RFR: 6478546: FileInputStream.read() throws OutOfMemoryError when there is plenty available [v7]

[Daniel Fuchs]

On Wed, 20 Jul 2022 23:41:04 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

>> Modify native multi-byte read-write code used by the `java.io` classes to limit the size of the allocated native buffer thereby decreasing off-heap memory footprint and increasing throughput.
>
> Brian Burkhalter has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 12 additional commits since the last revision:
> 
>  - 6478546: Miscellaneous cleanup
>  - Merge
>  - Merge
>  - 6478546: Use dynamically sized temporary direct buffers
>  - Merge
>  - Merge
>  - 6478546: Add break in write loop on ExceptionOccurred
>  - Merge
>  - 6478546: Clean up io_util.c
>  - Merge
>  - ... and 2 more: https://git.openjdk.org/jdk/compare/a3b1a325...9a138636

src/java.base/share/classes/java/io/RandomAccessFile.java line 112:

> 110:         }
> 111: 
> 112:         int multiple = (len + MIN_BUFFER_SIZE - 1)/MIN_BUFFER_SIZE;

isn't that equivalent `(len / MIN_BUFFER_SIZE) + 1`, given that len cannot be 0 or a multiple of MIN_BUFFER_SIZE?

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PR: https://git.openjdk.org/jdk/pull/8235