git: kernel - Performance optimization pass

[Matthew Dillon]

commit b7ebebd18bb9366e6938415e2030c9ee7fdff081
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Fri Oct 11 10:48:43 2013 -0700

    kernel - Performance optimization pass
    
    * Numerous pid and priority related syscalls, such as getpid(), were
      improperly acquiring proc_token to protect fields that are now protected
      with per-process or per-pgrp tokens.
    
      Do a pass on kern_prot.c and kern_resource.c fixing these issues.  This
      removes the use of proc_token from several common system call paths but
      it should be noted that none of these system calls are in critical paths.
      The benefit is probably minor but will improve performance in the face
      of allproc-scanning operations (such as when you do a 'ps' or 'top').
    
    * vmntvnodescan() is not in the critical path except for vflush()'s which
      occur on umount.  vflush()'s pass a NULL fast function.  The
      vmntvnodescan() only needs to hold the vmobj_token when the fastfunc is
      non-NULL.  Do not hold the vmobj_token when fastfunc is NULL.
    
      This primarily improves performance when tmpfs's are being mounted and
      unmounted at a high rate (poudriere bulk builds).

Summary of changes:
 sys/kern/kern_prot.c     |  35 +++++---
 sys/kern/kern_resource.c | 224 ++++++++++++++++++++++++++---------------------
 sys/kern/kern_sig.c      |   2 +-
 sys/kern/vfs_mount.c     |   9 +-
 4 files changed, 156 insertions(+), 114 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/b7ebebd18bb9366e6938415e2030c9ee7fdff081


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