From: Ethan Solomita <solo@google.com>
To: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, linux-mm@kvack.org
Subject: Re: page_referenced() and VM_LOCKED
Date: Tue, 04 Dec 2007 16:26:41 -0800 [thread overview]
Message-ID: <4755F041.4000605@google.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0711161749020.12201@blonde.wat.veritas.com>
Hugh Dickins wrote:
> On Fri, 16 Nov 2007, KAMEZAWA Hiroyuki wrote:
>> On Thu, 15 Nov 2007 20:25:45 -0800
>> Ethan Solomita <solo@google.com> wrote:
>>
>>> page_referenced_file() checks for the vma to be VM_LOCKED|VM_MAYSHARE
>>> and adds returns 1.
>
> That's a case where it can deduce that the page is present and should
> be treated as referenced, without even examining the page tables.
>
>>> We don't do the same in page_referenced_anon().
>
> It cannot make that same deduction in the page_referenced_anon() case
> (different vmas may well contain different COWs of some original page).
Sorry to come back in with this so late -- if the vma is VM_MAYSHARE,
would there be COWs of the original page?
-- Ethan
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2007-12-05 0:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-11-16 4:25 Ethan Solomita
2007-11-16 5:46 ` KAMEZAWA Hiroyuki
2007-11-16 18:00 ` Hugh Dickins
2007-12-05 0:26 ` Ethan Solomita [this message]
2007-12-05 15:54 ` Hugh Dickins
2007-11-17 0:32 ` kamezawa.hiroyu
2007-11-19 9:39 ` KAMEZAWA Hiroyuki
2007-11-19 19:09 ` Hugh Dickins
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4755F041.4000605@google.com \
--to=solo@google.com \
--cc=hugh@veritas.com \
--cc=kamezawa.hiroyu@jp.fujitsu.com \
--cc=linux-mm@kvack.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox