On Tue, 15 Jun 2021 08:58:45 GMT, Chris Hegarty <che...@openjdk.org> wrote:
>> JDK-8265369 [macos-aarch64] java/net/MulticastSocket/Promiscuous.java failed
>> with "SocketException: Cannot allocate memory"
>>
>> The test java/net/MulticastSocket/Promiscuous.java has been observed to fail
>> on a regular basis on macosx-aarch.
>> This is typically under heavy test load on a test machine. Analysis of the
>> problem have
>> shown that the setsockopt for joining a multicast group will intermittently
>> fail with ENOMEM.
>>
>> While analysis of test environment shows significant memory usage and some
>> memory pressure, it is
>> not excessive and as such it is deemed transition or temporary condition,
>> such that a retry of the
>> setsockopt system call, has been seen to mitigate the issue. This adds to
>> the stability of the
>> Promiscuous.java test and reduces test failure noise.
>>
>> The proposed fix is in
>> open/src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c
>> in the mcast_join_leave function. That is, if setsockopt to join an mcast
>> group fails, and the errno == ENOMEM,
>> then re-invoke the setsockopt system call for joining a mcast group.
>> The change has been applied as a conditional compilation.
>> Additionally this change result in the Promiscuous.java test being removed
>> from the
>> ProblemList.txt.
>>
>> Please oblige and review the changes for a fix of the issue JDK-8265369
>
> src/java.base/unix/native/libnet/PlainDatagramSocketImpl.c line 2017:
>
>> 2015: }
>> 2016: } else {
>> 2017: #endif
>
> The handling of ENOMEM here is consistent with how it is handled in the NIO
> area - good.
>
> I wonder if a little restructuring may simplify the call flow? For example,
> something similar to:
>
> int n;
> ...
> /*
> * Join the multicast group.
> */
> n = setsockopt(fd, IPPROTO_IP, (join ?
> IP_ADD_MEMBERSHIP:IP_DROP_MEMBERSHIP),
> (char *) &mname, mname_len);
> #ifdef __APPLE__
> // workaround macOS bug where IP_ADD/DROP_MEMBERSHIP fails intermittently
> if (n < 0 && errno == ENOMEM) {
> n = setsockopt(fd, IPPROTO_IP, (join ?
> IP_ADD_MEMBERSHIP:IP_DROP_MEMBERSHIP),
> (char *) &mname, mname_len);
> }
> #endif
>
> if (n < 0) { ...
yes, I'll do that ... originally I did this but reverted to current change to
retain the current structure of the file
thanks for the suggestion, it is much neater
-------------
PR: https://git.openjdk.java.net/jdk17/pull/44
