On Wed, 22 May 2024 13:23:25 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 110 commits: > > - Merge branch 'master' into jdk-8311302-jmodless-link > - Fix new line in jlink.properties > - Merge branch 'master' into jdk-8311302-jmodless-link > - Simplify JLINK_JDK_EXTRA_OPTS var handling > - Only add runtime track files for linkable runtimes > - Generate the runtime image link diff at jlink time > > But only do that once the plugin-pipeline has run. The generation is > enabled with the hidden option '--generate-linkable-runtime' and > the resource pools available at jlink time are being used to generate > the diff. > - Merge branch 'master' into jdk-8311302-jmodless-link > - Use shorter name for the build tool > - Review feedback from Erik J. > - Remove dependency on CDS which isn't needed anymore > - ... and 100 more: https://git.openjdk.org/jdk/compare/4f1a10f8...e1e3f02f I've been looking through the changes. One thing that I'm wondering about is whether --generate-runtime-link-image should disable the keeping of packaged modules (set JLINK_KEEP_PACKAGED_MODULES to false). It seems surprising to use this configure option and have the jlink command in the build also copy the packaged modules into the image. (Doing that would of course mean that several existing jlink tests would need some changes, either to `@requires` or to remove the checks for the `jmods` directory) ------------- PR Comment: https://git.openjdk.org/jdk/pull/14787#issuecomment-2143963280
