On Tue, Dec 22, 2020 at 2:00 AM Oscar Salvador <osalvador@xxxxxxx> wrote: > > On Mon, Dec 21, 2020 at 11:52:30PM +0800, Muchun Song wrote: > > On Mon, Dec 21, 2020 at 9:44 PM Oscar Salvador <osalvador@xxxxxxx> wrote: > > > > > > On Mon, Dec 21, 2020 at 07:25:15PM +0800, Muchun Song wrote: > > > > > > > Should we add a BUG_ON in vmemmap_remap_free() for now? > > > > > > > > BUG_ON(reuse != start + PAGE_SIZE); > > > > > > I do not think we have to, plus we would be BUG_ing for some specific use > > > case in "generic" function. > > > > The vmemmap_remap_range() walks page table range [start, end), > > if reuse is equal to (start + PAGE_SIZE), the range can adjust to > > [start - PAGE_SIZE, end). But if not, we need some work to > > implement the "generic" function. > > > > - adjust range to [min(start, reuse), end) and call > > vmemmap_remap_rangeand which skip the hole > > which is [reuse + PAGE_SIZE, start) or [end, reuse). > > - call vmemmap_remap_range(reuse, reuse + PAGE_SIZE) > > to get the reuse page.Then, call vmemmap_remap_range(start, end) > > again to remap. > > > > Which one do you prefer? > > I would not overcomplicate things at this stage. > Just follow my sugestion and add a BUG_ON as you said, that might be the > easier way now. > We can overthink this in the future when some other usecases come > around, right? You are right. Will do this. Thanks for your suggestions. > > Thanks > > > -- > Oscar Salvador > SUSE L3 -- Yours, Muchun
