git: kernel - Minor pmap optimizations, minor swap_pager*() optimizations

Matthew Dillon dillon at crater.dragonflybsd.org
Wed Mar 4 09:26:39 PST 2020


commit 427fbc33cbe32c67bca95139922cca56028464a0
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date:   Wed Mar 4 09:23:09 2020 -0800

    kernel - Minor pmap optimizations, minor swap_pager*() optimizations
    
    * Avoid the atomic_fcmpset_int() in pmap_enter() if the page already
      has the appropriate PG_* bits set.  Because the page is soft-busied,
      this check should not be able to race any clearing of the bits (which
      can only be done when the page is hard-busied).
    
    * swap_pager_freespace*() no longer bothers to acquire the object
      token if the object's swblock_count is 0.
    
    * Misc __read_* optimizations
    
    * Misc __predict* optimizations

Summary of changes:
 sys/platform/pc64/x86_64/pmap.c | 23 +++++++++++++++--------
 sys/vm/swap_pager.c             |  4 ++++
 2 files changed, 19 insertions(+), 8 deletions(-)

http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/427fbc33cbe32c67bca95139922cca56028464a0


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