linux-toradex.git/block, branch v2.6.30-rc5

cfq-iosched: cache prio_tree root in cfqq->p_root

2009-04-24T06:54:22+00:00

Currently we look it up from ->ioprio, but ->ioprio can change if
either the process gets its IO priority changed explicitly, or if
cfq decides to temporarily boost it. So if we are unlucky, we can
end up attempting to remove a node from a different rbtree root than
where it was added.

Fix this by using ->org_ioprio as the prio_tree index, since that
will only change for explicit IO priority settings (not for a boost).
Additionally cache the rbtree root inside the cfqq, then we don't have
to add code to reinsert the cfqq in the prio_tree if IO priority changes.

Signed-off-by: Jens Axboe

cfq-iosched: fix bug with aliased request and cooperation detection

2009-04-24T06:54:22+00:00

cfq_prio_tree_lookup() should return the direct match, yet it always
returns zero. Fix that.

cfq_prio_tree_add() assumes that we don't get a direct match, while
it is very possible that we do. Using O_DIRECT, you can have different
cfqq with matching requests, since you don't have the page cache
to serialize things for you. Fix this bug by only adding the cfqq if
there isn't an existing match.

Signed-off-by: Jens Axboe

cfq-iosched: clear ->prio_trees[] on cfqd alloc

2009-04-24T06:54:22+00:00

Not strictly needed, but we should make it clear that we init the
rbtree roots here.

Signed-off-by: Jens Axboe

block: fix intermittent dm timeout based oops

2009-04-24T06:54:21+00:00

Very rarely under stress testing of dm, oopses are occuring as
something tampers with an old stack frame.  This has been traced back
to blk_abort_queue() leaving a timeout_list pointing to the stack.
The reason is that sometimes blk_abort_request() won't delete the
timer (if the request is marked as complete but before the timer has
been removed, a small race window).  Fix this by splicing back from
the ususally empty list to the q->timeout_list.

Signed-off-by: Hannes Reinecke 
Signed-off-by: Jens Axboe

block: simplify I/O stat accounting

2009-04-24T06:54:21+00:00

This simplifies I/O stat accounting switching code and separates it
completely from I/O scheduler switch code.

Requests are accounted according to the state of their request queue
at the time of the request allocation. There is no need anymore to
flush the request queue when switching I/O accounting state.

Signed-off-by: Jerome Marchand 
Signed-off-by: Jens Axboe

cfq-iosched: use the default seek distance when there aren't enough seek samples

2009-04-22T06:35:11+00:00

If the cfq io context doesn't have enough samples yet to provide a mean
seek distance, then use the default threshold we have for seeky IO instead
of defaulting to 0.

Signed-off-by: Jeff Moyer 
Signed-off-by: Jens Axboe

cfq-iosched: make seek_mean converge more quickly

2009-04-22T06:35:11+00:00

Right now, depending on the first sector to which a process issues I/O,
the seek time may start out way out of whack. So make sure we start
with 0 sectors in seek, instead of the offset of the first request
issued.

Signed-off-by: Jeff Moyer 
Signed-off-by: Jens Axboe

block: make blk_abort_queue() ignore non-request based devices

2009-04-22T06:35:10+00:00

There's nothing to do for those devices, since the timeout handling is
based on requests.

Signed-off-by: Jens Axboe

block: include empty disks in /proc/diskstats

2009-04-22T06:35:10+00:00

/proc/diskstats used to show stats for all disks whether they're
zero-sized or not and their non-zero partitions.  Commit
074a7aca7afa6f230104e8e65eba3420263714a5 accidentally changed the
behavior such that it doesn't print out zero sized disks.  This patch
implements DISK_PITER_INCL_EMPTY_PART0 flag to partition iterator and
uses it in diskstats_show() such that empty part0 is shown in
/proc/diskstats.

Reported and bisectd by Dianel Collins.

Signed-off-by: Tejun Heo 
Reported-by: Daniel Collins 
Signed-off-by: Jens Axboe

block: fix queue bounce limit setting

2009-04-22T06:35:09+00:00

Impact: don't set GFP_DMA in q->bounce_gfp unnecessarily

All DMA address limits are expressed in terms of the last addressable
unit (byte or page) instead of one plus that.  However, when
determining bounce_gfp for 64bit machines in blk_queue_bounce_limit(),
it compares the specified limit against 0x100000000UL to determine
whether it's below 4G ending up falsely setting GFP_DMA in
q->bounce_gfp.

As DMA zone is very small on x86_64, this makes larger SG_IO transfers
very eager to trigger OOM killer.  Fix it.  While at it, rename the
parameter to @dma_mask for clarity and convert comment to proper
winged style.

Signed-off-by: Tejun Heo 
Signed-off-by: Jens Axboe