cvs commit: src/sys/amd64/amd64 pmap.c

[Alan Cox]

alc         2008-01-14 21:25:06 UTC

  FreeBSD src repository

  Modified files:
    sys/amd64/amd64      pmap.c 
  Log:
  Make pmap_is_prefaultable() more TLB friendly.  Specifically, make it use
  the kernel's direct map instead of the pmap's recursive mapping to access
  the lowest level in the page table.  The direct map is preferable for two
  reasons: (1) The TLB is more likely to hold the required direct mapping
  because pmap_enter() has already used the direct map to access a nearby
  PTE and (2) loading a direct mapping into the TLB involves walking only 2
  or 3 levels of the page table instead of 4.
  
  Revision  Changes    Path
  1.604     +1 -1      src/sys/amd64/amd64/pmap.c