On Wed 17-08-22 08:00:45, Christoph Hellwig wrote: > On Mon, Aug 15, 2022 at 10:42:01AM +0200, Michal Hocko wrote: > > Anyway, you seem to be not thrilled about the __GFP_NOWARN approach and > > I won't push it. But is the existing inconsistency really desirable? I > > mean we can get pretty vocal warning if the allocation fails but no > > information when the zone doesn't have any managed memory. Why should we > > treat them differently? > > How could we end up having ZONE_DMA without any managed memory to start > with except for the case where the total memory is smaller than what > fits into ZONE_DMA? If we have such a case we really should warn about > it as well. This can be an early memory reservation from this physical address range. My original report http://lkml.kernel.org/r/Yj28gjonUa9+0yae@xxxxxxxxxxxxxx was referring to such a system (a different one than what I am dealing with now): present:636kB managed:0kB There is only 636kB present in that ZONE_DMA physical range but nothing has made it to the page allocator in the end. -- Michal Hocko SUSE Labs
