RFR: 8224871: os::attempt_reserve_memory_at() tries too hard

[Per Liden]

Looks good.

/Per

On 5/28/19 3:07 PM, Erik Österlund wrote:
> Hi,
> 
> The os::attempt_reserve_memory_at() function on BSD, linux and Solaris 
> all try a bit too hard. They first try to mmap memory at a given 
> address. If that failed, rather than giving up as expected, it tries in 
> a loop to mmap random memory (without address hints), and looks if it so 
> happens to be that it can from these completely random and arbitrary 
> address ranges find overlapping ranges that happen to cross over the 
> exact range that was requested, and then cuts out the excess and returns 
> that. We really should just give up instead if the OS refused to hand 
> out memory at the requested address.
> 
> Bug:
> https://bugs.openjdk.java.net/browse/JDK-8224871
> 
> Webrev:
> http://cr.openjdk.java.net/~eosterlund/8224871/webrev.00/
> 
> Thanks,
> /Erik