Peter Zijlstra <pet...@infradead.org> writes: > On Mon, Nov 09, 2015 at 02:53:56PM +1030, Rusty Russell wrote: >> diff --git a/kernel/module.c b/kernel/module.c >> index 14b224967e7b..a0a3d6d9d5e8 100644 >> --- a/kernel/module.c >> +++ b/kernel/module.c >> @@ -108,13 +108,6 @@ static LIST_HEAD(modules); >> * Use a latched RB-tree for __module_address(); this allows us to use >> * RCU-sched lookups of the address from any context. >> * >> - * Because modules have two address ranges: init and core, we need two >> - * latch_tree_nodes entries. Therefore we need the back-pointer from >> - * mod_tree_node. > > We still have the back-pointers, so removing all of that seems a little > excessive.
Well, I thought about filling the hole with a "am_init" flag, and putting the layouts in a [2] array, but seemed too cutesy. >> - * >> - * Because init ranges are short lived we mark them unlikely and have placed >> - * them outside the critical cacheline in struct module. > > This information also isn't preserved. Ah yeah, Intel still use 64-byte cachelines. Still, this comment covers what we actually care about: +#ifdef CONFIG_MODULES_TREE_LOOKUP +/* Only touch one cacheline for common rbtree-for-core-layout case. */ +#define __module_layout_align ____cacheline_aligned +#else +#define __module_layout_align +#endif > Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org> Thanks! Rusty. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
