From: Keir Fraser <keir@xensource.com>
To: Jan Beulich <jbeulich@novell.com>, Keir Fraser <keir@xensource.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: Fwd: Re: struct page field arrangement
Date: Thu, 01 Mar 2007 12:12:13 +0000 [thread overview]
Message-ID: <C20C739D.A694%keir@xensource.com> (raw)
In-Reply-To: <45E6CB06.76E4.0078.0@novell.com>
On 1/3/07 11:45, "Jan Beulich" <jbeulich@novell.com> wrote:
>> Can we confident that the mm_pin/mm_unpin code (which walks pagetables and
>> has to find every page to make every one read-only or writable) is safe?
>> Presumably for this to be true we need to be sure that noone can meanwhile
>> concurrently be populating the pagetable we are walking with extra
>> pgds/puds/pmds/ptes...
>
> Since the pin/unpin walking only cares about pgd/pud/pmd entries,
> synchronization
> is guaranteed through mm->page_table_lock. The pte lock is used only for leaf
> entries, which are of no concern to (un)pinning.
Oh yes, of course.
By the way, I think your proposed patch looks okay. However we already use
page->index for foreign pages, in netback. Perhaps page->lru is also fair
game? :-)
K.
next prev parent reply other threads:[~2007-03-01 12:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-28 14:31 struct page field arrangement Jan Beulich
2007-02-28 21:08 ` Hugh Dickins
2007-03-01 8:42 ` Fwd: " Jan Beulich
2007-03-01 10:22 ` Keir Fraser
2007-03-01 11:45 ` Jan Beulich
2007-03-01 12:12 ` Keir Fraser [this message]
2007-03-01 12:50 ` Jan Beulich
2007-03-01 13:42 ` Keir Fraser
-- strict thread matches above, loose matches on Subject: below --
2007-03-16 11:58 Jan Beulich
2007-03-16 12:11 ` Keir Fraser
2007-03-16 12:25 ` Keir Fraser
2007-03-16 12:54 ` Jan Beulich
2007-03-16 12:37 ` Keir Fraser
2007-03-16 12:46 ` Jan Beulich
2007-03-16 13:47 Jan Beulich
2007-03-16 14:13 ` Keir Fraser
2007-03-16 14:30 ` Keir Fraser
2007-03-16 15:15 ` Jan Beulich
2007-03-16 15:30 ` Keir Fraser
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