On Mon, Aug 06, 2007 at 11:40:55AM -0700, Andrew Morton wrote: > On Thu, 2 Aug 2007 07:24:46 +0200 Nick Piggin <[EMAIL PROTECTED]> wrote: > > > Rather than sign direct radix-tree pointers with a special bit, sign > > the indirect one that hangs off the root. This means that, given a > > lookup_slot operation, the invalid result will be differentiated from > > the valid (previously, valid results could have the bit either set or > > clear). > > > > This does not affect slot lookups which occur under lock -- they > > can never return an invalid result. Is needed in future for lockless > > pagecache. > > so.. we added 30 bytes of text to radix-tree.o for no purpose?
I guess no functional purpose at this stage. But I do like this scheme better anyway, because it means that locked API users are never exposed to the direct/indirect bit. It's a bit variable... on powerpc, it _removed_ 22 bytes, and if I delete the extra BUG_ON that I introduced, then it removes 128 bytes. - 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/
