On Fri, 27 Oct 2023 12:28:51 GMT, Thomas Stuefe <stu...@openjdk.org> wrote:
>> Analysts and supporters often use /proc/xx/maps to make sense of the memory >> footprint of a process. >> >> Interpreting the memory map correctly can help when used as a complement to >> other tools (e.g. NMT). There even exist tools out there that attempt to >> annotate the process memory map with JVM information. >> >> That, however, can be more accurately done from within the JVM, at least for >> mappings originating from hotspot. After all, we can correlate the mapping >> information in NMT with the VMA map. >> >> Example output (from a spring petstore run): >> >> [example_system_map.txt](https://github.com/openjdk/jdk/files/13179054/example_system_map.txt) >> >> This patch adds the VM annotations for VMAs that are *mmaped*. I also have >> an experimental patch that works with malloc'ed memory, but it is not ready >> yet for consumption and I leave that part of for now. > > Thomas Stuefe has updated the pull request incrementally with three > additional commits since the last revision: > > - Fix spelling > - timeout fuse > - Feedback Johan I really like this feature, hope the other platforms can be done as well. (I am also really looking forward to seeing how you did the "malloc" version) I think we should set the user expectations correctly and say somewhere that these mappings are only for mmaped memory, ex change: `Memory mappings:` to `Memory mappings (mmaped):` or something like that. These lines look akward next to each other: 0x000000070a400000 - 0x0000000800000000 4123000832 ---p 00000000 JAVAHEAP 0x00007f4e747dd000 - 0x00007f4e747e1000 16384 ---p 00000000 STACK(72821 "AWT-EventQueue-0") 0x0000563e6decb000 - 0x0000563e6decc000 4096 r--p 00000000 /home/gerard/Desktop/Work/8318636/jdk/build/linux-x86_64-server-fastdebug/images/jdk/bin/java 0x00007f4e26000000 - 0x00007f4e26d3b000 13873152 rw-p 00001000 CDS /home/gerard/Desktop/Work/8318636/jdk/build/linux-x86_64-server-fastdebug/images/jdk/lib/server/classes.jsa in my opinion. The majority of entries either have the component or path in the **info** field (except CDS). Could we print it simply as: 0x000000070a400000 - 0x0000000800000000 4123000832 ---p 00000000 JAVAHEAP 0x00007f4e747dd000 - 0x00007f4e747e1000 16384 ---p 00000000 STACK(72821 "AWT-EventQueue-0") 0x0000563e6decb000 - 0x0000563e6decc000 4096 r--p 00000000 /home/gerard/Desktop/Work/8318636/jdk/build/linux-x86_64-server-fastdebug/images/jdk/bin/java 0x00007f4e26000000 - 0x00007f4e26d3b000 13873152 rw-p 00001000 CDS=/home/gerard/Desktop/Work/8318636/jdk/build/linux-x86_64-server-fastdebug/images/jdk/lib/server/classes.jsa I find the compact way more aesthetically pleasing and easier to read. Next I'm going to start looking into the implementation... ------------- Changes requested by gziemski (Committer). PR Review: https://git.openjdk.org/jdk/pull/16301#pullrequestreview-1702252387
