will respond > to above questions there later today. >
I wasn't thinking it right in addition to looking at test results from a incorrectly instrumented debugged version. I went through the series you pointed and all seem okay to me now. Please drop this patch. Regards,
