Direct Memory Buffer Leak in File IO #863
Description
Apparently the JRuby File class allocates NIO direct memory buffers, but doesn't release them. I wrote the following test program (on jruby-1.7.4 on Java 1.7 on OSX 10.8.4):
i=0
loop do
i=i+1
File.open('/dev/null','r') do |infile|
end
puts i
sleep 0.1
endWhen I run this with a restricted MaxDirectMemorySize using:
jruby -J-XX:MaxDirectMemorySize=200K -w leak.rb
it crashes very quickly:
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Error: Your application used more memory than the safety cap of 500M.
Specify -J-Xmx####m to increase it (#### = cap size in MB).
Exception trace follows:
java.lang.OutOfMemoryError: Direct buffer memory
at java.nio.Bits.reserveMemory(Bits.java:658)
at java.nio.DirectByteBuffer.<init>(DirectByteBuffer.java:123)
at java.nio.ByteBuffer.allocateDirect(ByteBuffer.java:306)
at org.jruby.util.io.ChannelDescriptor.<init>(ChannelDescriptor.java:663)
at org.jruby.util.io.ChannelDescriptor.<init>(ChannelDescriptor.java:217)
at org.jruby.util.io.ChannelDescriptor.open(ChannelDescriptor.java:797)
at org.jruby.RubyFile.sysopen(RubyFile.java:1242)
at org.jruby.RubyFile.sysopenInternal(RubyFile.java:1199)
at org.jruby.RubyFile.openFile19(RubyFile.java:1150)
at org.jruby.RubyFile.initialize19(RubyFile.java:334)
at org.jruby.RubyFile$INVOKER$i$0$2$initialize19.call(RubyFile$INVOKER$i$0$2$initialize19.gen)
at org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:79)
at org.jruby.runtime.callsite.CachingCallSite.call(CachingCallSite.java:85)
at org.jruby.RubyClass.newInstance(RubyClass.java:876)
at org.jruby.RubyIO.open(RubyIO.java:1144)
at org.jruby.RubyIO$INVOKER$s$0$0$open.call(RubyIO$INVOKER$s$0$0$open.gen)
at org.jruby.internal.runtime.methods.DynamicMethod.call(DynamicMethod.java:217)
at org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:211)
at org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:222)
at leak.block_0$RUBY$__file__(leak.rb:6)
at leak$block_0$RUBY$__file__.call(leak$block_0$RUBY$__file__)
at org.jruby.runtime.CompiledBlock19.yieldSpecificInternal(CompiledBlock19.java:117)
at org.jruby.runtime.CompiledBlock19.yieldSpecific(CompiledBlock19.java:92)
at org.jruby.runtime.Block.yieldSpecific(Block.java:111)
at org.jruby.RubyKernel.loop(RubyKernel.java:1489)
at org.jruby.RubyKernel$INVOKER$s$0$0$loop.call(RubyKernel$INVOKER$s$0$0$loop.gen)
at org.jruby.runtime.callsite.CachingCallSite.cacheAndCall(CachingCallSite.java:316)
at org.jruby.runtime.callsite.CachingCallSite.callBlock(CachingCallSite.java:145)
at org.jruby.runtime.callsite.CachingCallSite.callIter(CachingCallSite.java:154)
at leak.__file__(leak.rb:4)
at leak.load(leak.rb)
at org.jruby.Ruby.runScript(Ruby.java:807)
at org.jruby.Ruby.runScript(Ruby.java:800)
at org.jruby.Ruby.runNormally(Ruby.java:669)
at org.jruby.Ruby.runFromMain(Ruby.java:518)
at org.jruby.Main.doRunFromMain(Main.java:390)
at org.jruby.Main.internalRun(Main.java:279)
at org.jruby.Main.run(Main.java:221)
at org.jruby.Main.main(Main.java:201)
I tried the same thing by simply opening and closing a FileInputStream, and the memory usage stays constant. I used https://blogs.oracle.com/nbprofiler/entry/new_memory_buffer_plugin_for to monitor buffer usage.