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![Bertrand Jacquin](/assets/img/avatar_default.png)
Since module-init-tools (gzip) and kmod (gzip and xz) support compressed modules, it could be useful to include a support for compressing modules right after having them installed. Doing this in kbuild instead of per distro can permit to make this kind of usage more generic. This patch add a Kconfig entry to "Enable loadable module support" menu and let you choose to compress using gzip (default) or xz. Both gzip and xz does not used any extra -[1-9] option since Andi Kleen and Rusty Russell prove no gain is made using them. gzip is called with -n argument to avoid storing original filename inside compressed file, that way we can save some more bytes. On a v3.16 kernel, 'make allmodconfig' generated 4680 modules for a total of 378MB (no strip, no sign, no compress), the following table shows observed disk space gain based on the allmodconfig .config : | time | +-------------+-----------------+ | manual .ko | make | size | percent | compression | modules_install | | gain +-------------+-----------------+------+-------- - | | 18.61s | 378M | GZIP | 3m16s | 3m37s | 102M | 73.41% XZ | 5m22s | 5m39s | 77M | 79.83% The gain for restricted environnement seems to be interesting while uncompress can be time consuming but happens only while loading a module, that is generally done only once. This is fully compatible with signed modules while the signed module is compressed. module-init-tools or kmod handles decompression and provide to other layer the uncompressed but signed payload. Reviewed-by: Willy Tarreau <w@1wt.eu> Signed-off-by: Bertrand Jacquin <beber@meleeweb.net> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
41 lines
1.2 KiB
Makefile
41 lines
1.2 KiB
Makefile
# ==========================================================================
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# Installing modules
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# ==========================================================================
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PHONY := __modinst
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__modinst:
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include scripts/Kbuild.include
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#
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__modules := $(sort $(shell grep -h '\.ko$$' /dev/null $(wildcard $(MODVERDIR)/*.mod)))
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modules := $(patsubst %.o,%.ko,$(wildcard $(__modules:.ko=.o)))
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PHONY += $(modules)
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__modinst: $(modules)
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@:
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# Don't stop modules_install if we can't sign external modules.
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quiet_cmd_modules_install = INSTALL $@
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cmd_modules_install = \
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mkdir -p $(2) ; \
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cp $@ $(2) ; \
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$(mod_strip_cmd) $(2)/$(notdir $@) ; \
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$(mod_sign_cmd) $(2)/$(notdir $@) $(patsubst %,|| true,$(KBUILD_EXTMOD)) ; \
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$(mod_compress_cmd) $(2)/$(notdir $@)
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# Modules built outside the kernel source tree go into extra by default
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INSTALL_MOD_DIR ?= extra
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ext-mod-dir = $(INSTALL_MOD_DIR)$(subst $(patsubst %/,%,$(KBUILD_EXTMOD)),,$(@D))
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modinst_dir = $(if $(KBUILD_EXTMOD),$(ext-mod-dir),kernel/$(@D))
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$(modules):
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$(call cmd,modules_install,$(MODLIB)/$(modinst_dir))
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# Declare the contents of the .PHONY variable as phony. We keep that
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# information in a variable so we can use it in if_changed and friends.
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.PHONY: $(PHONY)
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