Integrated: 8275426: PretouchTask num_chunks calculation can overflow

[Kim Barrett]

On Mon, 18 Oct 2021 17:43:58 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change to part of the calculation of the number of
> threads to apply to a PretouchTask when using a gang of worker threads.
> 
> The previous calculation of the number of chunks in the range to be touched
> can overflow in the numerator.  (This may only be a realistic problem on
> 32bit platforms.  On 64bit platforms the value constraint on the chunk size
> and plausible or architectural limits on the size of the range probably
> prevent such overflow from occurring.)
> 
> Testing:
> mach5 tier1
> Locally (linux-x64) ran with logging of the pretouch parameters enabled,
> with various chunk sizes configured, and hand-checked the logged values.

This pull request has now been integrated.

Changeset: 60cb27dc
Author:    Kim Barrett <kbarrett at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/60cb27dcda475a66e329359ac1ee3ffcde95c657
Stats:     1 line in 1 file changed: 0 ins; 0 del; 1 mod

8275426: PretouchTask num_chunks calculation can overflow

Reviewed-by: ayang, tschatzl

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PR: https://git.openjdk.java.net/jdk/pull/5993