                 Information about /proc/ppc_htab
=====================================================================

This entry in the proc directory is readable by all users but only
writable by root.


1. Reading

  Reading this file will give you information about the memory management
  hash table that serves as an extended tlb for page translation on the
  powerpc.

  Explaination of the fields:

    Size - hash table size in Kb.
    Buckets -  number of buckets in the table.
    Addess - the virtual kernel address of the hash table base.
    Entries - the number of ptes that can be stored in the hash table.
    User/Kernel - how many pte's are in use by the kernel or user at that time.
    Overflows - How many of the entries are in their secondary hash location.
    Percent full - ratio of free pte entries to in use entries.

  Note that calculation of the data displayed from /proc/ppc_htab takes
  a long time and spends a great deal of time in the kernel.  It would
  be quite hard on performance to read this file constantly.  In time
  there may be a counter in the kernel that allows successive reads from
  this file only after a given amount of time has passed to reduce the
  possibility of a user slowing the system by reading this file.

2. Writing

  Writing to ppc_htab is not yet allowed.

  Write options to ppc_htab:
  
   - To set the size of the hash table to 64Kb:

      echo 'size 64' > /dev/ppc_htab

     The size must be a multiple of 64 and must be greater than or equal to
     64.








