RFR(S): 8020753: pthread_get_stacksize_np() workaround for OS X 10.9

[Igor Veresov]

I guess it's reasonable.

As for option (2) you can probably trigger the fix based on the kernel version, that is rather easy to get:

#include <errno.h>
#include <sys/sysctl.h>
char str[256];
size_t size = sizeof(str);
int ret = sysctlbyname("kern.osrelease", str, &size, NULL, 0);

Versions 13.x.x would be Mavericks. You can use it to put an additional assert.

igor




On Oct 23, 2013, at 7:20 AM, Gerard Ziemski <gerard.ziemski at oracle.com> wrote:

> Please review this proposed workaround for OS X 10.9 (Mavericks)
> 
> Description:
> 
> On Mac Os X 10.9 (Mavericks) the pthread_get_stacksize_np() API returns 128 pages for both main (primodial, primary) and secondary threads, when in fact 2048 pages are available for the main thread. pthread_get_stacksize_np() correctly returns 2048 pages for main thread on 10.6, 10.7 and 10.8 and probably all previous OS X versions.
> 
> An issue has been filed with Apple, but in the meantime we need to substitute 2048 pages whenever pthread_get_stacksize_np() returns anything else (ie. 128) on main thread.
> 
> The workaround uses hardcoded value of 2048 pages for main thread, because:
> 
> 1. The correct value can in fact be found at runtime using signals (please see my test case attached to the bug's JDK issue), however, such code needs signal handlers and also takes about 3.5 ms, so it's probably not a viable solution.
> 
> 2. We could also look-up OS X version at runtime to only use the workaround for 10.9, but that requires parsing an xml file, looking for a value that is internationalized, so it's non trivial (though might be doable assuming the time to execute is low enough)
> 
> 3. All JDK8 supported OS X versions (ie. 10.7, 10.8) return 2048.
> 
> In the future, this workaround might need to be revisited (ie. 2), but I believe that it's reasonable for now, though I would love to hear others opinions on this.
> 
> 
> Testing:
> 
> In progress...
> 
> 
> References:
> 
> http://cr.openjdk.java.net/~iklam/8020753/ziemski_rev1/
> https://bugs.openjdk.java.net/browse/JDK-8020753
> 
> 
> cheers
>