From: "Uladzislau Rezki (Sony)" <urezki@xxxxxxxxx> Subject: mm/vmalloc.c: get rid of one single unlink_va() when merge It does not make sense to try to "unlink" the node that is definitely not linked with a list nor tree. On the first merge step VA just points to the previously disconnected busy area. On the second step, check if the node has been merged and do "unlink" if so, because now it points to an object that must be linked. Link: http://lkml.kernel.org/r/20190606120411.8298-4-urezki@xxxxxxxxx Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx> Acked-by: Hillf Danton <hdanton@xxxxxxxx> Reviewed-by: Roman Gushchin <guro@xxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Oleksiy Avramchenko <oleksiy.avramchenko@xxxxxxxxxxxxxx> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmalloc.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) --- a/mm/vmalloc.c~mm-vmallocc-get-rid-of-one-single-unlink_va-when-merge +++ a/mm/vmalloc.c @@ -719,9 +719,6 @@ merge_or_add_vmap_area(struct vmap_area /* Check and update the tree if needed. */ augment_tree_propagate_from(sibling); - /* Remove this VA, it has been merged. */ - unlink_va(va, root); - /* Free vmap_area object. */ kmem_cache_free(vmap_area_cachep, va); @@ -746,12 +743,11 @@ merge_or_add_vmap_area(struct vmap_area /* Check and update the tree if needed. */ augment_tree_propagate_from(sibling); - /* Remove this VA, it has been merged. */ - unlink_va(va, root); + if (merged) + unlink_va(va, root); /* Free vmap_area object. */ kmem_cache_free(vmap_area_cachep, va); - return; } } _
