Comment 7 for bug 1604335

Reviewed: https://review.openstack.org/345120
Committed: https://git.openstack.org/cgit/openstack/swift/commit/?id=2876f59d4cdbafc297d79f4e6295f05e3448ae47
Submitter: Jenkins
Branch: master

commit 2876f59d4cdbafc297d79f4e6295f05e3448ae47
Author: Kota Tsuyuzaki <email address hidden>
Date: Wed Jul 20 18:16:27 2016 -0700

    Cache fragment size for EC policy

    ECStoragePolicy.fragment_size is never changed on running Swift because
    it is from ec_segment_size and ec_type defined in swift.conf statically
    so let's cache the value after retrieving the value from the pyeclib driver.

    And more, pyeclib <= 1.2.1 (current newest) has a bug [1] to leak the reference
    count of the items in the returned dict (i.e. causes memory leak) so that
    this caching will be mitigation of the memory leak because this saves the call
    count fewer than current as possible.

    Note that the complete fix for the memory leak for pyeclib is proposed at
    https://review.openstack.org/#/c/344066/

    1: https://bugs.launchpad.net/pyeclib/+bug/1604335

    Related-Bug: #1604335
    Change-Id: I6bbaa4063dc462383c949764b6567b2bee233689