RFR 8021820: Number of opened files used in select() is limited to 1024 [macosx]

Chris Hegarty chris.hegarty at oracle.com
Wed Jul 31 14:25:35 UTC 2013

On 31/07/2013 14:45, Alan Bateman wrote:
> On 31/07/2013 05:18, Aleksej Efimov wrote:
>> Hi,
>> Can I have a review for the following problem:
>> The MACOSX JDK (more precisely - the java.net classes) uses the
>> select() system call to wait for different events on sockets fds. And
>> the default behaviour for select() on Darwin is to fail when fdset
>> contains the fd with id greater than FDSET_SIZE(=1024). Test case in
>> webrev illustrates this behavior.
>> There is at least one solution for it: use -D_DARWIN_UNLIMITED_SELECT
>> compilation flag for all macosx sources: this won't affect other parts
>> of JDK because they are not using select().
>> Currently, I have added this compilation flag to
>> common/autoconf/generated-configure.sh and
>> common/autoconf/generated-configure.sh. I wonder, if there is a better
>> place where I can put this flag?
>> The webrev: http://cr.openjdk.java.net/~aefimov/8021820/webrev.00/
>> BUG: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8021820
> Thanks for looking into this one. The build changes look okay to me but


> it's probably best that someone on build-dev agree to those. Michael
> McMahon can probably explain why the net code is using select for timed
> read/accept (I have a vague recollection of there being an issue with
> poll due to the way that it is implemented on kqueue with the result
> that it had to be changed to use select).

I don't remember the the specifics either, but that sounds familiar.


> I think the test needs re-work. It looks to me that the it attempts to
> connect to an Oracle internal site so that's not going to work
> everywhere. In general we don't want the tests to be dependent on hosts
> that may or may not exist (we had tests that used to this in the past
> but they caused a lot of grief). It also looks like the test doesn't
> close the 1023 files that it opens at the start and so I assume this
> test will always fail on Windows when jtreg tries to clean-up.
> -Alan.

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