Re: [PATCH] kdumpctl: eliminate redundant lsinitrd in dracut

[Ziyue Yang]

Hi Dave,

The lsinitrd call is subject to the variable maxloglvl, and maxloglvl is
generated by:

for lvl in $stdloglvl $sysloglvl $fileloglvl $kmsgloglvl;
    do(( $lvl > $maxloglvl_l )) && maxloglvl_l=$lvl
done
readonly maxloglvl=$maxloglvl_l
export maxloglvl

so -L option(controlling stdloglvl) won't work.

BTW sysloglvl=2 works. I'll make a new patch for that.

On Tue, May 9, 2017 at 1:00 PM, Dave Young <dyoung(a)redhat.com&gt; wrote:

>  Hi Ziyue,
>
>  On 05/09/17 at 10:01am, Ziyue Yang wrote:
>  > Currently in Fedora/RedHat dracut installs its fedora.conf.example
>  > as the default config file, in which sysloglvl is set 5. This leads
>  > to maxloglvl=5 in dracut calls, making unnecessary lsinitrd calls
>  > during initramfs builds.
>  >
>  > This patch makes use of --conf and --confdir arguments of dracut,
>  > creates temp config directory before mkdumprd(dracut) calls. It
>  > appends sysloglvl=0 option by creating a 99-kdumpctl.conf file in
>  > the temp config directory.
>  >
>  > 1) Before this patch
>  > $ kdumpctl stop; touch /etc/kdump.conf; time kdumpctl start
>  > kexec: unloaded kdump kernel
>  > Stopping kdump: [OK]
>  > Detected change(s) in the following file(s):
>  >   /etc/kdump.conf
>  > Rebuilding /boot/initramfs-4.10.10-200.fc25.x86_64kdump.img
>  4.10.10-200.fc25_x86_64
>  > kexec: loaded kdump kernel
>  > Starting kdump: [OK]
>  > real    0m18.716s
>  > user    0m13.863s
>  > sys     0m3.269s
>  >
>  > 2) After this patch
>  > $ kdumpctl stop; touch /etc/kdump.conf; time kdumpctl start
>  > kexec: unloaded kdump kernel
>  > Stopping kdump: [OK]
>  > Detected change(s) in the following file(s):
>  >   /etc/kdump.conf
>  > Rebuilding /boot/initramfs-4.10.10-200.fc25.x86_64kdump.img
>  4.10.10-200.fc25_x86_64
>  > kexec: loaded kdump kernel
>  > Starting kdump: [OK]
>  > real    0m13.665s
>  > user    0m10.945s
>  > sys     0m2.907s
>  >
>  > Signed-off-by: Ziyue Yang <ziyang(a)redhat.com&gt;
>  > ---
>  >  kdumpctl | 16 +++++++++++++++-
>  >  1 file changed, 15 insertions(+), 1 deletion(-)
>  >
>  > diff --git a/kdumpctl b/kdumpctl
>  > index 4d6b3e8..0612294 100755
>  > --- a/kdumpctl
>  > +++ b/kdumpctl
>  > @@ -5,7 +5,6 @@ KDUMP_KERNELVER=""
>  >  KDUMP_COMMANDLINE=""
>  >  KEXEC_ARGS=""
>  >  KDUMP_CONFIG_FILE="/etc/kdump.conf"
>  > -MKDUMPRD="/sbin/mkdumprd -f"
>  >  SAVE_PATH=/var/crash
>  >  SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
>  >  INITRD_CHECKSUM_LOCATION="/boot/.fadump_initrd_checksum"
>  > @@ -20,6 +19,18 @@ DEFAULT_DUMP_MODE="kdump"
>  >  image_time=0
>  >
>  >  [[ $dracutbasedir ]] || dracutbasedir=/usr/lib/dracut
>  > +
>  > +# lower dracut's default sysloglvl to speedup initramfs build
>  > +DRACUT_SYSLOGLVL="0"
>  > +# make temp dir for dracut conf files
>  > +[[ $dracutconfdir ]] || dracutconfdir=/tmp/kdumpctl.dracut.conf
>  > +mkdir -p $dracutconfdir/dracut.conf.d
>  > +[[ -e $dracutbasedir/dracut.conf.d ]] && cp -rf
>  $dracutbasedir/dracut.conf.d $dracutconfdir/
>  > +[[ -e $dracutbasedir/dracut.conf ]] && cp -rf
>  $dracutbasedir/dracut.conf $dracutconfdir/
>  > +echo "sysloglvl=$DRACUT_SYSLOGLVL" > $dracutconfdir/dracut.conf.d/
>  99-kdumpctl.conf
>  > +
>  > +MKDUMPRD="/sbin/mkdumprd --conf $dracutconfdir/dracut.conf --confdir
>  $dracutconfdir/dracut.conf.d -f"
>  > +
>
>  Looking at dracut manpage, there is an option --stdlog or -L,
>         -L, --stdlog <level>
>             [0-6] Specify logging level (to standard error)
>
>                       0 - suppress any messages
>                       1 - only fatal errors
>                       2 - all errors
>                       3 - warnings
>                       4 - info
>                       5 - debug info (here starts lots of output)
>                       6 - trace info (and even more)
>
>  Can you try if this option works instead of copying the dracut config
>  files?
>
>  OTOH, use '0' seems mute all messages, but it is worth to try 2 and 1,
>  see if it also works, if 2 works then it would be better.
>
>  >  . $dracutbasedir/dracut-functions.sh
>  >  . /lib/kdump/kdump-lib.sh
>  >
>  > @@ -284,6 +295,9 @@ rebuild_initrd()
>  >               rebuild_kdump_initrd
>  >       fi
>  >
>  > +     # delete tmp conf folder for dracut
>  > +     rm -rf /tmp/kdumpctl.dracut.conf
>  > +
>  >       return $?
>  >  }
>  >
>  > --
>  > 2.9.3
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>
>  Thanks
>  Dave
>