On Thu, Jul 19, 2018 at 05:16:42PM +0200, Duy Nguyen wrote: > On Thu, Jul 19, 2018 at 07:57:37AM +0200, Duy Nguyen wrote: > > I thought 2M was generous but I was obviously wrong. I'd like to see > > the biggest delta size in this pack and whether it's still reasonable > > to increase OE_DELTA_SIZE_BITS. But if it's very close to 4GB limit > > then we could just store 64-bit delta size in a separate array. > > I realize now that these two options don't have to be mutually > exclusive and I should provide a good fallback in terms of performance > anyway. Yeah, this is what I had assumed was happening in the original code. :) > +void oe_prepare_delta_size_array(struct packing_data *pack) > +{ > + int i; > + > + /* > + * nr_alloc, not nr_objects to align with realloc() strategy in > + * packlist_alloc() > + */ > + ALLOC_ARRAY(pack->delta_size, pack->nr_alloc); > + > + for (i = 0; i < pack->nr_objects; i++) > + pack->delta_size[i] = pack->objects[i].delta_size_; > +} This iterator should probably be a uint32_t, to match nr_objects. The rest of the patch looks OK to me. From Elijah's failure report there clearly is _some_ problem where we end up with a truncated write of a delta. But I don't see it from code inspection, nor could I reproduce it. -Peff