Hello,
I am working a grpc client application (C++) to talk to grpc server on
remote:
1. First I use grpc::CreateChannel(...) to create a new channel instance
and it is successful:
auto spChannel = grpc::CreateChannel("unix:/tmp/test_sock",
grpc::InsecureChannelCredentials());
2. Then I check channel state:
auto chanState = spChannel->GetState(false);
if (chanState == GRPC_CHANNEL_IDLE)
{
spChannel->GetState(true); // this will trigger connect to server
}
3. It could be server side is not ready yet, as such the connect would
fail. Then I remove old channel and
create a new one in step 1).
spChannel = grpc::CreateChannel("unix:/tmp/test_sock",
grpc::InsecureChannelCredentials());
4. Repeat step 2) - 3) until server is up (backoff timing is omitted).
The logic above works without problem when server comes up later. However,
there is an issue when channel instance
is destroyed: the file descriptor id associated with channel is not freed.
Let's say if server comes up in a long time, the following complaint
from grpc lib tells us that no file description id available eventually:
Jun 08 04:00:28 conn[25285]: E0608 04:00:28.076832140 25285
ev_epoll_linux.c:1825] add_poll_object: {"
created":"@1496894428.076821026","description":"polling_island_create","file":"src/core/lib/iomgr/ev_epoll_linux.c","file_line":284,
"referenced_errors":[{"created":"@1496894428.076819933","description":"OS
Error","errno":24,"file":"src/core/lib/iomgr/ev_epoll_linu
x.c","file_line":561,"os_error":"Too many open
files","syscall":"epoll_create1"}]}{quote}
Tracing code to src/core/lib/iomgr/ev_epoll_linux.c, the function
polling_island_create() is the one to create file descriptor id (epoll_id).
However, the polling_island_delete(...) should be called when channel is
destroyed as well. Otherwise, the file descriptor ids will be
leaked and led to the above error.
Has anyone seen this ? Or I didn't use the grpc channel properly ?
Thanks,
Haiyang Yin
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