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  1. 23 Aug, 2010 8 commits
    • Vivek Goyal's avatar
      cfq-iosched: Do group share accounting in IOPS when slice_idle=0 · 02b35081
      Vivek Goyal authored 
      o Implement another CFQ mode where we charge group in terms of number
  of requests dispatched instead of measuring the time. Measuring in terms
  of time is not possible when we are driving deeper queue depths and there
  are requests from multiple cfq queues in the request queue.

o This mode currently gets activated if one sets slice_idle=0 and associated
  disk supports NCQ. Again the idea is that on an NCQ disk with idling disabled
  most of the queues will dispatch 1 or more requests and then cfq queue
  expiry happens and we don't have a way to measure time. So start providing
  fairness in terms of IOPS.

o Currently IOPS mode works only with cfq group scheduling. CFQ is following
  different scheduling algorithms for queue and group scheduling. These IOPS
  stats are used only for group scheduling hence in non-croup mode nothing
  should change.

o For CFQ group scheduling one can disable slice idling so that we don't idle
  on queue and drive deeper request queue depths (achieving better throughput),
  at the same time group idle is enabled so one should get service
  differentiation among groups.
Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
Acked-by: default avatarJeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      02b35081
    • Vivek Goyal's avatar
      cfq-iosched: Do not idle if slice_idle=0 · b6508c16
      Vivek Goyal authored 
      Do not idle either on cfq queue or service tree if slice_idle=0. User does
not want any queue or service tree idling. Currently even if slice_idle=0,
we were waiting for request to finish before expiring the queue and that
can lead to lower queue depths.
Acked-by: default avatarJeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      b6508c16
    • Stephen M. Cameron's avatar
      cciss: disable doorbell reset on reset_devices · 75230ff2
      Stephen M. Cameron authored 
      The doorbell reset initially appears to work correctly,
the controller resets, comes up, some i/o can even be
done, but on at least some Smart Arrays in some servers,
it eventually causes a subsequent controller lockup due
to some kind of PCIe error, and kdump can end up leaving
the root filesystem in an unbootable state.  For this
reason, until the problem is fixed, or at least isolated
to certain hardware enough to be avoided, the doorbell
reset should not be used at all.
Signed-off-by: default avatarStephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      75230ff2
    • Ciju Rajan K's avatar
      blkio: Fix return code for mkdir calls · 96aa1b41
      Ciju Rajan K authored 
      If the cgroup hierarchy for blkio control groups is deeper than two
levels, kernel should not allow the creation of further levels. mkdir
system call does not except EINVAL as a return value. This patch
replaces EINVAL with more appropriate EPERM
Signed-off-by: default avatarCiju Rajan K <ciju@linux.vnet.ibm.com>
Reviewed-by: default avatarKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
      96aa1b41
    • Linus Torvalds's avatar
      Merge branch 'radix-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev · 9ee47476
      Linus Torvalds authored 
      * 'radix-tree' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/xfsdev:
  radix-tree: radix_tree_range_tag_if_tagged() can set incorrect tags
  radix-tree: clear all tags in radix_tree_node_rcu_free
      9ee47476
    • Linus Torvalds's avatar
      Linux 2.6.36-rc2 · 76be97c1
      Linus Torvalds authored
      76be97c1
    • Dave Chinner's avatar
      radix-tree: radix_tree_range_tag_if_tagged() can set incorrect tags · 144dcfc0
      Dave Chinner authored 
      Commit ebf8aa44 ("radix-tree:
omplement function radix_tree_range_tag_if_tagged") does not safely
set tags on on intermediate tree nodes. The code walks down the tree
setting tags before it has fully resolved the path to the leaf under
the assumption there will be a leaf slot with the tag set in the
range it is searching.

Unfortunately, this is not a valid assumption - we can abort after
setting a tag on an intermediate node if we overrun the number of
tags we are allowed to set in a batch, or stop scanning because we
we have passed the last scan index before we reach a leaf slot with
the tag we are searching for set.

As a result, we can leave the function with tags set on intemediate
nodes which can be tripped over later by tag-based lookups. The
result of these stale tags is that lookup may end prematurely or
livelock because the lookup cannot make progress.

The fix for the problem involves reocrding the traversal path we
take to the leaf nodes, and only propagating the tags back up the
tree once the tag is set in the leaf node slot. We are already
recording the path for efficient traversal, so there is no
additional overhead to do the intermediately node tag setting in
this manner.

This fixes a radix tree lookup livelock triggered by the new
writeback sync livelock avoidance code introduced in commit
f446daae ("mm: implement writeback
livelock avoidance using page tagging").
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Acked-by: default avatarJan Kara <jack@suse.cz>
      144dcfc0
    • Dave Chinner's avatar
      radix-tree: clear all tags in radix_tree_node_rcu_free · b6dd0865
      Dave Chinner authored 
      Commit f446daae ("mm: implement
writeback livelock avoidance using page tagging") introduced a new
radix tree tag, increasing the number of tags in each node from 2 to
3. It did not, however, fix up the code in
radix_tree_node_rcu_free() that cleans up after radix_tree_shrink()
and hence could leave stray tags set in the new tag array.

The result is that the livelock avoidance code added in the the
above commit would hit stale tags when doing tag based lookups,
resulting in livelocks when trying to traverse the tree.

Fix this problem in radix_tree_node_rcu_free() so it doesn't happen
again in the future by using a loop to walk all the tags up to
RADIX_TREE_MAX_TAGS to clear the stray tags radix_tree_shrink()
leaves behind.
Signed-off-by: default avatarDave Chinner <dchinner@redhat.com>
Acked-by: default avatarNick Piggin <npiggin@kernel.dk>
Acked-by: default avatarJan Kara <jack@suse.cz>
      b6dd0865
  3. 22 Aug, 2010 12 commits
  5. 21 Aug, 2010 6 commits
  7. 20 Aug, 2010 14 commits
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