RFR 8226543 : Reduce GC pressure during message digest calculations in password-based encryption

Ivan Gerasimov ivan.gerasimov at oracle.com
Fri Jun 21 02:22:59 UTC 2019


In PBES1Core.deriveCipherKey() there are loops that look like following:

             for (int i = 0; i < iCount; i++) {
                 toBeHashed = md.digest(); // this resets the digest

Calling md.digest() each time allocates a new byte[] array.
It would be more GC friendly, if the same array were reused.

In the fix, a first call to md.digest() allocates a properly sized array.
Subsequent iterations reuse this array.

Would you please help review?

BUGURL: https://bugs.openjdk.java.net/browse/JDK-8226543
WEBREV: http://cr.openjdk.java.net/~igerasim/8226543/00/webrev/

No new regression test, as the behavior was not changed.
Mach5 control job is green (tiers 1-4 on all supported platforms).

With kind regards,
Ivan Gerasimov

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