From: Izik Eidus <ieidus@redhat.com>
To: Rik van Riel <riel@surriel.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
aarcange@redhat.com, chrisw@redhat.com, alan@lxorguk.ukuu.org.uk,
device@lanana.org, linux-mm@kvack.org, hugh@veritas.com,
nickpiggin@yahoo.com.au
Subject: Re: [PATCH 1/6] ksm: limiting the num of mem regions user can register per fd.
Date: Sun, 03 May 2009 12:06:30 +0300 [thread overview]
Message-ID: <49FD5E96.6060301@redhat.com> (raw)
In-Reply-To: <20090502220829.392b7ff9@riellaptop.surriel.com>
Rik van Riel wrote:
> On Sun, 3 May 2009 01:16:07 +0300
> Izik Eidus <ieidus@redhat.com> wrote:
>
>
>> Right now user can open /dev/ksm fd and register unlimited number of
>> regions, such behavior may allocate unlimited amount of kernel memory
>> and get the whole host into out of memory situation.
>>
>
> How many times can a process open /dev/ksm?
>
> If a process can open /dev/ksm a thousand times and then
> register 1000 regions through each file descriptor, this
> patch does not help all that much...
>
>
The idea is that the limitation is now on the maximum file descriptors
user can open.
So for each such file descriptor user can open 1024 structures that are
just few bytes each.
The whole propose of this patch is to avoid while (1) {
IOCTL(REGISTER_MEMORY_REGION) } and oom the host.
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next prev parent reply other threads:[~2009-05-03 9:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-05-02 22:16 [PATCH 0/6] ksm changes Izik Eidus
2009-05-02 22:16 ` [PATCH 1/6] ksm: limiting the num of mem regions user can register per fd Izik Eidus
2009-05-02 22:16 ` [PATCH 2/6] ksm: dont allow overlap memory addresses registrations Izik Eidus
2009-05-02 22:16 ` [PATCH 3/6] ksm: change the KSM_REMOVE_MEMORY_REGION ioctl Izik Eidus
2009-05-02 22:16 ` [PATCH 4/6] ksm: change the prot handling to use the generic helper functions Izik Eidus
2009-05-02 22:16 ` [PATCH 5/6] ksm: build system make it compile for all archs Izik Eidus
2009-05-02 22:16 ` [PATCH 6/6] ksm: use another miscdevice minor number Izik Eidus
2009-05-04 19:43 ` [PATCH 3/6] ksm: change the KSM_REMOVE_MEMORY_REGION ioctl Hugh Dickins
2009-05-04 20:37 ` Izik Eidus
2009-05-03 2:08 ` [PATCH 1/6] ksm: limiting the num of mem regions user can register per fd Rik van Riel
2009-05-03 9:06 ` Izik Eidus [this message]
2009-05-03 2:08 ` Rik van Riel
-- strict thread matches above, loose matches on Subject: below --
2009-05-04 22:25 [PATCH 0/6] ksm changes (v2) Izik Eidus
2009-05-04 22:25 ` [PATCH 1/6] ksm: limiting the num of mem regions user can register per fd Izik Eidus
2009-05-06 0:40 ` Rik van Riel
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