RFR: 8319873: Add windows implementation for jcmd System.map and System.dump_map [v10]

[Simon Tooke]

On Wed, 11 Sep 2024 14:57:08 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

>> Simon Tooke has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   changes per review
>
> Hi,
> Great to bring up a Windows version of this.
> 
> Is the offset column useful?
> It tells us whether a line is the start of an allocation (offset 0) or a continuation of one.  Maybe that is useful if there is no name from NMT?  I didn't yet notice one where it helped but maybe...
> 
> If it really is a useful column, is it possible to tweak the columns so the "JAVAHEAP" stays in line?
> 
> 0x0000000706000000-0x0000000715a00000    262144000 rw--  c-pvt         0 JAVAHEAP 
> 0x0000000715a00000-0x00000007ffe00000   3930062848 ----  r-pvt 0xfa00000 JAVAHEAP 
> 0x00000007ffe00000-0x0000000800000000      2097152 rw--  c-pvt 0xf9e00000 JAVAHEAP 
> 
> Maybe the offset column is just too narrow, and the INDENT_BY(72) needs to be bigger, plus adjusting the header string?  Java heap seems to be the value that is likely to be largest here, so allowing more space would be good.
> 
> 
> On Linux I see info and file have separate columns.  Here, "vm info/file" is the column?
> Mostly I see there being either some info or a file, although CDS and classes.jsa is a line that has both. I like what you have here where it will print "CDS /path/classes.jsa" withouth using two columns. 8-)
> If it were just called "info/file" then I couldn't think there was a "vm" column that had failed to print.

Hello @kevinjwalls , and thank you for your review!  I have attempted to address your concerns with my use of 'fatal()' by replacing with a message in the returned output and an assert().

I have also adjusted the spacing of the offset field in the output, but kept it for parity with the Linux version.

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PR Comment: https://git.openjdk.org/jdk/pull/20597#issuecomment-2346625795