From: Anthony Liguori <anthony@codemonkey.ws>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Izik Eidus <ieidus@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, avi@redhat.com, chrisw@redhat.com,
riel@redhat.com, jeremy@goop.org, mtosatti@redhat.com,
hugh@veritas.com, corbet@lwn.net, yaniv@redhat.com,
dmonakhov@openvz.org
Subject: Re: [PATCH 4/4] add ksm kernel shared memory driver.
Date: Tue, 31 Mar 2009 10:54:57 -0500 [thread overview]
Message-ID: <49D23CD1.9090208@codemonkey.ws> (raw)
In-Reply-To: <20090331151845.GT9137@random.random>
Andrea Arcangeli wrote:
> On Tue, Mar 31, 2009 at 10:09:24AM -0500, Anthony Liguori wrote:
>
>> I don't think the registering of ram should be done via sysfs. That would
>> be a pretty bad interface IMHO. But I do think the functionality that
>> ksmctl provides along with the security issues I mentioned earlier really
>> suggest that there ought to be a separate API for control vs. registration
>> and that control API would make a lot of sense as a sysfs API.
>>
>> If you wanted to explore alternative APIs for registration, madvise() seems
>> like the obvious candidate to me.
>>
>> madvise(start, size, MADV_SHARABLE) seems like a pretty obvious API to me.
>>
>
> madvise to me would sound appropriate, only if ksm would be always-in,
> which is not the case as it won't even be built if it's configured to
> N.
>
You can still disable ksm and simply return ENOSYS for the MADV_ flag.
You could even keep it as a module if you liked by separating the
madvise bits from the ksm bits. The madvise() bits could just provide
the tracking infrastructure for determine which vmas were currently
marked as sharable.
You could then have ksm as loadable module that consumed that interface
to then perform scanning.
> Besides madvise is sus covered syscall, and this is linux specific detail.
>
A number of MADV_ flags are Linux specific (like MADV_DOFORK/MADV_DONTFORK).
Regards,
Anthony Liguori
WARNING: multiple messages have this Message-ID (diff)
From: Anthony Liguori <anthony@codemonkey.ws>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Izik Eidus <ieidus@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, avi@redhat.com, chrisw@redhat.com,
riel@redhat.com, jeremy@goop.org, mtosatti@redhat.com,
hugh@veritas.com, corbet@lwn.net, yaniv@redhat.com,
dmonakhov@openvz.org
Subject: Re: [PATCH 4/4] add ksm kernel shared memory driver.
Date: Tue, 31 Mar 2009 10:54:57 -0500 [thread overview]
Message-ID: <49D23CD1.9090208@codemonkey.ws> (raw)
In-Reply-To: <20090331151845.GT9137@random.random>
Andrea Arcangeli wrote:
> On Tue, Mar 31, 2009 at 10:09:24AM -0500, Anthony Liguori wrote:
>
>> I don't think the registering of ram should be done via sysfs. That would
>> be a pretty bad interface IMHO. But I do think the functionality that
>> ksmctl provides along with the security issues I mentioned earlier really
>> suggest that there ought to be a separate API for control vs. registration
>> and that control API would make a lot of sense as a sysfs API.
>>
>> If you wanted to explore alternative APIs for registration, madvise() seems
>> like the obvious candidate to me.
>>
>> madvise(start, size, MADV_SHARABLE) seems like a pretty obvious API to me.
>>
>
> madvise to me would sound appropriate, only if ksm would be always-in,
> which is not the case as it won't even be built if it's configured to
> N.
>
You can still disable ksm and simply return ENOSYS for the MADV_ flag.
You could even keep it as a module if you liked by separating the
madvise bits from the ksm bits. The madvise() bits could just provide
the tracking infrastructure for determine which vmas were currently
marked as sharable.
You could then have ksm as loadable module that consumed that interface
to then perform scanning.
> Besides madvise is sus covered syscall, and this is linux specific detail.
>
A number of MADV_ flags are Linux specific (like MADV_DOFORK/MADV_DONTFORK).
Regards,
Anthony Liguori
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next prev parent reply other threads:[~2009-03-31 15:55 UTC|newest]
Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-30 23:59 [PATCH 0/4] ksm - dynamic page sharing driver for linux Izik Eidus
2009-03-30 23:59 ` Izik Eidus
2009-03-30 23:59 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-03-30 23:59 ` Izik Eidus
2009-03-30 23:59 ` [PATCH 2/4] add page_wrprotect(): write protecting page Izik Eidus
2009-03-30 23:59 ` Izik Eidus
2009-03-30 23:59 ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Izik Eidus
2009-03-30 23:59 ` Izik Eidus
2009-03-30 23:59 ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-03-30 23:59 ` Izik Eidus
2009-03-31 2:12 ` Anthony Liguori
2009-03-31 2:12 ` Anthony Liguori
2009-03-31 12:24 ` Izik Eidus
2009-03-31 12:24 ` Izik Eidus
2009-03-31 13:31 ` Anthony Liguori
2009-03-31 13:31 ` Anthony Liguori
2009-03-31 14:25 ` Andrea Arcangeli
2009-03-31 14:25 ` Andrea Arcangeli
2009-03-31 14:37 ` Anthony Liguori
2009-03-31 14:37 ` Anthony Liguori
2009-03-31 15:02 ` Andrea Arcangeli
2009-03-31 15:02 ` Andrea Arcangeli
2009-03-31 15:09 ` Anthony Liguori
2009-03-31 15:09 ` Anthony Liguori
2009-03-31 15:18 ` Andrea Arcangeli
2009-03-31 15:18 ` Andrea Arcangeli
2009-03-31 15:54 ` Anthony Liguori [this message]
2009-03-31 15:54 ` Anthony Liguori
2009-03-31 16:25 ` Andrea Arcangeli
2009-03-31 16:25 ` Andrea Arcangeli
2009-03-31 16:51 ` Anthony Liguori
2009-03-31 16:51 ` Anthony Liguori
2009-03-31 17:11 ` Andrea Arcangeli
2009-03-31 17:11 ` Andrea Arcangeli
2009-04-01 22:54 ` Izik Eidus
2009-04-01 22:54 ` Izik Eidus
2009-04-02 0:31 ` Anthony Liguori
2009-04-02 0:31 ` Anthony Liguori
2009-04-02 0:48 ` Chris Wright
2009-04-02 0:48 ` Chris Wright
2009-04-02 1:22 ` Chris Wright
2009-04-02 1:22 ` Chris Wright
2009-04-02 2:36 ` Anthony Liguori
2009-04-02 2:36 ` Anthony Liguori
2009-04-02 5:31 ` [PATCH 5/4] update ksm userspace interfaces Chris Wright
2009-04-02 5:31 ` Chris Wright
2009-04-02 13:32 ` Izik Eidus
2009-04-02 13:32 ` Izik Eidus
2009-04-02 15:20 ` Chris Wright
2009-04-02 15:20 ` Chris Wright
2009-04-02 15:56 ` Chris Wright
2009-04-02 15:56 ` Chris Wright
2009-04-02 15:55 ` Izik Eidus
2009-04-02 15:55 ` Izik Eidus
2009-04-03 10:16 ` Gerd Hoffmann
2009-04-03 10:16 ` Gerd Hoffmann
2009-04-03 10:49 ` Izik Eidus
2009-04-03 10:49 ` Izik Eidus
2009-04-03 11:08 ` Gerd Hoffmann
2009-04-03 11:08 ` Gerd Hoffmann
2009-04-03 16:22 ` Chris Wright
2009-04-03 16:22 ` Chris Wright
2009-04-02 14:41 ` Andrea Arcangeli
2009-04-02 14:41 ` Andrea Arcangeli
2009-04-02 15:12 ` Chris Wright
2009-04-02 15:12 ` Chris Wright
2009-04-02 15:25 ` Andrea Arcangeli
2009-04-02 15:25 ` Andrea Arcangeli
2009-04-02 5:48 ` [PATCH 4/4 alternative userspace] add ksm kernel shared memory driver Chris Wright
2009-04-02 5:48 ` Chris Wright
2009-04-02 5:57 ` Bert Wesarg
2009-04-02 5:57 ` Bert Wesarg
2009-04-02 5:57 ` Bert Wesarg
2009-04-02 5:59 ` Chris Wright
2009-04-02 5:59 ` Chris Wright
2009-04-02 6:00 ` Bert Wesarg
2009-04-02 6:00 ` Bert Wesarg
2009-04-02 7:09 ` Avi Kivity
2009-04-02 7:09 ` Avi Kivity
2009-04-02 7:24 ` [PATCH 4/4] " Avi Kivity
2009-04-02 7:24 ` Avi Kivity
2009-04-02 9:38 ` Andrea Arcangeli
2009-04-02 9:38 ` Andrea Arcangeli
2009-04-02 11:23 ` Izik Eidus
2009-04-02 11:23 ` Izik Eidus
2009-03-31 2:15 ` KAMEZAWA Hiroyuki
2009-03-31 2:15 ` KAMEZAWA Hiroyuki
2009-03-31 12:21 ` Izik Eidus
2009-03-31 12:21 ` Izik Eidus
2009-03-31 23:57 ` KAMEZAWA Hiroyuki
2009-03-31 23:57 ` KAMEZAWA Hiroyuki
2009-04-01 17:28 ` Izik Eidus
2009-04-01 17:28 ` Izik Eidus
2009-03-31 20:52 ` Andrea Arcangeli
2009-03-31 20:52 ` Andrea Arcangeli
2009-03-31 1:42 ` [PATCH 0/4] ksm - dynamic page sharing driver for linux Anthony Liguori
2009-03-31 1:42 ` Anthony Liguori
2009-03-31 12:33 ` Izik Eidus
2009-03-31 12:33 ` Izik Eidus
2009-04-02 19:22 ` Jesper Juhl
2009-04-02 19:22 ` Jesper Juhl
2009-04-02 19:38 ` Izik Eidus
2009-04-02 19:38 ` Izik Eidus
2009-04-02 19:39 ` Chris Wright
2009-04-02 19:39 ` Chris Wright
2009-04-02 19:49 ` Jesper Juhl
2009-04-02 19:49 ` Jesper Juhl
2009-04-04 14:35 [PATCH 0/4] ksm - dynamic page sharing driver for linux v2 Izik Eidus
2009-04-04 14:35 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-04-04 14:35 ` [PATCH 2/4] add page_wrprotect(): write protecting page Izik Eidus
2009-04-04 14:35 ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Izik Eidus
2009-04-04 14:35 ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-04-04 14:35 ` Izik Eidus
2009-04-06 9:13 ` Andrey Panin
2009-04-06 9:13 ` Andrey Panin
2009-04-06 10:58 ` Izik Eidus
2009-04-06 10:58 ` Izik Eidus
2009-04-06 10:58 ` Izik Eidus
2009-04-09 3:58 [PATCH 0/4] ksm - dynamic page sharing driver for linux v3 Izik Eidus
2009-04-09 3:58 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-04-09 3:58 ` [PATCH 2/4] add page_wrprotect(): write protecting page Izik Eidus
2009-04-09 3:58 ` [PATCH 3/4] add replace_page(): change the page pte is pointing to Izik Eidus
2009-04-09 3:58 ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-04-09 3:58 ` Izik Eidus
2009-04-14 22:09 ` Andrew Morton
2009-04-14 22:09 ` Andrew Morton
2009-04-14 22:09 ` Andrew Morton
2009-04-15 22:37 ` Izik Eidus
2009-04-15 22:37 ` Izik Eidus
2009-04-15 22:50 ` Andrew Morton
2009-04-15 22:50 ` Andrew Morton
2009-04-15 23:21 ` Andrea Arcangeli
2009-04-15 23:21 ` Andrea Arcangeli
2009-04-16 0:43 ` Jeremy Fitzhardinge
2009-04-16 0:43 ` Jeremy Fitzhardinge
2009-04-16 0:57 ` Izik Eidus
2009-04-16 0:57 ` Izik Eidus
2009-04-16 11:39 ` Andrea Arcangeli
2009-04-16 11:39 ` Andrea Arcangeli
2009-04-16 16:08 ` Jeremy Fitzhardinge
2009-04-16 16:08 ` Jeremy Fitzhardinge
2009-04-18 14:58 ` Andrea Arcangeli
2009-04-18 14:58 ` Andrea Arcangeli
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