Commit 0015190a authored by Mike Rapoport's avatar Mike Rapoport Committed by Jonathan Corbet
Browse files

docs/vm: soft-dirty.txt: convert to ReST format 



Signed-off-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
parent 0c14398b

Documentation/vm/soft-dirty.txt

+12 −8
Original line number Diff line number Diff line 
                            SOFT-DIRTY PTEs

.. _soft_dirty:



===============

Soft-Dirty PTEs

===============



The soft-dirty is a bit on a PTE which helps to track which pages a task

writes to. In order to do this tracking one should



  1. Clear soft-dirty bits from the task's PTEs.



     This is done by writing "4" into the /proc/PID/clear_refs file of the

     This is done by writing "4" into the ``/proc/PID/clear_refs`` file of the

     task in question.



  2. Wait some time.



  3. Read soft-dirty bits from the PTEs.



     This is done by reading from the /proc/PID/pagemap. The bit 55 of the

     This is done by reading from the ``/proc/PID/pagemap``. The bit 55 of the

     64-bit qword is the soft-dirty one. If set, the respective PTE was

     written to since step 1.