Xueming Shen wrote:
http://cr.openjdk.java.net/~sherman/6929479/webrev/
This is a rfe to add a system property sun.zip.disableMmap to enable
the end user to disable the mmap usage in
Sun's java.util.zip.ZipFile implementaiton (for Solaris and Linux
platforms).
Application uses java.util.zip.ZipFile might experience SIGBUS vm
crash if the application mistakely over-writes
zip/jar files that are still being used, for example the application
server repeatedly deploy the same jar file into the
same location again and again while there is still code (running in
the same vm) still accessing this particular zip/
jar file (access the memory that mmapped the central directory of the
zip file). While this is indeed an programming
error in the offending application, there is situation that the end
user really does not have the control of those
applications and look for a workaround for the crash. With this
property set to true (-Dsun.zip.disableMmap=true)
the sun zipfile implementation reads in the central directory into the
memory instead of using mmap.
I've had to debug a few of these so this option should be very useful. I
wonder if sun.zip.disableMapping would be a slightly better name?
The changes looks reasonable to me - it's just a pity that we can't get
rid of USE_MMAP (the changes really make this stand out).
-Alan
