From: Jonathan Corbet <corbet@lwn.net>
To: Chris Wright <chrisw@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
Izik Eidus <ieidus@redhat.com>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, kvm@vger.kernel.org, aarcange@redhat.com,
avi@redhat.com, dlaor@redhat.com, kamezawa.hiroyu@jp.fujitsu.com,
cl@linux-foundation.org
Subject: Re: [PATCH 3/4] add ksm kernel shared memory driver.
Date: Tue, 2 Dec 2008 14:37:15 -0700 [thread overview]
Message-ID: <20081202143715.1fa03879@bike.lwn.net> (raw)
In-Reply-To: <20081202212411.GG17607@acer.localdomain>
On Tue, 2 Dec 2008 13:24:11 -0800
Chris Wright <chrisw@redhat.com> wrote:
> > Using current known techniques. A random collision is just as bad
> > news.
>
> And, just to clarify, your concern would extend to any digest based
> comparison? Or are you specifically concerned about sha1?
Wouldn't this issue just go away if the code simply compared the full
pages, rather than skipping the hashed 128 bytes at the beginning?
Given the cost of this whole operation (which, it seems, can involve
copying one of the pages before testing for equality), skipping the
comparison of 128 bytes seems like a bit of a premature optimization.
jon
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next prev parent reply other threads:[~2008-12-02 21:37 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-17 2:20 [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 Izik Eidus
2008-11-17 2:20 ` [PATCH 1/4] Rmap: Add page_wrprotect() function Izik Eidus
2008-11-17 2:20 ` [PATCH 2/4] Add replace_page(): change the page pte is pointing to Izik Eidus
2008-11-17 2:20 ` [PATCH 3/4] add ksm kernel shared memory driver Izik Eidus
2008-11-17 2:20 ` [PATCH 4/4] MMU_NOTIFIRES: add set_pte_at_notify() Izik Eidus
2008-11-28 16:58 ` [PATCH 3/4] add ksm kernel shared memory driver Alan Cox
2008-12-02 18:07 ` Chris Wright
2008-12-02 18:13 ` Alan Cox
2008-12-02 21:24 ` Chris Wright
2008-12-02 21:37 ` Jonathan Corbet [this message]
2008-12-02 22:10 ` Alan Cox
2008-12-03 14:33 ` Pavel Machek
2008-12-04 9:48 ` Alan Cox
2008-11-20 7:44 ` [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 Ryota OZAKI
2008-11-20 9:03 ` Izik Eidus
2008-11-20 9:13 ` Izik Eidus
2008-11-20 9:44 ` Ryota OZAKI
2008-11-28 12:57 ` Dmitri Monakhov
2008-11-28 13:51 ` Alan Cox
-- strict thread matches above, loose matches on Subject: below --
2008-11-11 13:21 [PATCH 0/4] ksm - dynamic page sharing driver for linux Izik Eidus
2008-11-11 13:21 ` [PATCH 1/4] rmap: add page_wrprotect() function, Izik Eidus, Izik Eidus
2008-11-11 13:21 ` [PATCH 2/4] Add replace_page(), change the mapping of pte from one page into another Izik Eidus, Izik Eidus
2008-11-11 13:21 ` [PATCH 3/4] add ksm kernel shared memory driver Izik Eidus, Izik Eidus
2008-11-11 20:38 ` Andrew Morton
2008-11-11 22:03 ` Andrea Arcangeli
2008-11-11 22:03 ` Jonathan Corbet
2008-11-11 22:17 ` Izik Eidus
2008-11-11 22:25 ` Jonathan Corbet
2008-11-11 22:31 ` Izik Eidus
2008-11-11 22:30 ` Jonathan Corbet
2008-11-11 22:38 ` Izik Eidus
2008-11-11 23:02 ` Izik Eidus
2008-11-11 23:03 ` Andrea Arcangeli
2008-11-11 22:49 ` Avi Kivity
2008-11-11 22:40 ` Valdis.Kletnieks
2008-11-13 6:13 ` Eric Rannaud
2008-11-11 22:43 ` Avi Kivity
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