RFR: 8368781: PerfMemory - make issues more transparent [v7]

[Goetz Lindenmaier]

On Tue, 21 Oct 2025 14:35:28 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> Currently issues with perfMemory like problems with the secure tmp subdirectory creation are not very transparent in release JVMs.
>> 
>> There exists some warnings traces but they are behind develop flags like Verbose so only available in debug JVMs.
>> We could (in case of issues) store some information and write it later into hsinfo/hserr files ; or make the existing warnings available too in release JVMs.
>
> Matthias Baesken has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Reformatting suggested by David
>  - unneeded \ removed

A general remark:
A few messages start with a capital letter.  Personally, I prefer proper sentences or text close to that, but I think it is more common in the code base to not capitalize single phrases. Maybe we can harmonize this here, as we touch the messages anyways.

Also, I think the JBS issue should be Enhancement, and I would appreciate a sentence in the description of how to retrieve the messages after the change.

src/hotspot/os/posix/perfMemory_posix.cpp line 1042:

> 1040: 
> 1041:   if (mapAddress == MAP_FAILED) {
> 1042:     log_debug(perf)("mmap failed -  %s", os::strerror(errno));

You might fix the double whitespace here ... or is this intended?

src/hotspot/os/windows/perfMemory_windows.cpp line 99:

> 97:   if (fd == OS_ERR) {
> 98:     log_debug(perf)("Could not create Perfdata save file: %s: %s",
> 99:                     destfile, os::strerror(errno));

Should we spell Perfdata camel-case as above?

src/hotspot/os/windows/perfMemory_windows.cpp line 105:

> 103:       int nbytes = ::_write(fd, addr, (unsigned int)remaining);
> 104:       if (nbytes == OS_ERR) {
> 105:         log_debug(perf)("Could not write Perfdata save file: %s: %s",

Camel-case?

src/hotspot/os/windows/perfMemory_windows.cpp line 246:

> 244:     //
> 245:     log_debug(perf)("%s is not a directory, file attributes = "
> 246:                     INTPTR_FORMAT, path, fa);

Maybe use : instead of = for consistency

src/hotspot/os/windows/perfMemory_windows.cpp line 1176:

> 1174:       if (!SetFileSecurity(dirname, secInfo, pDirSA->lpSecurityDescriptor)) {
> 1175:         lasterror = GetLastError();
> 1176:         log_debug(perf)("SetFileSecurity failed for %s directory. lasterror %d", dirname, lasterror);

Maybe add = after lasterror.

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PR Review: https://git.openjdk.org/jdk/pull/27602#pullrequestreview-3364026379
PR Review Comment: https://git.openjdk.org/jdk/pull/27602#discussion_r2450685542
PR Review Comment: https://git.openjdk.org/jdk/pull/27602#discussion_r2450724408
PR Review Comment: https://git.openjdk.org/jdk/pull/27602#discussion_r2450724966
PR Review Comment: https://git.openjdk.org/jdk/pull/27602#discussion_r2450730281
PR Review Comment: https://git.openjdk.org/jdk/pull/27602#discussion_r2450736621