On Thu, 4 Apr 2024 11:12:43 GMT, Severin Gehwolf <sgehw...@openjdk.org> wrote:
>> Please review this patch which adds a jlink mode to the JDK which doesn't >> need the packaged modules being present. A.k.a run-time image based jlink. >> Fundamentally this patch adds an option to use `jlink` even though your JDK >> install might not come with the packaged modules (directory `jmods`). This >> is particularly useful to further reduce the size of a jlinked runtime. >> After the removal of the concept of a JRE, a common distribution mechanism >> is still the full JDK with all modules and packaged modules. However, >> packaged modules can incur an additional size tax. For example in a >> container scenario it could be useful to have a base JDK container including >> all modules, but without also delivering the packaged modules. This comes at >> a size advantage of `~25%`. Such a base JDK container could then be used to >> `jlink` application specific runtimes, further reducing the size of the >> application runtime image (App + JDK runtime; as a single image *or* >> separate bundles, depending on the app being modularized). >> >> The basic design of this approach is to add a jlink plugin for tracking >> non-class and non-resource files of a JDK install. I.e. files which aren't >> present in the jimage (`lib/modules`). This enables producing a `JRTArchive` >> class which has all the info of what constitutes the final jlinked runtime. >> >> Basic usage example: >> >> $ diff -u <(./bin/java --list-modules --limit-modules java.se) >> <(../linux-x86_64-server-release/images/jdk/bin/java --list-modules >> --limit-modules java.se) >> $ diff -u <(./bin/java --list-modules --limit-modules jdk.jlink) >> <(../linux-x86_64-server-release/images/jdk/bin/java --list-modules >> --limit-modules jdk.jlink) >> $ ls ../linux-x86_64-server-release/images/jdk/jmods >> java.base.jmod java.net.http.jmod java.sql.rowset.jmod >> jdk.crypto.ec.jmod jdk.internal.opt.jmod >> jdk.jdi.jmod jdk.management.agent.jmod jdk.security.auth.jmod >> java.compiler.jmod java.prefs.jmod java.transaction.xa.jmod >> jdk.dynalink.jmod jdk.internal.vm.ci.jmod >> jdk.jdwp.agent.jmod jdk.management.jfr.jmod jdk.security.jgss.jmod >> java.datatransfer.jmod java.rmi.jmod java.xml.crypto.jmod >> jdk.editpad.jmod jdk.internal.vm.compiler.jmod >> jdk.jfr.jmod jdk.management.jmod jdk.unsupported.desktop.jmod >> java.desktop.jmod java.scripting.jmod java.xml.jmod >> jdk.hotspot.agent.jmod jdk.i... > > Severin Gehwolf has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains 100 commits: > > - Fix coment > - Fix comment > - Fix typo > - Revert some now unneded build changes > - Follow build tools naming convention > - Update to new build-time approach with delta in lib > - Make generation of fs_$module_files unconditional > - Merge branch 'master' into jdk-8311302-jmodless-link > - Fix copyright year > - Move CreateLinkableRuntimePlugin to build folder > > Keep runtime link supporting classes in package > jdk.tools.jlink.internal.runtimelink > - ... and 90 more: https://git.openjdk.org/jdk/compare/6ae1cf12...ce04f42a The new approach certainly makes the build part simpler, which I appreciate. Left some polishing comments. You don't need to address them until the general approach is accepted. make/CompileToolsJdk.gmk line 50: > 48: EXCLUDES := \ > 49: build/tools/classlist \ > 50: build/tools/runtimeimagelinkdeltaproducer \ This directory name is comically long. I guess that's not really a problem, but perhaps "linkdelta" would be descriptive enough given that the class has the full name anyway? make/Images.gmk line 114: > 112: ifeq ($(JLINK_PRODUCE_RUNTIME_LINK_JDK), true) > 113: RL_BUILD_CLASSES := runtimeimagelinkdeltaproducer-classes > 114: RL_DELTA_GEN_CLASSES := $(BUILDTOOLS_OUTPUTDIR)/$(RL_BUILD_CLASSES) With a shorter name, this could be just one line. make/Images.gmk line 119: > 117: RL_DIFFS_OUTPUT_FILE_ARG := > $(JDK_IMAGE_DIR)/lib/runtime-image-link.delta > 118: RL_MOD_PATH_ARG := $(IMAGES_OUTPUTDIR)/jmods > 119: TOOL_RUNTIME_IMAGE_LINK_DELTA_PRODUCER := $(BUILD_JAVA) --add-modules > jdk.jlink \ All of these are only used once so should rather be inlined. I think that makes it easier to understand and read. make/Images.gmk line 122: > 120: > --add-exports=jdk.jlink/jdk.tools.jlink.internal.runtimelink=ALL-UNNAMED \ > 121: --add-exports=java.base/jdk.internal.module=ALL-UNNAMED \ > 122: --add-exports=java.base/jdk.internal.jimage=ALL-UNNAMED \ These three are repeated in both compilation and runtime so could potentially be set in a variable to avoid the duplication. make/Images.gmk line 208: > 206: WARN := Creating CDS$$($1_$2_DUMP_TYPE) archive for jdk image for > $1, \ > 207: INFO := Using CDS flags for $1: $$($1_$2_CDS_DUMP_FLAGS), \ > 208: DEPS := $$(FINAL_JDK_JLINK), \ Does this actually interfere with the cds archive creation? I would assume they output to different files and they aren't even running `java` from the same image. If not, I would skip the whole `FINAL_JDK_JLINK` and just add `$(diff_runtime_jdk)` to `JDK_TARGETS`. ------------- PR Review: https://git.openjdk.org/jdk/pull/14787#pullrequestreview-1979812209 PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1551631105 PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1551639403 PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1551648048 PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1551652030 PR Review Comment: https://git.openjdk.org/jdk/pull/14787#discussion_r1551636954
