1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
|
#!/usr/bin/perl -w
# libguestfs
# Copyright (C) 2018 Red Hat Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
# From painful experience we know that changes to the kernel can
# suddenly change the maximum number of disks we can add to the
# appliance. This script uses a simple binary search to find the
# current maximum.
#
# To test different kernels you may want to do:
# rm -rf /var/tmp/.guestfs-*
# export SUPERMIN_KERNEL=/boot/vmlinuz-...
# export SUPERMIN_MODULES=/lib/modules/...
# ./max-disks.pl
#
# See also:
# https://bugzilla.redhat.com/show_bug.cgi?id=1478201#c4
use strict;
use Sys::Guestfs;
$| = 1;
my $low = 1;
my $high = 2048; # Will never test higher than this.
my $mid = 1024;
# Get the kernel under test.
my $g = Sys::Guestfs->new ();
$g->launch ();
my %kernel = $g->utsname;
$g->close ();
sub test_mid
{
my ($ret, %k);
eval {
my $g = Sys::Guestfs->new ();
for (my $i = 0; $i < $mid; ++$i) {
$g->add_drive_scratch (1024*1024);
}
$g->launch ();
%k = $g->utsname;
$g->shutdown ();
};
if ($@) {
printf ("%d => bad\n", $mid);
$ret = 0;
}
else {
printf ("%d => good\n", $mid);
$ret = 1;
}
die "kernel version changed during test!\n"
if exists $k{uts_release} && $k{uts_release} ne $kernel{uts_release};
return $ret;
}
for (;;) {
if (test_mid ()) {
# good, so try higher
$low = $mid;
}
else {
# bad, so try lower
$high = $mid;
}
$mid = int (($high+$low) / 2);
if ($mid == $high || $mid == $low) {
printf("kernel: %s %s (%s)\n",
$kernel{uts_sysname}, $kernel{uts_release},
$kernel{uts_machine});
# +1 because of the appliance disk.
printf ("max disks = %d\n", $mid+1);
exit 0;
}
}
|
