On Mon, Jan 14, 2008 at 06:46:49AM -0800, Bryan Cantrill wrote:
> > So, I failed to understand the modules loading needs 4 minutes.
>
> Yes, this is definitely fishy. Is this a highly memory constrained system?
> If you "modunload -i 0" enough times to get dtrace(7D) unloaded (that
> is, "dtrace" doesn't appear in modinfo), does it again take 4 minutes?
> As you can imagine, it's a little tough to investigate this problem because
> we can't use DTrace to do it! ;)
Kicking the dtrace kernel module out is a bit trickier than back in the day
due to this bug:
6282201 USDT probes can prevent dtrace(7D) from being unloaded
In order to unload dtrace, you'll need to make sure there are no processes
with USDT probes. This is done as part of one of the DTrace test suite
tests:
--8<-- usr/src/cmd/dtrace/test/tst/common/predicates/tst.predcache.ksh --8<--
28 unload()
29 {
30 #
31 # Get the list of services whose processes have USDT probes. Ideally
32 # it would be possible to unload the fasttrap provider while USDT
33 # probes exist -- once that fix is integrated, this hack can go away
34 # We create two lists -- one of regular SMF services and one of legacy
35 # services -- since each must be enabled and disabled using a specific
36 # mechanism.
37 #
38 pids=$(dtrace -l | \
39 perl -ne 'print "$1\n" if (/^\s*\S+\s+\S*\D(\d+)\s+/);' | \
40 sort | uniq | tr '\n' ',')
41
42 ctids=$(ps -p $pids -o ctid | tail +2 | sort | uniq)
43 svcs=
44 lrcs=
45
46 for ct in $ctids
47 do
48 line=$(svcs -o fmri,ctid | grep " $ct\$")
49 svc=$(echo $line | cut -d' ' -f1)
50
51 if [[ $(svcs -Ho STA $svc) == "LRC" ]]; then
52 lrc=$(svcs -Ho SVC $svc | tr _ '?')
53 lrcs="$lrcs $lrc"
54 else
55 svcs="$svcs $svc"
56 fi
57 done
58
59 for svc in $svcs
60 do
61 svcadm disable -ts $svc
62 done
63
64 for lrc in $lrcs
65 do
66 #
67 # Does it seem a little paternalistic that lsvcrun requires
68 # this environment variable to be set? I'd say so...
69 #
70 SMF_RESTARTER=svc:/system/svc/restarter:default \
71 /lib/svc/bin/lsvcrun $lrc stop
72 done
73
74 modunload -i 0
75 modunload -i 0
76 modunload -i 0
77 modinfo | grep dtrace
78 success=$?
79
80 for svc in $svcs
81 do
82 svcadm enable -ts $svc
83 done
84
85 for lrc in $lrcs
86 do
87 SMF_RESTARTER=svc:/system/svc/restarter:default \
88 /lib/svc/bin/lsvcrun $lrc start
89 done
90
91 if [ ! $success ]; then
92 echo $tst: could not unload dtrace
93 exit 1
94 fi
95 }
--8<-- usr/src/cmd/dtrace/test/tst/common/predicates/tst.predcache.ksh --8<--
Adam
--
Adam Leventhal, FishWorks http://blogs.sun.com/ahl
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