RFR: 8324781: runtime/Thread/TestAlwaysPreTouchStacks.java failed with Expected a higher ratio between stack committed and reserved [v3]

[Johan Sjölen]

On Mon, 8 Apr 2024 09:07:26 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Liming Liu has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Disable UseMadvPopulateWrite when not supported
>
> src/hotspot/os/linux/os_linux.cpp line 387:
> 
>> 385:     } else {
>> 386:       ++walker;
>> 387:     }
> 
> I can't tell if this code is correct or not.
> * When is walker ever nullptr?
> * Don't wee need error handling for strtol?
> 
> Maybe this is all pre-existing issues, but I'd like to get someone else to review and sign off on this code.

Not typical code for me either.

Quoting my man pages:


     If endptr is  not NULL, strtol() stores the address  of the first
     invalid character  in *endptr.  If  there were no digits  at all,
     strtol()  stores  the original  value  of  nptr in  *endptr  (and
     returns  0).  In  particular, if  *nptr is  not [aq]\0[aq]  but
     **endptr is [aq]\0[aq] on return, the entire string is valid.


Given a string such as `2.6.5`, each `strtol` will put `walker` at a new `.` and as minor is always set the condition in the loop will become false. The `walker` will never be null. Looking at the documentation, we don't need error-handling for the `strtol` call (won't over/underflow and will be a valid version revision).

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PR Review Comment: https://git.openjdk.org/jdk/pull/18592#discussion_r1555770161