RFR(S) 8241004: NMT tests fail on unalinged thread size with debug build

[Thomas Stüfe]

Hi Boris,

I think this looks good. Zhengyu should look at this to make sure.

When looking at os::committed_in_range() I remembered that this was a
rather specific function. Its name suggests that it counts all committed
pages in a range; but it only counts the first committed contiguous range,
then stops.

Thanks, Thomas



On Wed, May 13, 2020 at 6:29 PM Boris Ulasevich <boris.ulasevich at bell-sw.com>
wrote:

> Hi Thomas,
>
> Good point! Thanks.
> I reworked the function to ease both restrictions.
> http://cr.openjdk.java.net/~bulasevich/8241004/webrev.01
>
> regards,
> Boris
>
> On 13.05.2020 08:59, Thomas Stüfe wrote:
>
> Hi Boris,
>
> Note that we have unaligned stack boundaries on AIX too, not so strange :)
>
> What I do not like about the solution is that it loosens the restriction
> on the input size while keeping the restriction on the start address. I'd
> rather see this function either in its current form (requiring the input
> ranges to be page aligned) or the input range to be completely
> unrestricted. This function is currently only used by NMT but it is useful
> and may be used in other places too.
>
> Can you make it work with arbitrary input ranges? I do not think this
> would require much changes from your patch, you do most of the work already.
>
> Thanks!
>
> ..Thomas
>
>
>
> On Thu, May 7, 2020 at 2:56 PM boris <boris.ulasevich at bell-sw.com> wrote:
>
>> Hi,
>>
>> Please review the following change.
>>
>> http://cr.openjdk.java.net/~bulasevich/8241004/webrev.00
>> http://bugs.openjdk.java.net/browse/JDK-8241004
>>
>> The stack size created by the implementation of the pthread library is
>> not necessarily page aligned. It is weird, but it is not forbidden: the
>> pthread library may add some gap on it own. My change removes stack size
>> alignment assert checks and tunes NMT committed range calculation for
>> the case of unaligned stack size.
>>
>> thanks,
>> Boris
>>
>
>