[Buildroot] [PATCH 2/2] fs/squashfs: Add option to compress with extreme options

[Linus Kaschulla via buildroot <buildroot@buildroot.org>]

mksquashfs allows to tweak many compressions parameters. Currently they
can't be changed from kmenu. Leaving out potential space savings.

This adds the option to enable a set of predetermined compression
options. This option is enabled by default for lz4 since lz4 currently
implicitly added the extreme to it in the makefile. So this aids in
keeping backward compatibility.

Signed-off-by: Linus Kaschulla <linus@cosmos-ink.net>
---
 fs/squashfs/Config.in   | 26 ++++++++++++++++++++++++++
 fs/squashfs/squashfs.mk |  6 +++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/fs/squashfs/Config.in b/fs/squashfs/Config.in
index 341e50a08c..41c782105d 100644
--- a/fs/squashfs/Config.in
+++ b/fs/squashfs/Config.in
@@ -89,4 +89,30 @@ config BR2_TARGET_ROOTFS_SQUASHFS4_ZSTD
 
 endchoice
 
+config BR2_TARGET_ROOTFS_SQUASHFS_EXTREME_COMP
+	bool "extreme compression if possible"
+	default BR2_TARGET_ROOTFS_SQUASHFS4_LZ4
+	help
+	  Use options to increase compression ration as much as
+	  possible, like using architecture-specific options, at
+	  the cost of time when assembling the filesystem image.
+
+	  For example:
+	   - with gzip and lzo, use -Xcompression-level 9
+	   - with xz use a architecture specific bjc (branch-call-jump) filter
+	   - with zstd use -Xcompression-level 22
+	   - and more
+
+config BR2_TARGET_ROOTFS_SQUASHFS_COMP_OPTS
+	string
+	depends on BR2_TARGET_ROOTFS_SQUASHFS_EXTREME_COMP
+	default "-Xcompression-level 9" if BR2_TARGET_ROOTFS_SQUASHFS4_GZIP
+	default "-Xcompression-level 9" if BR2_TARGET_ROOTFS_SQUASHFS4_LZO
+	default "-Xhc" if BR2_TARGET_ROOTFS_SQUASHFS4_LZ4
+	default "-Xbcj arm,armthumb" if BR2_TARGET_ROOTFS_SQUASHFS4_XZ && (BR2_arm || BR_aarch64)
+	default "-Xbcj powerpc" if BR2_TARGET_ROOTFS_SQUASHFS4_XZ && (BR2_powerpc || BR2_powerpc64)
+	default "-Xbcj sparc" if BR2_TARGET_ROOTFS_SQUASHFS4_XZ && (BR2_sparc || BR2_sparc64)
+	default "-Xbcj x86" if BR2_TARGET_ROOTFS_SQUASHFS4_XZ && (BR2_i386 || BR2_x86_64)
+	default "-Xcompression-level 22" if BR2_TARGET_ROOTFS_SQUASHFS4_ZSTD
+
 endif
diff --git a/fs/squashfs/squashfs.mk b/fs/squashfs/squashfs.mk
index 1790773f7e..51f8d0d7c9 100644
--- a/fs/squashfs/squashfs.mk
+++ b/fs/squashfs/squashfs.mk
@@ -25,7 +25,7 @@ ROOTFS_SQUASHFS_ARGS += -nopad
 endif
 
 ifeq ($(BR2_TARGET_ROOTFS_SQUASHFS4_LZ4),y)
-ROOTFS_SQUASHFS_ARGS += -comp lz4 -Xhc
+ROOTFS_SQUASHFS_ARGS += -comp lz4
 else ifeq ($(BR2_TARGET_ROOTFS_SQUASHFS4_LZO),y)
 ROOTFS_SQUASHFS_ARGS += -comp lzo
 else ifeq ($(BR2_TARGET_ROOTFS_SQUASHFS4_LZMA),y)
@@ -38,6 +38,10 @@ else
 ROOTFS_SQUASHFS_ARGS += -comp gzip
 endif
 
+ifeq ($(BR2_TARGET_ROOTFS_SQUASHFS_EXTREME_COMP),y)
+ROOTFS_SQUASHFS_ARGS += $(call qstrip,$(BR2_TARGET_ROOTFS_SQUASHFS_COMP_OPTS))
+endif
+
 define ROOTFS_SQUASHFS_CMD
 	$(HOST_DIR)/bin/mksquashfs $(TARGET_DIR) $@ $(ROOTFS_SQUASHFS_ARGS)
 endef
-- 
2.35.1

_______________________________________________
buildroot mailing list
buildroot@buildroot.org
https://lists.buildroot.org/mailman/listinfo/buildroot