On Thu, 22 Nov 2007 13:14:47 +0900 "Trustin Lee" <[EMAIL PROTECTED]> wrote:
> On Nov 21, 2007 7:25 PM, Mladen Turk <[EMAIL PROTECTED]> wrote: > > Trustin Lee wrote: > > >> > > >>> You might encounter segfault due to a bug of the current > > >>> implementation because we are using tomcat-native bridge for > > >>> APR 1.2. Any feed back is welcome! > > >>> > > >> The problem is probably with shutting down the APR library. > > >> Tomcat-native is very thin JNI layer for APR, so some > > >> precautions must be taken, like implementing shutdown hooks. > > > > > > Yes, I found segfault happens when I try to close socket more > > > than once. :) > > > > > > > Right. All native 'objects' are long (actually pointers to the > > native memory), and the only check that is done is test for zero > > (NULL). It's the same as if you would call free() twice. The second > > call will probably core dump cause it references already > > deallocated memory. So, although harder to program correctly, it > > offers zero GC, cause no Java objects gets created. The same thing > > is done within core Java (rt.jar) where actual class implementation > > takes care of underlaying JNI safety. I was thinking to add the > > higher API over this thin layer that would allow Java programmers > > to use it more comfortably, but then extra Java objects would be > > created, and memory usage as well as GC would rise. So, when using > > tomcat-native, think as a C not as Java programmer ;) > > Yes, playing with APR reminded me of the old days. :D You probably mean the "good" old days ;) > > > Next, the major problem is in threaded environment where you can > > call global Pool destroy (shutting down the Library) while there is > > still native call in progress. > > > > First thing I would add would be the unlock for Socket.accept > > (something each Acceptor, not only APR should have) > > and make sure that Socket.close for the acceptor socket is called > > even on the CTRL+C. After all native calls are exited, then you can > > safely call the Library.shutdown > > Doesn't OS release any resources allocated by a process when the > process quits or dies? Do I really need to call Library.shutdown()? > Am I missing something? Yes it's supposed to free it, but it's a good idea to unalloc everything when the process quit, it helps to track leaks. > Thanks again for the feed back, > Trustin Thanks you for revamping it :) Julien
