Fix memory leak in streams

[vloup]

As suggested by @JamesColeman-LW, here is a PR that fixes #2208.

All the credits goes to @marcstern for finding the root cause of the memory leak, I just did share my memory graph and added an extra ifdef.

[vloup]

Any news on this PR? I did a rebase since CHANGES was in conflict with v2/master. I know that @JamesColeman-LW is interested to get this merged.

[JamesColeman-LW]

I pushed this to our fleet and we definitely saw a large drop in memory usage.

Valgrind ms traces before:

[1336][root@esg-test02 valgrind]$ ms_print massif.out.657
--------------------------------------------------------------------------------
Command:            /usr/sbin/httpd -DSSL -DFOREGROUND
Massif arguments:   (none)
ms_print arguments: massif.out.657
--------------------------------------------------------------------------------


    MB
144.9^                                                                       #
     |                                                                 @ @:@:#
     |                                                           @ @:@:@:@:@:#
     |                                                    :@ @:@:@:@:@:@:@:@:#
     |                                              :@:@:@:@:@:@:@:@:@:@:@:@:#
     |                                        :@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |                                  :@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |                          :@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |                    :@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |                    @@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |       :@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |       :@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |       :@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |      @:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |     @@:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |     @@:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |    @@@:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |    @@@:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |   @@@@:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
     |  @@@@@:@::::::::@::@@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:@:#
   0 +----------------------------------------------------------------------->Gi
     0                                                                   6.584

Number of snapshots: 94
 Detailed snapshots: [3, 4, 5, 7, 8, 9, 12, 23, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93 (peak)]

After patch applied:

[1312][root@esg-test02 valgrind]$ ms_print massif.out.13391
--------------------------------------------------------------------------------
Command:            /usr/sbin/httpd -DSSL -DFOREGROUND
Massif arguments:   (none)
ms_print arguments: massif.out.13391
--------------------------------------------------------------------------------


    MB
87.29^                                              :
     |                   @#::::::::::@:::::::::@::::::::::@:::::::::@::::::::@
     |                   @#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |          :     :::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |       ::::::::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |      :: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |      :: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |      @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |      @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |      @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |      @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |    @@@: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |    @ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |    @ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |    @ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |   @@ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |   @@ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |   @@ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |   @@ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
     |  :@@ @: ::: ::::::@#::::::::::@:::::::::@::::::::::@:::::::::@:::: : :@
   0 +----------------------------------------------------------------------->Gi
     0                                                                   6.969

Number of snapshots: 74
 Detailed snapshots: [3, 5, 6, 18, 19 (peak), 31, 41, 53, 63, 73]