Re: [PATCH 1/2] fadump: do not use squash to reduce image size
Hi Hari,
On Fri, 21 Oct 2022 12:17:28 +0530
Hari Bathini <hbathini(a)linux.ibm.com> wrote:
With commit fa9201b2 ("fadump: isolate fadump initramfs image
within
the default one"), initramfs image gets to hold two squash images, one
for production kernel boot purpose and the other for capture kernel
boot. Having separate images improved reliability for both production
kernel and capture kernel boot scenarios, but the size of initramfs
image became considerably larger.
Instead of having squash images, compressing $initdir without using
squash images reduced the size of initramfs image for fadump case by
around 30%. So, avoid using squash for fadump case.
Signed-off-by: Hari Bathini <hbathini(a)linux.ibm.com>
---
kdump-lib.sh | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kdump-lib.sh b/kdump-lib.sh
index 817652d..543b5d1 100755
--- a/kdump-lib.sh
+++ b/kdump-lib.sh
@@ -23,6 +23,13 @@ is_fadump_capable()
is_squash_available()
{
+ # Don't use squash with fadump as it creates two squash images within the
+ # same initramfs image, which negatively impacts compression ratio &
+ # increases the size of the initramfs image.
+ if is_fadump_capable; then
+ return 1
+ fi
+
I absolutely don't like this patch. You are basically turning all
is_squash_available calls to noops for fadump. Including the ones in
mkfadumprd from witch one reads
if is_squash_available; then
_dracut_isolate_args+=(--add squash)
fi
So instead of simply removing the if-statement you turn it into dead
code.
I suggest you remove the code above and add the --omit squash option to
the mkdumprd call in mkfadumprd. That should give exactly what you want
without the need to add an other special handling for fadump.
Thanks
Philipp
for kmodule in squashfs overlay loop; do
if [[ -z $KDUMP_KERNELVER ]]; then
modprobe --dry-run $kmodule &> /dev/null || return 1