From: Izik Eidus <ieidus@redhat.com>
To: Chris Wright <chrisw@redhat.com>
Cc: Anthony Liguori <anthony@codemonkey.ws>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
linux-mm@kvack.org, avi@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 5/4] update ksm userspace interfaces
Date: Thu, 02 Apr 2009 16:32:20 +0300 [thread overview]
Message-ID: <49D4BE64.8020508@redhat.com> (raw)
In-Reply-To: <20090402053114.GF1117@x200.localdomain>
Chris Wright wrote:
> * Anthony Liguori (anthony@codemonkey.ws) wrote:
>
>> Using an interface like madvise() would force the issue to be dealt with
>> properly from the start :-)
>>
>
> Yeah, I'm not at all opposed to it.
>
> This updates to madvise for register and sysfs for control.
>
> madvise issues:
> - MADV_SHAREABLE
> - register only ATM, can add MADV_UNSHAREABLE to allow an app to proactively
> unregister, but need a cleanup when ->mm goes away via exit/exec
> - will register a region per vma, should probably push the whole thing
> into vma rather than keep [mm,addr,len] tuple in ksm
>
>
The main problem that ksm will face when removing the fd interface is:
right now when you register memory into ksm, you open fd, and then ksm
do get_task_mm(), we will do mmput when the file will be closed
(note that this doesnt mean that if you fork and not close the fd the
memory wont go away...., get_task_mm() doesnt protect the vmas inside
the mm strcture and therefore they will be able to get removed)
So if we move into madvice and we remove the get_task_mm() usage, we
will have to add notification to exit_mm() so ksm will know it should
stop using this mm strcture, and drop it from all the trees data...
Is this what we want?
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next prev parent reply other threads:[~2009-04-02 13:32 UTC|newest]
Thread overview: 53+ 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 ` [PATCH 1/4] MMU_NOTIFIERS: add set_pte_at_notify() Izik Eidus
2009-03-30 23:59 ` [PATCH 2/4] add page_wrprotect(): write protecting page 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 ` [PATCH 4/4] add ksm kernel shared memory driver Izik Eidus
2009-03-31 2:12 ` Anthony Liguori
2009-03-31 12:24 ` Izik Eidus
2009-03-31 13:31 ` Anthony Liguori
2009-03-31 14:25 ` Andrea Arcangeli
2009-03-31 14:37 ` Anthony Liguori
2009-03-31 15:02 ` Andrea Arcangeli
2009-03-31 15:09 ` Anthony Liguori
2009-03-31 15:18 ` Andrea Arcangeli
2009-03-31 15:54 ` Anthony Liguori
2009-03-31 16:25 ` Andrea Arcangeli
2009-03-31 16:51 ` Anthony Liguori
2009-03-31 17:11 ` Andrea Arcangeli
2009-04-01 22:54 ` Izik Eidus
2009-04-02 0:31 ` Anthony Liguori
2009-04-02 0:48 ` Chris Wright
2009-04-02 1:22 ` Chris Wright
2009-04-02 2:36 ` Anthony Liguori
2009-04-02 5:31 ` [PATCH 5/4] update ksm userspace interfaces Chris Wright
2009-04-02 13:32 ` Izik Eidus [this message]
2009-04-02 15:20 ` Chris Wright
2009-04-02 15:56 ` Chris Wright
2009-04-02 15:55 ` Izik Eidus
2009-04-03 10:16 ` Gerd Hoffmann
2009-04-03 10:49 ` Izik Eidus
2009-04-03 11:08 ` Gerd Hoffmann
2009-04-03 16:22 ` Chris Wright
2009-04-02 14:41 ` Andrea Arcangeli
2009-04-02 15:12 ` Chris Wright
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 5:57 ` Bert Wesarg
2009-04-02 5:59 ` Chris Wright
2009-04-02 6:00 ` Bert Wesarg
2009-04-02 7:09 ` Avi Kivity
2009-04-02 7:24 ` [PATCH 4/4] " Avi Kivity
2009-04-02 9:38 ` Andrea Arcangeli
2009-04-02 11:23 ` Izik Eidus
2009-03-31 2:15 ` KAMEZAWA Hiroyuki
2009-03-31 12:21 ` Izik Eidus
2009-03-31 23:57 ` KAMEZAWA Hiroyuki
2009-04-01 17:28 ` Izik Eidus
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 12:33 ` Izik Eidus
2009-04-02 19:22 ` Jesper Juhl
2009-04-02 19:38 ` Izik Eidus
2009-04-02 19:39 ` Chris Wright
2009-04-02 19:49 ` Jesper Juhl
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