Re: [RFC 1/4] mm: refactor __vunmap() to avoid duplicated call to find_vm_area()

From: Matthew Wilcox
Date: Fri Dec 14 2018 - 13:24:59 EST

On Fri, Dec 14, 2018 at 10:07:17AM -0800, Roman Gushchin wrote:
> __vunmap() calls find_vm_area() twice without an obvious reason:
> first directly to get the area pointer, second indirectly by calling
> remove_vm_area(), which is again searching for the area.
> To remove this redundancy, let's split remove_vm_area() into
> __remove_vm_area(struct vmap_area *), which performs the actual area
> removal, and remove_vm_area(const void *addr) wrapper, which can
> be used everywhere, where it has been used before.
> On my test setup, I've got up to 12% speed up on vfree()'ing 1000000
> of 4-pages vmalloc blocks.
> Signed-off-by: Roman Gushchin <guro@xxxxxx>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>