On 03/06/2011 07:03 PM, Benjamin Herrenschmidt wrote: > Currently memblock_reserve() or memblock_free() don't handle overlaps > of any kind. There is some special casing for coalescing exactly > adjacent regions but that's about it. > > This is annoying because typically memblock_reserve() is used to > mark regions passed by the firmware as reserved and we all know > how much we can trust our firmwares... > > Also, with the current code, if we do something it doesn't handle > right such as trying to memblock_reserve() a large range spanning > multiple existing smaller reserved regions for example, or doing > overlapping reservations, it can silently corrupt the internal > region array, causing odd errors much later on, such as allocations > returning reserved regions etc... > > This patch rewrites the underlying functions that add or remove a > region to the arrays. The new code is a lot more robust as it fully > handles overlapping regions. It's also, imho, simpler than the previous > implementation. > > In addition, while doing so, I found a bug where if we fail to double > the array while adding a region, we would remove the last region of > the array rather than the region we just allocated. This fixes it too. > > Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > --- > > Hopefully not damaged with a spurious bit of email header this > time around... sorry about that. works on my setups... [ 0.000000] Subtract (26 early reservations) [ 0.000000] [000009a000-000009efff] [ 0.000000] [000009f400-00000fffff] [ 0.000000] [0001000000-0003495048] ... before: [ 0.000000] Subtract (27 early reservations) [ 0.000000] [000009a000-000009efff] [ 0.000000] [000009f400-00000fffff] [ 0.000000] [00000f85b0-00000f86b3] [ 0.000000] [0001000000-0003495048] Acked-by: Yinghai Lu <yinghai@xxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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>