WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] Size limit on extra argument to xm create

To: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] Size limit on extra argument to xm create
From: Mick Jordan <Mick.Jordan@xxxxxxx>
Date: Fri, 09 Oct 2009 12:57:57 -0700
Delivery-date: Fri, 09 Oct 2009 12:58:47 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4AA8772C.5060601@xxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <4AA8772C.5060601@xxxxxxx>
Reply-to: Mick.Jordan@xxxxxxx
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 2.0.0.21 (X11/20090311)
On 09/ 9/09 08:49 PM, Mick Jordan wrote:
Experimentally there seems to be a 1024 byte limit on the size of the extra parameter to xm create (shades of csh!).

Before I dig in to the code, I'm thought I'd check if this a limit in xm or a more fundamental limit in the Xen guest interface. I can imagine a hard limit of a page in the latter case, but that would be a lot better than 1024.
I was too hasty in attributing this to problems with shell variable length limits. There does seem to be a Xen limit of 1024 characters for the "extra" argument to "xm create", as shown below. The cmd_line value passed to the guest is truncated at 1024. So my question above holds.

# xm create -c xmconfigs/domain_config_generic extra="-XX:+UseVirtualMemory -cp /guestvm/image/GuestVM/bin test.java.lang.ArgsTest really_quite_a_long_argument_1 really_quite_a_long_argument_2 really_quite_a_long_argument_3 really_quite_a_long_argument_4 really_quite_a_long_argument_5 really_quite_a_long_argument_6 really_quite_a_long_argument_7 really_quite_a_long_argument_8 really_quite_a_long_argument_9 really_quite_a_long_argument_10 really_quite_a_long_argument_11 really_quite_a_long_argument_12 really_quite_a_long_argument_13 really_quite_a_long_argument_14 really_quite_a_long_argument_15 really_quite_a_long_argument_16 really_quite_a_long_argument_17 really_quite_a_long_argument_18 really_quite_a_long_argument_19 really_quite_a_long_argument_20 really_quite_a_long_argument_21 really_quite_a_long_argument_22 really_quite_a_long_argument_23 really_quite_a_long_argument_24 really_quite_a_long_argument_25 really_quite_a_long_argument_26 really_quite_a_long_argument_27 really_quite_a_long_argument_28 really_quite_a_long_argument_29 really_quite_a_long_argument_30 really_quite_a_long_argument_40 really_quite_a_long_argument_41 really_quite_a_long_argument_42 really_quite_a_long_argument_43 really_quite_a_long_argument_44 really_quite_a_long_argument_45 really_quite_a_long_argument_46 really_quite_a_long_argument_47 really_quite_a_long_argument_48 really_quite_a_long_argument_49 really_quite_a_long_argument_50 really_quite_a_long_argument_51 really_quite_a_long_argument_52 really_quite_a_long_argument_53 really_quite_a_long_argument_54 really_quite_a_long_argument_55 really_quite_a_long_argument_56 really_quite_a_long_argument_57 really_quite_a_long_argument_58 really_quite_a_long_argument_59 really_quite_a_long_argument_60"

Using config file "./xmconfigs/domain_config_generic".
Started domain GuestVM-mjj
argc 35
 0 GuestVM-mjj
 1 -XX:+UseVirtualMemory
 2 -cp
 3 /guestvm/image/GuestVM/bin
 4 test.java.lang.ArgsTest
 5 really_quite_a_long_argument_1
 6 really_quite_a_long_argument_2
 7 really_quite_a_long_argument_3
 8 really_quite_a_long_argument_4
 9 really_quite_a_long_argument_5
 10 really_quite_a_long_argument_6
 11 really_quite_a_long_argument_7
 12 really_quite_a_long_argument_8
 13 really_quite_a_long_argument_9
 14 really_quite_a_long_argument_10
 15 really_quite_a_long_argument_11
 16 really_quite_a_long_argument_12
 17 really_quite_a_long_argument_13
 18 really_quite_a_long_argument_14
 19 really_quite_a_long_argument_15
 20 really_quite_a_long_argument_16
 21 really_quite_a_long_argument_17
 22 really_quite_a_long_argument_18
 23 really_quite_a_long_argument_19
 24 really_quite_a_long_argument_20
 25 really_quite_a_long_argument_21
 26 really_quite_a_long_argument_22
 27 really_quite_a_long_argument_23
 28 really_quite_a_long_argument_24
 29 really_quite_a_long_argument_25
 30 really_quite_a_long_argument_26
 31 really_quite_a_long_argument_27
 32 really_quite_a_long_argument_28
 33 really_quite_a_long_argument_29
 34 really_quite_a_long_argumen
#


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel