bootmem: respect goal more likely

[linux-2.6] / Documentation / md.txt

diff --git a/Documentation/md.txt b/Documentation/md.txt
index 5818628207b5ec8b5f32ed6d727857f5f6dcbbec..1da9d1b1793f3436b3561a48de7fbcd8c893e74e 100644 (file)
--- a/Documentation/md.txt
+++ b/Documentation/md.txt
@@ -236,6 +236,11 @@ All md devices contain:
      writing the word for the desired state, however some states
      cannot be explicitly set, and some transitions are not allowed.
 
      writing the word for the desired state, however some states
      cannot be explicitly set, and some transitions are not allowed.
 

+     Select/poll works on this file.  All changes except between
+       active_idle and active (which can be frequent and are not
+       very interesting) are notified.  active->active_idle is
+       reported if the metadata is externally managed.
+

      clear
          No devices, no size, no level
          Writing is equivalent to STOP_ARRAY ioctl
      clear
          No devices, no size, no level
          Writing is equivalent to STOP_ARRAY ioctl


@@ -292,6 +297,10 @@ Each directory contains:
              writemostly - device will only be subject to read
                         requests if there are no other options.
                         This applies only to raid1 arrays.
              writemostly - device will only be subject to read
                         requests if there are no other options.
                         This applies only to raid1 arrays.

+             blocked  - device has failed, metadata is "external",
+                        and the failure hasn't been acknowledged yet.
+                        Writes that would write to this device if
+                        it were not faulty are blocked.

              spare    - device is working, but not a full member.
                         This includes spares that are in the process
                         of being recovered to
              spare    - device is working, but not a full member.
                         This includes spares that are in the process
                         of being recovered to


@@ -301,6 +310,12 @@ Each directory contains:
        Writing "remove" removes the device from the array.
        Writing "writemostly" sets the writemostly flag.
        Writing "-writemostly" clears the writemostly flag.
        Writing "remove" removes the device from the array.
        Writing "writemostly" sets the writemostly flag.
        Writing "-writemostly" clears the writemostly flag.

+       Writing "blocked" sets the "blocked" flag.
+       Writing "-blocked" clear the "blocked" flag and allows writes
+               to complete.
+
+       This file responds to select/poll. Any change to 'faulty'
+       or 'blocked' causes an event.

 
       errors
        An approximate count of read errors that have been detected on
 
       errors
        An approximate count of read errors that have been detected on


@@ -332,7 +347,7 @@ Each directory contains:
         for storage of data.  This will normally be the same as the
        component_size.  This can be written while assembling an
         array.  If a value less than the current component_size is
         for storage of data.  This will normally be the same as the
        component_size.  This can be written while assembling an
         array.  If a value less than the current component_size is

-        written, component_size will be reduced to this value.
+        written, it will be rejected.

 
 
 An active md device will also contain and entry for each active device
 
 
 An active md device will also contain and entry for each active device


@@ -381,6 +396,19 @@ also have
        'check' and 'repair' will start the appropriate process
            providing the current state is 'idle'.
 
        'check' and 'repair' will start the appropriate process
            providing the current state is 'idle'.
 

+      This file responds to select/poll.  Any important change in the value
+      triggers a poll event.  Sometimes the value will briefly be
+      "recover" if a recovery seems to be needed, but cannot be
+      achieved. In that case, the transition to "recover" isn't
+      notified, but the transition away is.
+
+   degraded
+      This contains a count of the number of devices by which the
+      arrays is degraded.  So an optimal array with show '0'.  A
+      single failed/missing drive will show '1', etc.
+      This file responds to select/poll, any increase or decrease
+      in the count of missing devices will trigger an event.
+

    mismatch_count
       When performing 'check' and 'repair', and possibly when
       performing 'resync', md will count the number of errors that are
    mismatch_count
       When performing 'check' and 'repair', and possibly when
       performing 'resync', md will count the number of errors that are


@@ -416,6 +444,16 @@ also have
      sectors in total that could need to be processed.  The two
      numbers are separated by a '/'  thus effectively showing one
      value, a fraction of the process that is complete.
      sectors in total that could need to be processed.  The two
      numbers are separated by a '/'  thus effectively showing one
      value, a fraction of the process that is complete.

+     A 'select' on this attribute will return when resync completes,
+     when it reaches the current sync_max (below) and possibly at
+     other times.
+
+   sync_max
+     This is a number of sectors at which point a resync/recovery
+     process will pause.  When a resync is active, the value can
+     only ever be increased, never decreased.  The value of 'max'
+     effectively disables the limit.
+

 
    sync_speed
      This shows the current actual speed, in K/sec, of the current
 
    sync_speed
      This shows the current actual speed, in K/sec, of the current


@@ -440,3 +478,9 @@ These currently include
       there are upper and lower limits (32768, 16).  Default is 128.
   strip_cache_active (currently raid5 only)
       number of active entries in the stripe cache
       there are upper and lower limits (32768, 16).  Default is 128.
   strip_cache_active (currently raid5 only)
       number of active entries in the stripe cache

+  preread_bypass_threshold (currently raid5 only)
+      number of times a stripe requiring preread will be bypassed by
+      a stripe that does not require preread.  For fairness defaults
+      to 1.  Setting this to 0 disables bypass accounting and
+      requires preread stripes to wait until all full-width stripe-
+      writes are complete.  Valid values are 0 to stripe_cache_size.