linux-kernel - Re: [RFC 1/4] mm: refactor __vunmap() to avoid duplicated call to find_vm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 14 Dec 2018 10:24:52 -0800
From:   Matthew Wilcox <willy@...radead.org>
To:     Roman Gushchin <guroan@...il.com>
Cc:     linux-mm@...ck.org, Alexey Dobriyan <adobriyan@...il.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Michal Hocko <mhocko@...e.com>,
        Vlastimil Babka <vbabka@...e.cz>, linux-kernel@...r.kernel.org,
        kernel-team@...com, Roman Gushchin <guro@...com>
Subject: Re: [RFC 1/4] mm: refactor __vunmap() to avoid duplicated call to
 find_vm_area()

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@...com>
> Acked-by: Johannes Weiner <hannes@...xchg.org>

Reviewed-by: Matthew Wilcox <willy@...radead.org>