On 03/29/2017 at 03:10 PM, Dave Young wrote:
Hi Xunlei,
On 03/29/17 at 02:38pm, Xunlei Pang wrote:
> We replace "reserved_memory= 8192" with "reserved_memory = 1024"
> in /etc/lvm/lvm.conf used by "lvm2", this can save 7MB peak memory
> consumption, so we lower the possibility of kdump OOM.
>
> 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 agree that we can use 1MB under kdump as long as there
> are not so many lvm targets invloved.
>
> We modify /etc/lvm/lvm.conf when "99kdumpbase" install() is executed,
> because it is parsed after "90lvm" by dracut.
>
> Signed-off-by: Xunlei Pang <xlpang(a)redhat.com>
> ---
> dracut-module-setup.sh | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh
> index 1f96bb8..674f3ee 100755
> --- a/dracut-module-setup.sh
> +++ b/dracut-module-setup.sh
> @@ -743,4 +743,9 @@ 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 = 8192" with "reserved_memory = 1024" to
lower memory pressure
The code is setting reserved_memory = 1024 unconditionally, not only for
relacing 8192 with 1024, need update the commit to match the code. Also
the line is too long as well.
It only does replacing actually, but if lvm.conf doesn't exist, the code actually does
nothing.
> + sed -i -e
's/\(^[[:space:]]*\)reserved_memory[[:space:]]*=[[:space:]]*[[:digit:]]*/ \
> + \1reserved_memory = 1024/' ${initdir}/etc/lvm/lvm.conf
&>/dev/null
Nitpick, this can be changed to 80 columns alignment, like move sed -i
-e in a seperate line.
ok, but it's a little hard for shell, we have many code very long including dracut,
what about the following, I make each independent part one line?
sed -i -e \
's/\(^[[:space:]]*\)reserved_memory[[:space:]]*=[[:space:]]*[[:digit:]]*/\1reserved_memory
= 1024/' \
${initdir}/etc/lvm/lvm.conf &>/dev/null
Regards,
Xunlei
> }
> --
> 1.8.3.1
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Thanks
Dave