Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Sun, 11 Feb 2018 13:16:46 -0800
From: Matthew Wilcox <>
To: Igor Stoppa <>
Subject: Re: [PATCH 3/6] struct page: add field for vm_struct

On Sun, Feb 11, 2018 at 05:19:17AM +0200, Igor Stoppa wrote:
> The struct page has a "mapping" field, which can be re-used, to store a
> pointer to the parent area. This will avoid more expensive searches.
> As example, the function find_vm_area is reimplemented, to take advantage
> of the newly introduced field.

Umm.  Is it more efficient?  You're replacing an rb-tree search with a
page-table walk.  You eliminate a spinlock, which is great, but is the
page-table walk more efficient?  I suppose it'll depend on the depth of
the rb-tree, and (at least on x86), the page tables should already be
in cache.

Unrelated to this patch, I'm working on a patch to give us page_type,
and I think I'll allocate a bit to mark pages which are vmalloced.

Powered by blists - more mailing lists

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.