On 06/22/2011 11:00 AM, Andrew Morton wrote: > : > : Second, the BadRAM patch expands the address patterns from the command > : line into individual entries in the kernel's e820 table. The e820 > : table is a fixed buffer that supports a very small, hard coded number > : of entries (128). We require a much larger number of entries (on > : the order of a few thousand), so much of the google kernel patch deals > : with expanding the e820 table. This has not been true for a long time. > I have a couple of thoughts here: > > - If this patchset is merged and a major user such as google is > unable to use it and has to continue to carry a separate patch then > that's a regrettable situation for the upstream kernel. > > - Google's is, afaik, the largest use case we know of: zillions of > machines for a number of years. And this real-world experience tells > us that the badram patchset has shortcomings. Shortcomings which we > can expect other users to experience. > > So. What are your thoughts on these issues? I think a binary structure fed as a linked list data object makes a lot more sense. We already support feeding e820 entries in this way, bypassing the 128-entry limitation of the fixed table in the zeropage. The main issue then is priority; in particular memory marked UNUSABLE (type 5) in the fed-in e820 map will of course overlap entries with normal RAM (type 1) information in the native map; we need to make sure that the type 5 information takes priority. -hpa -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>