On Mon, Jul 22, 2019 at 7:25 AM Robin Murphy <robin.murphy@xxxxxxx> wrote: > > On 22/07/2019 13:19, Steven Price wrote: > [...] > > Indeed, that case was just occurring to me too! How about: > > > > u64 next_seg = ALIGN(*start, PFN_4G); > > > > if (next_seg - *start <= PFN_16M) > > *start = next_seg + 1; This could make start > end... It also doesn't handle not starting on a 4G boundary (or was that condition check supposed to be included still). > > > > *end = min(*end, ALIGN(*start, PFN_4G) - 1); > > > > So always allocate at the beginning, but skip past the next 4GB boundary > > if there's less than 16MB left (or equal to avoid the 4GB boundary). > > Ah, there it is! I think it generalises even further by just changing > the condition to "if (next_seg - *start < *end - next_seg)", although > we'd need to ensure a signed comparison to cover the case where start > and end are already in the same segment. IMO, relying on signed comparsion doesn't really improve the readability... Rob _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
