On Sun, 2005-08-28 at 17:52 -0700, Andrew Morton wrote: > > +#if BITS_PER_LONG == 32 > > +#define RADIX_TREE_MAP_SHIFT 5 > > +#elif BITS_PER_LONG == 64 > > ... > > struct radix_tree_node { > > - unsigned int count; > > void *slots[RADIX_TREE_MAP_SIZE]; > > - unsigned long tags[RADIX_TREE_TAGS][RADIX_TREE_TAG_LONGS]; > > + unsigned long tags[RADIX_TREE_TAGS]; > > }; > > I don't see why the above change was necessary? Why not stick with the > current more flexible sizing option? > > Note that the RADIX_TREE_MAP_FULL trick can still be used. It just has to > be put inside a `for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++)' loop, > which will vanish if RADIX_TREE_TAG_LONGS==1.
Well ... It's my opinion (and purely unsubstantiated, I suppose) that it's more efficient on 32 bit platforms to do bit operations on 32 bit quantities, which is why I changed the radix tree map shift to 5 for that case. It also makes much cleaner code than having to open code checks on variable sized bitmaps. James - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/