On Wednesday 29 March 2017 02:01 PM, Dave Young wrote:
On 03/29/17 at 04:16pm, Xunlei Pang wrote:
> We replace "reserved_memory = XXXX"(default value is 8192) with
> "reserved_memory = 1024" in /etc/lvm/lvm.conf used by "lvm2", it
> can save 7MB peak memory consumption, so lower the possibility of
> OOM under kdump.
>
> For kdump, we don't have too many lvm targets, lvm2 locates in the
> RAM(rootfs), so don't need that much memory, as discussed with lvm
> people, they agreed that we use 1MB under kdump as long as there
> are not that many lvm targets invloved.
>
> We modify /etc/lvm/lvm.conf when "99kdumpbase" install() is executed,
> because it is parsed after "90lvm" by dracut.
>
> We add the code unconditionally with &>/dev/null to ignore errors, it
> doesn't matter in case of "lvm" not included(i.e. there is no
lvm.conf).
>
> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com>
Acked-by: Pratyush Anand <panand(a)redhat.com>
>> ---
>> dracut-module-setup.sh | 9 +++++++++
>> 1 file changed, 9 insertions(+)
>>
>> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
>> index 1f96bb8..5b2c942 100755
>> --- a/dracut-module-setup.sh
>> +++ b/dracut-module-setup.sh
>> @@ -743,4 +743,13 @@ install() {
>> # target. Ideally all this should be pushed into dracut iscsi module
>> # at some point of time.
>> kdump_check_iscsi_targets
>> +
>> + # For the lvm type target under kdump, in /etc/lvm/lvm.conf we can
>> + # safely replace "reserved_memory=XXXX"(default value is 8192)
with
>> + # "reserved_memory=1024" to lower memory pressure under kdump. We
do
>> + # it unconditionally here, if "/etc/lvm/lvm.conf" doesn't
exist, it
>> + # actually does nothing.
>> + sed -i -e \
>> +
's/\(^[[:space:]]*reserved_memory[[:space:]]*=\)[[:space:]]*[[:digit:]]*/\1 1024/'
\
>> + ${initdir}/etc/lvm/lvm.conf &>/dev/null
>> }
>
> Thanks for the update, it looks better.
>
> Acked-by: Dave Young <dyoung(a)redhat.com>
>
> Thanks
> Dave
>
>> --
>> 1.8.3.1
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