RFR[9u-dev]: 8146683: check_addr0 should be more efficient

Cheleswer Sahu cheleswer.sahu at oracle.com
Tue Feb 23 08:38:31 UTC 2016



Please review the code changes for https://bugs.openjdk.java.net/browse/JDK-8146683 .


Webrev link: http://cr.openjdk.java.net/~csahu/8146683/

JBS Link: https://bugs.openjdk.java.net/browse/JDK-8146683


Bug Brief: 

While investigating  bug https://bugs.openjdk.java.net/browse/JDK-8144483  it has been observed that "check_addr0() " function  is not written efficiently.

This function is trying to read each "prmap_t" entry in "/proc/self/map" file one by one which is time taking and can cause in long pauses.


Solution proposed:

Instead of reading each "prmap_t" entry in "/proc/self/map" file one by one, read the entries in chunks. There can be many entries in "map" file, so I have decided to read these

in chunks of 100  "prmap_t" entries. Reading entries in chunks saves a lot of read calls and results in smaller pause times. 





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