On 2016/11/10 at 14:25, Dave Young wrote:
> On 11/10/16 at 01:56pm, Xunlei Pang wrote:
>> On 2016/11/10 at 10:45, Dave Young wrote:
>>> On 11/09/16 at 06:34pm, Xunlei Pang wrote:
>>>> On 2016/11/09 at 16:33, Dave Young wrote:
>>>>> Hi, Xunlei
>>>>> On 11/07/16 at 01:34pm, Xunlei Pang wrote:
>>>>>> Extend "rd.memdebug" to "4", and "make_trace_mem" to "4+:komem".
>>>>>> Add new "cleanup_trace_mem" to cleanup the trace if active.
>>>>>>
>>>>>> Signed-off-by: Xunlei Pang <xlpang@xxxxxxxxxx>
>>>>>> ---
>>>>>> modules.d/98dracut-systemd/dracut-cmdline.sh | 2 +-
>>>>>> modules.d/98dracut-systemd/dracut-pre-mount.sh | 2 +-
>>>>>> modules.d/98dracut-systemd/dracut-pre-pivot.sh | 3 ++-
>>>>>> modules.d/98dracut-systemd/dracut-pre-trigger.sh | 2 +-
>>>>>> modules.d/99base/dracut-lib.sh | 13 ++++++++++++-
>>>>>> modules.d/99base/init.sh | 9 +++++----
>>>>>> modules.d/99base/module-setup.sh | 1 +
>>>>>> 7 files changed, 23 insertions(+), 9 deletions(-)
>>>>>>
>>>>>> diff --git a/modules.d/98dracut-systemd/dracut-cmdline.sh b/modules.d/98dracut-systemd/dracut-cmdline.sh
>>>>>> index 6c6ee02..bff9435 100755
>>>>>> --- a/modules.d/98dracut-systemd/dracut-cmdline.sh
>>>>>> +++ b/modules.d/98dracut-systemd/dracut-cmdline.sh
>>>>>> @@ -42,7 +42,7 @@ export root
>>>>>> export rflags
>>>>>> export fstype
>>>>>>
>>>>>> -make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab'
>>>>>> +make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab' '4+:komem'
>>>>>> # run scriptlets to parse the command line
>>>>>> getarg 'rd.break=cmdline' -d 'rdbreak=cmdline' && emergency_shell -n cmdline "Break before cmdline"
>>>>>> source_hook cmdline
>>>>>> diff --git a/modules.d/98dracut-systemd/dracut-pre-mount.sh b/modules.d/98dracut-systemd/dracut-pre-mount.sh
>>>>>> index ae51128..a3b9d29 100755
>>>>>> --- a/modules.d/98dracut-systemd/dracut-pre-mount.sh
>>>>>> +++ b/modules.d/98dracut-systemd/dracut-pre-mount.sh
>>>>>> @@ -8,7 +8,7 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>>>>>>
>>>>>> source_conf /etc/conf.d
>>>>>>
>>>>>> -make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab'
>>>>>> +make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>>> # pre pivot scripts are sourced just before we doing cleanup and switch over
>>>>>> # to the new root.
>>>>>> getarg 'rd.break=pre-mount' 'rdbreak=pre-mount' && emergency_shell -n pre-mount "Break pre-mount"
>>>>>> diff --git a/modules.d/98dracut-systemd/dracut-pre-pivot.sh b/modules.d/98dracut-systemd/dracut-pre-pivot.sh
>>>>>> index cc70e3c..dc9a250 100755
>>>>>> --- a/modules.d/98dracut-systemd/dracut-pre-pivot.sh
>>>>>> +++ b/modules.d/98dracut-systemd/dracut-pre-pivot.sh
>>>>>> @@ -8,12 +8,13 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>>>>>>
>>>>>> source_conf /etc/conf.d
>>>>>>
>>>>>> -make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab'
>>>>>> +make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>>> # pre pivot scripts are sourced just before we doing cleanup and switch over
>>>>>> # to the new root.
>>>>>> getarg 'rd.break=pre-pivot' 'rdbreak=pre-pivot' && emergency_shell -n pre-pivot "Break pre-pivot"
>>>>>> source_hook pre-pivot
>>>>>>
>>>>>> +cleanup_trace_mem
>>>>>> # pre pivot cleanup scripts are sourced just before we switch over to the new root.
>>>>>> getarg 'rd.break=cleanup' 'rdbreak=cleanup' && emergency_shell -n cleanup "Break cleanup"
>>>>>> source_hook cleanup
>>>>>> diff --git a/modules.d/98dracut-systemd/dracut-pre-trigger.sh b/modules.d/98dracut-systemd/dracut-pre-trigger.sh
>>>>>> index ac1ec36..7cd821e 100755
>>>>>> --- a/modules.d/98dracut-systemd/dracut-pre-trigger.sh
>>>>>> +++ b/modules.d/98dracut-systemd/dracut-pre-trigger.sh
>>>>>> @@ -8,7 +8,7 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
>>>>>>
>>>>>> source_conf /etc/conf.d
>>>>>>
>>>>>> -make_trace_mem "hook pre-trigger" "1:shortmem" "2+:mem" "3+:slab"
>>>>>> +make_trace_mem "hook pre-trigger" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>>>
>>>>>> source_hook pre-trigger
>>>>>>
>>>>>> diff --git a/modules.d/99base/dracut-lib.sh b/modules.d/99base/dracut-lib.sh
>>>>>> index 060b3fe..2a29bbc 100755
>>>>>> --- a/modules.d/99base/dracut-lib.sh
>>>>>> +++ b/modules.d/99base/dracut-lib.sh
>>>>>> @@ -1206,12 +1206,20 @@ are_lists_eq() {
>>>>>>
>>>>>> setmemdebug() {
>>>>>> if [ -z "$DEBUG_MEM_LEVEL" ]; then
>>>>>> - export DEBUG_MEM_LEVEL=$(getargnum 0 0 3 rd.memdebug)
>>>>>> + export DEBUG_MEM_LEVEL=$(getargnum 0 0 4 rd.memdebug)
>>>>>> fi
>>>>>> }
>>>>>>
>>>>>> setmemdebug
>>>>>>
>>>>>> +cleanup_trace_mem()
>>>>>> +{
>>>>>> + # tracekomem based on kernel trace needs cleanup after use.
>>>>>> + if [[ $DEBUG_MEM_LEVEL -eq 4 ]]; then
>>>>> It does not work if out of tree modules add it to DEBUG_MEM_LEVEL <
>>>>> 4, sounds bad to hard code it. It seems good to do the cleanup without
>>>>> the check.
>>>> Hi Dave,
>>>>
>>>> I can't understand why out of tree modules would do this, however we can't
>>>> guarantee that even after removing the hard code condition. Let's say, out of
>>>> tree modules use it at the very beginning and disable it quite after pre-pivot
>>>> with no "rd.memdebug", then the trace will be disabled at pre-pivot which will
>>>> cause confusion(or unnoticed data loss) for the out of tree modules.
>>> It should be a corner case, but use a fixed DEBUG_MEM_LEVEL sounds
>>> still not good, we designed the DEBUG_MEM_LEVEL but the design does not
>>> limit each facility to force connect to one of the levels.
>> Hi Dave,
>>
>> Maybe I didn't quite catch what you meant.
>>
>> The current implementation only uses level 4 for komem using '4+:komem', do you mean
>> some out of tree module adds something like: make_trace_mem '2+: komem'? If so, it contradicts
>> the "rd.memdebug" manpage described in PATCH3/3.
> Yes, it is what I thought about.
OK, but the current design of "rd.memdebug" does use the hard-coded make_trace_mem,
for example, you can't output slab information below level 3.
In order to stay consistent with previous behavior described in "man dracut.cmdline",
better not add something like make_trace_mem '2:slab' for "rd.memdebug" unless use
it as your private debugging and be aware of all the details.
Thus I prefer to keep the hard-coded DEBUG_MEM_LEVEL.
>
>>> But I have no strong opinion, I can live with it..
>>>
>>>>> There is another concern, if someone manually enables tracing in kernel
>>>>> cmdline then we should not cleanup, maybe we can print a warning msg
>>>>> and do not do our tracing at all.
>>>>>
>>>>> For cleanup and prepare ideally we can do something like make_trace_mem,
>>>>> like prepare_trace_mem and cleanup_trace_mem, for each facility if there
>>>>> is a prepare/cleanup function then call it. But for the time being it
>>>>> may not worth to add the complexity. What do you think?
>>>> Because the script does cleanup iff is_trace_ready() returns true when
>>>> both tracing is on and the events match, I think it is safe enough that
>>>> we don't need to worry about the wrong cleanup if we really want to do this:
>>>> is_trace_ready() {
>>>> local trace_base want_events current_events
>>>>
>>>> trace_base=$(get_trace_base)
>>>> ! [[ -f "$trace_base/tracing/trace" ]] && return 1
>>>>
>>>> [[ $(cat $trace_base/tracing/tracing_on) = 0 ]] && return 1
>>>>
>>>> # Also check if trace events were properly setup.
>>>> want_events=$(get_want_events)
>>>> current_events=$(echo $(cat $trace_base/tracing/set_event))
>>>> [[ "$current_events" != "$want_events" ]] && return 1
>>>>
>>>> return 0
>>>> }
>>> Dracut is used more in normal boot than kdump, if one enabled trace in
>>> grub and the events happen to be same, but we disabled it user will be
>>> not happy.
>> Yes, as long as they don't specify "rd.memdebug=4", the current implementation
>> isn't problematic.
>>
>> If people use "rd.memdebug=4", they should be aware what they are doing to trace,
>> also enabling the same events (module_load, module_put and alloc_pages) only is rare.
> Yes, they should be aware but still need some documentation..
OK, then I'd like to improve [PATCH v2 3/3] to add trace awareness.
Regards,
Xunlei
>> Regards,
>> Xunlei
>>
>>>> Regards,
>>>> Xunlei
>>>>
>>>>>> + tracekomem --cleanup
>>>>>> + fi
>>>>>> +}
>>>>>> +
>>>>>> # parameters: msg [trace_level:trace]...
>>>>>> make_trace_mem()
>>>>>> {
>>>>>> @@ -1296,6 +1304,9 @@ show_memstats()
>>>>>> iomem)
>>>>>> cat /proc/iomem
>>>>>> ;;
>>>>>> + komem)
>>>>>> + tracekomem
>>>>>> + ;;
>>>>>> esac
>>>>>> }
>>>>>>
>>>>>> diff --git a/modules.d/99base/init.sh b/modules.d/99base/init.sh
>>>>>> index a563393..e4f7cff 100755
>>>>>> --- a/modules.d/99base/init.sh
>>>>>> +++ b/modules.d/99base/init.sh
>>>>>> @@ -131,7 +131,7 @@ if ! getargbool 1 'rd.hostonly'; then
>>>>>> fi
>>>>>>
>>>>>> # run scriptlets to parse the command line
>>>>>> -make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab'
>>>>>> +make_trace_mem "hook cmdline" '1+:mem' '1+:iomem' '3+:slab' '4+:komem'
>>>>>> getarg 'rd.break=cmdline' -d 'rdbreak=cmdline' && emergency_shell -n cmdline "Break before cmdline"
>>>>>> source_hook cmdline
>>>>>>
>>>>>> @@ -160,7 +160,7 @@ fi
>>>>>>
>>>>>> udevproperty "hookdir=$hookdir"
>>>>>>
>>>>>> -make_trace_mem "hook pre-trigger" '1:shortmem' '2+:mem' '3+:slab'
>>>>>> +make_trace_mem "hook pre-trigger" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>>> getarg 'rd.break=pre-trigger' -d 'rdbreak=pre-trigger' && emergency_shell -n pre-trigger "Break before pre-trigger"
>>>>>> source_hook pre-trigger
>>>>>>
>>>>>> @@ -230,7 +230,7 @@ unset RDRETRY
>>>>>>
>>>>>> # pre-mount happens before we try to mount the root filesystem,
>>>>>> # and happens once.
>>>>>> -make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab'
>>>>>> +make_trace_mem "hook pre-mount" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>>> getarg 'rd.break=pre-mount' -d 'rdbreak=pre-mount' && emergency_shell -n pre-mount "Break pre-mount"
>>>>>> source_hook pre-mount
>>>>>>
>>>>>> @@ -266,11 +266,12 @@ done
>>>>>>
>>>>>> # pre pivot scripts are sourced just before we doing cleanup and switch over
>>>>>> # to the new root.
>>>>>> -make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab'
>>>>>> +make_trace_mem "hook pre-pivot" '1:shortmem' '2+:mem' '3+:slab' '4+:komem'
>>>>>> getarg 'rd.break=pre-pivot' -d 'rdbreak=pre-pivot' && emergency_shell -n pre-pivot "Break pre-pivot"
>>>>>> source_hook pre-pivot
>>>>>>
>>>>>> make_trace_mem "hook cleanup" '1:shortmem' '2+:mem' '3+:slab'
>>>>>> +cleanup_trace_mem
>>>>>> # pre pivot cleanup scripts are sourced just before we switch over to the new root.
>>>>>> getarg 'rd.break=cleanup' -d 'rdbreak=cleanup' && emergency_shell -n cleanup "Break cleanup"
>>>>>> source_hook cleanup
>>>>>> diff --git a/modules.d/99base/module-setup.sh b/modules.d/99base/module-setup.sh
>>>>>> index b03772e..a1569b1 100755
>>>>>> --- a/modules.d/99base/module-setup.sh
>>>>>> +++ b/modules.d/99base/module-setup.sh
>>>>>> @@ -35,6 +35,7 @@ install() {
>>>>>> inst_script "$moddir/initqueue.sh" "/sbin/initqueue"
>>>>>> inst_script "$moddir/loginit.sh" "/sbin/loginit"
>>>>>> inst_script "$moddir/rdsosreport.sh" "/sbin/rdsosreport"
>>>>>> + inst_script "$moddir/memtrace-ko.sh" "/sbin/tracekomem"
>>>>>>
>>>>>> [ -e "${initdir}/lib" ] || mkdir -m 0755 -p ${initdir}/lib
>>>>>> mkdir -m 0755 -p ${initdir}/lib/dracut
>>>>>> --
>>>>>> 1.8.3.1
>>>>>>
>>>>>> --
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>>>>> Thanks
>>>>> Dave
>>>>> --
>>>>> To unsubscribe from this list: send the line "unsubscribe initramfs" in
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>>> Thanks
>>> Dave
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe initramfs" in
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