On Tue, May 29, 2012 at 02:24:58PM +0900, Tejun Heo wrote: > > So in practice there's no extra stack usage. Whether this is an > > optimization we want to depend I'm not going to say; I suspect it's > > pretty safe w.r.t. the optimizer but it's definitely sketchy and if at > > some point someone came along and switched it to the uninline version > > we'd have problems. > > I don't think we can depend on that. Note that compiler may as well > decide not to inline an inline function (e.g. if it sees many calling > instances). Depending on such behavior is way too fragile. Bah, I forgot about the compiler uninlining stuff. There's __always_inline, but... yeah, I agree, too dangerous. > > So we might want to leave this one open coded. Which would make me sad, > > but I can't think of a sane way of implementing generic rb_search() that > > doesn't require passing it a type t to compare against. > > I don't know either. Open coding isn't the end of the world but I > suspect a lot of data structures which go on rbtree wouldn't be stack > friendly, so having common helper which can't handle that might not be > too helpful. There's > 100 users in the kernel, I have no clue what the average size of the containing struct is. I think I'm gonna split rb_search() out into its own patch, as rb_insert() fortunately doesn't have this problem. I'm starting to think the sanest solution is a macro (not quite my original RB_SEARCH() macro, though). -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
