1. 01 8月, 2014 2 次提交
  2. 30 7月, 2014 1 次提交
    • E
      namespaces: Use task_lock and not rcu to protect nsproxy · 728dba3a
      Eric W. Biederman 提交于
      The synchronous syncrhonize_rcu in switch_task_namespaces makes setns
      a sufficiently expensive system call that people have complained.
      
      Upon inspect nsproxy no longer needs rcu protection for remote reads.
      remote reads are rare.  So optimize for same process reads and write
      by switching using rask_lock instead.
      
      This yields a simpler to understand lock, and a faster setns system call.
      
      In particular this fixes a performance regression observed
      by Rafael David Tinoco <rafael.tinoco@canonical.com>.
      
      This is effectively a revert of Pavel Emelyanov's commit
      cf7b708c Make access to task's nsproxy lighter
      from 2007.  The race this originialy fixed no longer exists as
      do_notify_parent uses task_active_pid_ns(parent) instead of
      parent->nsproxy.
      Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      728dba3a
  3. 21 7月, 2014 9 次提交
  4. 20 7月, 2014 11 次提交
  5. 19 7月, 2014 17 次提交