Description of problem:
This is a bug that reported into glibc in 2011. It has been fixed in glibc, but this commit ha not made it into the CentOS release of glibc as of glibc-2.12-1.166.el6_7.3.x86_64.

Here is a link to the original BZ for glibc: https://sourceware.org/bugzilla/show_bug.cgi?id=12907 [^]

We are now configuring over 10k IPs on the same server, and this has been killing us. As a temporary fix, I patched glibc-2.12-1.166.el6_7.3.x86_64 with Ulrich's patch and have been running it in our production environment.

Here is the specific glibc commit info:
commit fa3fc0fe5f452d0aa7e435d8f32e992958683819
Author: Ulrich Drepper <drepper@gmail.com>
Date: Wed Jun 22 15:00:54 2011 -0400

    Avoid __check_pf calls in getaddrinfo unless really needed

Can we please get this added into the next release of glibc?

Version-Release number of selected component (if applicable):
glibc-2.12-1.166.el6_7.3.x86_64

How reproducible:

From the original glibc BZ report:

- configure lots of addresses
#!/usr/bin/perl
my $addrCount = 64000;
for (my $i=1; $i < $addrCount; $i++) {
  my $w1 = ($i % 254) + 1;
  my $w2 = ($i / 254) + 1;
  my $s = sprintf("ip addr add 10.5.%d.%d dev eth0", $w2, $w1);
  print "$s\n";
  system ($s)
} 
- resolve a literal address
  struct addrinfo ai;
  struct addrinfo *ailist = NULL;
  memset(&ai, 0, sizeof(ai));
  ai.ai_family = af;
  ai.ai_flags = AI_PASSIVE;
  getaddrinfo("10.5.1.1", "0", &ai, &ailist);
  freeaddrinfo(ailist);

Actual results:
Takes a very long time to spin through the inventory of IP addresses.

Expected results:


Additional info: