On Fri, Jul 21, 2017 at 06:01:41PM +0800, Zhaoyang Huang wrote: > we just record the cached_hole_size now, which will be used when > the criteria meet both of 'free_vmap_cache == NULL' and 'size < > cached_hole_size'. However, under above scenario, the search will > start from the rb_root and then find the node which just in front > of the cached hole. > > free_vmap_cache miss: > vmap_area_root > / \ > _next U > / (T1) > cached_hole_node > / > ... (T2) > / > first > > vmap_area_list->first->......->cached_hole_node->cached_hole_node.list.next > |-------(T3)-------| | <<< cached_hole_size >>> | > > vmap_area_list->......->cached_hole_node->cached_hole_node.list.next > | <<< cached_hole_size >>> | > > The time cost to search the node now is T = T1 + T2 + T3. > The commit add a cached_hole_node here to record the one just in front of > the cached_hole_size, which can help to avoid walking the rb tree and > the list and make the T = 0; Yes, but does this matter in practice? Are there any workloads where this makes a difference? If so, how much? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
