1. 06 Oct, 2014 5 commits
    • Heinz Mauelshagen's avatar
      dm raid: add discard support for RAID levels 1 and 10 · 75b8e04b
      Heinz Mauelshagen authored
      
      
      Discard support is not enabled for RAID levels 4, 5, and 6 at this time
      due to concerns about unreliable discard_zeroes_data support on some
      hardware.  Otherwise, discards could cause stripe data corruption
      (classic example of bad apples spoiling the bunch).
      
      Signed-off-by: default avatarHeinz Mauelshagen <heinzm@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      75b8e04b
    • Benjamin Marzinski's avatar
      dm: allow active and inactive tables to share dm_devs · 86f1152b
      Benjamin Marzinski authored
      
      
      Until this change, when loading a new DM table, DM core would re-open
      all of the devices in the DM table.  Now, DM core will avoid redundant
      device opens (and closes when destroying the old table) if the old
      table already has a device open using the same mode.  This is achieved
      by managing reference counts on the table_devices that DM core now
      stores in the mapped_device structure (rather than in the dm_table
      structure).  So a mapped_device's active and inactive dm_tables' dm_dev
      lists now just point to the dm_devs stored in the mapped_device's
      table_devices list.
      
      This improvement in DM core's device reference counting has the
      side-effect of fixing a long-standing limitation of the multipath
      target: a DM multipath table couldn't include any paths that were unusable
      (failed).  For example: if all paths have failed and you add a new,
      working, path to the table; you can't use it since the table load would
      fail due to it still containing failed paths.  Now a re-load of a
      multipath table can include failed devices and when those devices become
      active again they can be used instantly.
      
      The device list code in dm.c isn't a straight copy/paste from the code in
      dm-table.c, but it's very close (aside from some variable renames).  One
      subtle difference is that find_table_device for the tables_devices list
      will only match devices with the same name and mode.  This is because we
      don't want to upgrade a device's mode in the active table when an
      inactive table is loaded.
      
      Access to the mapped_device structure's tables_devices list requires a
      mutex (tables_devices_lock), so that tables cannot be created and
      destroyed concurrently.
      
      Signed-off-by: default avatarBenjamin Marzinski <bmarzins@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      86f1152b
    • Benjamin Marzinski's avatar
      dm mpath: stop queueing IO when no valid paths exist · 1f271972
      Benjamin Marzinski authored
      
      
      'queue_io' is set so that IO is queued while paths are being
      initialized.  Clear queue_io in __choose_pgpath if there are no valid
      paths, since there are obviously no paths that can be initialized.
      Otherwise IOs to the device will back up.
      
      Signed-off-by: default avatarBenjamin Marzinski <bmarzins@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      1f271972
    • Junichi Nomura's avatar
      dm: use bioset_create_nobvec() · 3d8aab2d
      Junichi Nomura authored
      
      
      Since DM core uses bio_clone_fast() for both bio-based and request-based
      DM devices there is no need for DM's bioset to have a bvec mempool.
      
      With this patch, on arch with 4KB page for example, memory usage will be
      reduced by 64KB for each bio-based DM device and 1MB for each
      request-based DM device.
      
      For example, when you create 10,000 bio-based DM devices and 1,000
      request-based DM devices, memory usage of biovec under no load is:
        # grep biovec /proc/slabinfo
      
        biovec-256        418068 418068   4096  ...
        biovec-128             0      0   2048  ...
        biovec-64              0      0   1024  ...
        biovec-16              0      0    256  ...
      
      With this patch series applied, the usage becomes:
        # grep biovec /proc/slabinfo
      
        biovec-256           116    116   4096  ...
        biovec-128             0      0   2048  ...
        biovec-64              0      0   1024  ...
        biovec-16              0      0    256  ...
      
      So 4096 * (418068 - 116) = 1.6GB of memory is saved in this example.
      
      Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      3d8aab2d
    • Junichi Nomura's avatar
      dm: remove nr_iovecs parameter from alloc_tio() · 99778273
      Junichi Nomura authored
      
      
      alloc_tio() uses bio_alloc_bioset() to allocate a clone-bio for a bio.
      alloc_tio() takes the number of bvecs to allocate for the clone-bio.
      However, with v3.14's immutable biovec changes DM now uses
      __bio_clone_fast() and no longer needs to allocate bvecs.
      
      In practice, the 'nr_iovecs' passed to alloc_tio() is always effectively
      0.  __clone_and_map_simple_bio() looked like it was passing non-zero
      nr_iovecs, but its value was always within the range of inline bvecs and
      no allocation actually happened.  If allocation happened, the BUG_ON() in
      __bio_clone_fast() would've triggered.
      
      Remove the nr_iovecs parameter from alloc_tio() to prevent possible
      future bio_alloc_bioset() mis-use of a new bioset interface that will no
      longer allow bvecs to be allocated.
      
      Also fix extra whitespace before the __bio_clone_fast() call in
      __clone_and_map_simple_bio().
      
      Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      99778273
  2. 03 Oct, 2014 2 commits
  3. 01 Oct, 2014 1 commit
  4. 30 Sep, 2014 1 commit
  5. 27 Sep, 2014 14 commits
  6. 25 Sep, 2014 10 commits
  7. 22 Sep, 2014 7 commits