Alexander, is it related to newcodemodel only? I'm not aware of any changes in attachFileListeners (i.e. adding new extra listeners for apt.use.clank=true mode)

may be linux machine is not completely configured to provide more opened file descriptors?

(In reply to Vladimir Voskresensky from comment #2)
> may be linux machine is not completely configured to provide more opened
> file descriptors?
Question: Why new code model start to consume more file descriptors?

It doesn't. I see that addWatch has problems and addWatch is called before parse

Can you recheck, please, that we still has such issue in logs

fresh log:

WARNING [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/deps: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/deps errno: 28
WARNING [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/deps: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/deps errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/jarreorder: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/jarreorder errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/jarreorder: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/jarreorder errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/stripproperties: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/stripproperties errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/stripproperties: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/stripproperties errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/addtorestrictedpkgs: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/addtorestrictedpkgs errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/addtorestrictedpkgs: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/addtorestrictedpkgs errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata/awt: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata/awt errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Cannot add filesystem watch for /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata/awt: java.io.IOException: addWatch on /export/home/tester/test_projects/jdk_trunk/jdk/make/src/classes/build/tools/icondata/awt errno: 28
INFO [org.netbeans.modules.masterfs.watcher.Watcher]: Following "Cannot add filesystem watch" will be logged with log level FINE.

hopefully fixed by
https://hg.kenai.com/hg/sputnik~main/rev/945b665df24a
in the line marked as
+      // JAVA: we close mapped file here to not keep opened file descriptors
+      MFR.$destroy();

http://hg.netbeans.org/cnd-main/rev/5fb562071bab

Integrated into 'main-silver', will be available in build *201509060314* on http://bits.netbeans.org/dev/nightly/ (upload may still be in progress)

Changeset: http://hg.netbeans.org/main-silver/rev/5fb562071bab
User: Vladimir Voskresensky <vv159170@netbeans.org>
Log: update binaries
- fixed #254962 - [newcodemodel] Code model uses dead objects (java.lang.ArrayIndexOutOfBoundsException: 4096)
and hopefully
- fixed #253714 - [newcodemodel] lack of watchers

not fixed

Remaining is related to not enough default file descriptor value on Linux system which is recommended to be increased for big source roots.
New code Model loads extra jar files and looks like it overflows available descriptors