RFR(S): 8186286: [BSD] Primary thread's stack size is reported incorrectly
david.holmes at oracle.com
Thu Aug 17 21:54:51 UTC 2017
On 18/08/2017 1:01 AM, Haug, Gunter wrote:
> Thanks for the review, Aleksey and Thomas
> You’re right, it is much nicer to use the macros. I’ve updated the change accordingly:
I'm unclear about the logic change here. If you round down then there is
a chance you will enter the following if-block where otherwise you would
915 *size = align_down(*size, getpagesize());
917 if ((*size) < (DEFAULT_MAIN_THREAD_STACK_PAGES *
Have you verified with a range of aligned and unaligned stack sizes
around that threshhold that everything works okay?
Some typos in the comment block:
alligned -> aligned
boundries -> boundaries
I round -> We round
> @Thomas: os::vm_page_size() is not used in current_stack_region(), I think because of initialization dependencies.
I don't see the dependency. It requires that it only be used after
os::init() has been called. AFAICS the first time we will use this logic
is when we attach the main thread, which happens after os::init().
> Best regards,
> From: Thomas Stüfe <thomas.stuefe at gmail.com>
> Date: Thursday, 17. August 2017 at 15:06
> To: "Haug, Gunter" <gunter.haug at sap.com>
> Cc: "hotspot-dev at openjdk.java.net" <hotspot-dev at openjdk.java.net>
> Subject: Re: RFR(S): 8186286: [BSD] Primary thread's stack size is reported incorrectly
> Hi Gunter,
> On Thu, Aug 17, 2017 at 2:24 PM, Haug, Gunter <gunter.haug at sap.com<mailto:gunter.haug at sap.com>> wrote:
> can I please have reviews and a sponsor fort the following small bug fix:
> At least on Mac OS 10.12 we have observed stack sizes of the primary thread not aligned to pages boundries. This can be provoked by e.g. setrlimit() (ulimit -s xxxx in the shell).This voids the computation of the addresses of the guard pages.
> Apparently Mac OS actually rounds upwards to next multiple of page size however, it is conservative to round downwards here to be on the safe side.
> Thanks and best regards,
> Thanks for the patch!
> Very minor nits: what Alexey wrote (we also have "is_aligned"). Plus, any reason not to use os::vm_page_size()? Initialization dependencies?
> Kind Regards, Thomas
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