* Carlos Llamas <cmllamas@xxxxxxxxxx> [220809 17:02]: > On Tue, Aug 09, 2022 at 07:02:17PM +0000, Liam Howlett wrote: > > > > > > do we need to hold on to the lock while we loop through the pages here? > > > > I think we do? Holding this lock will ensure the pages don't go away, I > > believe (looking at mm/rmap.c comments on locking at the top)? > > > > In any case, this function is called from print_binder_proc_stats() > > which looks to be a debugfs/debugging call so I thought safer would be > > better than faster and with a potential race. > > The pages are protected by alloc->mutex, so you could immediately > release the mmap lock after binder_alloc_get_vma() call. I agree this > is a debugging call so it would be nice to reduce contention. Oh, I see. The reuse of page confused me here. Yes, you are correct. I can re-spin this patch. Thanks, Liam
