Commit Graph

1151 Commits

Author SHA1 Message Date
Jens Axboe
464191c65b Revert "cfq: Make use of service count to estimate the rb_key offset"
This reverts commit 3586e917f2.

Corrado Zoccolo <czoccolo@gmail.com> correctly points out, that we need
consistency of rb_key offset across groups. This means we cannot properly
use the per-service_tree service count. Revert this change.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-30 09:38:13 +01:00
Corrado Zoccolo
8e550632cc cfq-iosched: fix corner cases in idling logic
Idling logic was disabled in some corner cases, leading to unfair share
 for noidle queues.
 * the idle timer was not armed if there were other requests in the
   driver. unfortunately, those requests could come from other workloads,
   or queues for which we don't enable idling. So we will check only
   pending requests from the active queue
 * rq_noidle check on no-idle queue could disable the end of tree idle if
   the last completed request was rq_noidle. Now, we will disable that
   idle only if all the queues served in the no-idle tree had rq_noidle
   requests.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 10:39:31 +01:00
Corrado Zoccolo
76280aff1c cfq-iosched: idling on deep seeky sync queues
Seeky sync queues with large depth can gain unfairly big share of disk
 time, at the expense of other seeky queues. This patch ensures that
 idling will be enabled for queues with I/O depth at least 4, and small
 think time. The decision to enable idling is sticky, until an idle
 window times out without seeing a new request.

The reasoning behind the decision is that, if an application is using
large I/O depth, it is already optimized to make full utilization of
the hardware, and therefore we reserve a slice of exclusive use for it.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 10:39:31 +01:00
Corrado Zoccolo
e4a229196a cfq-iosched: fix no-idle preemption logic
An incoming no-idle queue should preempt the active no-idle queue
 only if the active queue is idling due to service tree empty.
 Previous code was buggy in two ways:
 * it relied on service_tree field to be set on the active queue, while
   it is not set when the code is idling for a new request
 * it didn't check for the service tree empty condition, so could lead to
   LIFO behaviour if multiple queues with depth > 1 were preempting each
   other on an non-NCQ device.

Reported-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 10:39:31 +01:00
Corrado Zoccolo
e459dd08f4 cfq-iosched: fix ncq detection code
CFQ's detection of queueing devices initially assumes a queuing device
and detects if the queue depth reaches a certain threshold.
However, it will reconsider this choice periodically.

Unfortunately, if device is considered not queuing, CFQ will force a
unit queue depth for some workloads, thus defeating the detection logic.
This leads to poor performance on queuing hardware,
since the idle window remains enabled.

Given this premise, switching to hw_tag = 0 after we have proved at
least once that the device is NCQ capable is not a good choice.

The new detection code starts in an indeterminate state, in which CFQ behaves
as if hw_tag = 1, and then, if for a long observation period we never saw
large depth, we switch to hw_tag = 0, otherwise we stick to hw_tag = 1,
without reconsidering it again.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 10:02:57 +01:00
Corrado Zoccolo
c16632bab1 cfq-iosched: cleanup unreachable code
cfq_should_idle returns false for no-idle queues that are not the last,
so the control flow will never reach the removed code in a state that
satisfies the if condition.
The unreachable code was added to emulate previous cfq behaviour for
non-NCQ rotational devices. My tests show that even without it, the
performances and fairness are comparable with previous cfq, thanks to
the fact that all seeky queues are grouped together, and that we idle at
the end of the tree.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 09:46:46 +01:00
Ilya Loginov
2d4dc890b5 block: add helpers to run flush_dcache_page() against a bio and a request's pages
Mtdblock driver doesn't call flush_dcache_page for pages in request.  So,
this causes problems on architectures where the icache doesn't fill from
the dcache or with dcache aliases.  The patch fixes this.

The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid
pointless empty cache-thrashing loops on architectures for which
flush_dcache_page() is a no-op.  Every architecture was provided with this
flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is
equal 1 or do nothing otherwise.

See "fix mtd_blkdevs problem with caches on some architectures" discussion
on LKML for more information.

Signed-off-by: Ilya Loginov <isloginov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Peter Horton <phorton@bitbox.co.uk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 09:16:19 +01:00
Gui Jianfeng
3586e917f2 cfq: Make use of service count to estimate the rb_key offset
For the moment, different workload cfq queues are put into different
service trees. But CFQ still uses "busy_queues" to estimate rb_key
offset when inserting a cfq queue into a service tree. I think this
isn't appropriate, and it should make use of service tree count to do
this estimation. This patch is for for-2.6.33 branch.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-26 09:14:11 +01:00
Randy Dunlap
ad5ebd2fa2 block: jiffies fixes
Use HZ-independent calculation of milliseconds.
Add jiffies.h where it was missing since functions or macros
from it are used.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-11 13:47:45 +01:00
Martin K. Petersen
86b3728141 block: Expose discard granularity
While SSDs track block usage on a per-sector basis, RAID arrays often
have allocation blocks that are bigger.  Allow the discard granularity
and alignment to be set and teach the topology stacking logic how to
handle them.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-10 11:50:21 +01:00
Corrado Zoccolo
cf7c25cf91 cfq-iosched: fix next_rq computation
Cfq has a bug in computation of next_rq, that affects transition
between multiple sequential request streams in a single queue
(e.g.: two sequential buffered writers of the same priority),
causing the alternation between the two streams for a transient period.

  8,0    1    18737     0.260400660  5312  D   W 141653311 + 256
  8,0    1    20839     0.273239461  5400  D   W 141653567 + 256
  8,0    1    20841     0.276343885  5394  D   W 142803919 + 256
  8,0    1    20843     0.279490878  5394  D   W 141668927 + 256
  8,0    1    20845     0.292459993  5400  D   W 142804175 + 256
  8,0    1    20847     0.295537247  5400  D   W 141668671 + 256
  8,0    1    20849     0.298656337  5400  D   W 142804431 + 256
  8,0    1    20851     0.311481148  5394  D   W 141668415 + 256
  8,0    1    20853     0.314421305  5394  D   W 142804687 + 256
  8,0    1    20855     0.318960112  5400  D   W 142804943 + 256

The fix makes sure that the next_rq is computed from the last
dispatched request, and not affected by merging.

  8,0    1    37776     4.305161306     0  D   W 141738087 + 256
  8,0    1    37778     4.308298091     0  D   W 141738343 + 256
  8,0    1    37780     4.312885190     0  D   W 141738599 + 256
  8,0    1    37782     4.315933291     0  D   W 141738855 + 256
  8,0    1    37784     4.319064459     0  D   W 141739111 + 256
  8,0    1    37786     4.331918431  5672  D   W 142803007 + 256
  8,0    1    37788     4.334930332  5672  D   W 142803263 + 256
  8,0    1    37790     4.337902723  5672  D   W 142803519 + 256
  8,0    1    37792     4.342359774  5672  D   W 142803775 + 256
  8,0    1    37794     4.345318286     0  D   W 142804031 + 256

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-08 17:16:46 +01:00
H Hartley Sweeten
476d42f138 block/scsi_ioctl.c: quiet sparse noise
Quiet sparse noise about symbol's not being declared.

Symbol blk_default_cmd_filter is only used locally and should be static.

The function blk_scsi_ioctl_init() is a fs_initcall and should also be
static.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-04 09:10:33 +01:00
Jens Axboe
e00ef79971 cfq-iosched: get rid of the coop_preempt flag
We need to rework this logic post the cooperating cfq_queue merging,
for now just get rid of it and Jeff Moyer will fix the fall out.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-04 08:54:55 +01:00
Jens Axboe
125c4f221a cfq-iosched: fix merge error
We ended up with testing the same condition twice, pretty
pointless. Remove that first if.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-03 21:25:45 +01:00
Jens Axboe
2058297d2d Merge branch 'for-linus' into for-2.6.33
Conflicts:
	block/cfq-iosched.c

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-03 21:14:39 +01:00
Jens Axboe
150e6c67f4 Merge branch 'cfq-2.6.33' into for-2.6.33 2009-11-03 21:12:10 +01:00
Shaohua Li
4b27e1bb44 cfq-iosched: limit coop preemption
CFQ has an optimization for cooperated applications. if several
io-context have close requests, they will get boost. But the
optimization get abused. Considering thread a, b, which work on one
file. a reads sectors s, s+2, s+4, ...; b reads sectors s+1, s+3, s
+5, ... Both a and b are sequential read, so they can open idle window.
a reads a sector s and goes to idle window and wakeup b. b reads sector
s+1, since in current implementation, cfq_should_preempt() thinks a and
b are cooperators, b will preempt a. b then reads sector s+1 and goes to
idle window and wakeup a. for the same reason, a will preempt b and
reads s+2. a and b will continue the circle. The circle will be very
long, and a and b will occupy whole disk queue. Other applications will
nearly have no chance to run.

Fix this limiting coop preempt until a queue is scheduled normally
again.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-03 20:25:02 +01:00
Jens Axboe
e6ec4fe245 cfq-iosched: fix bad return value cfq_should_preempt()
Commit a6151c3a5c inadvertently reversed
a preempt condition check, potentially causing a performance regression.
Make the meta check correct again.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-03 20:21:35 +01:00
Corrado Zoccolo
dddb74519a cfq-iosched: simplify prio-unboost code
Eliminate redundant checks.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-11-02 10:40:37 +01:00
Jens Axboe
5869619cb5 cfq-iosched: fix style issue in cfq_get_avg_queues()
Line breaks and bad brace placement.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28 09:27:07 +01:00
Corrado Zoccolo
718eee0579 cfq-iosched: fairness for sync no-idle queues
Currently no-idle queues in cfq are not serviced fairly:
even if they can only dispatch a small number of requests at a time,
they have to compete with idling queues to be serviced, experiencing
large latencies.

We should notice, instead, that no-idle queues are the ones that would
benefit most from having low latency, in fact they are any of:
* processes with large think times (e.g. interactive ones like file
  managers)
* seeky (e.g. programs faulting in their code at startup)
* or marked as no-idle from upper levels, to improve latencies of those
  requests.

This patch improves the fairness and latency for those queues, by:
* separating sync idle, sync no-idle and async queues in separate
  service_trees, for each priority
* service all no-idle queues together
* and idling when the last no-idle queue has been serviced, to
  anticipate for more no-idle work
* the timeslices allotted for idle and no-idle service_trees are
  computed proportionally to the number of processes in each set.

Servicing all no-idle queues together should have a performance boost
for NCQ-capable drives, without compromising fairness.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28 09:23:26 +01:00
Corrado Zoccolo
a6d44e982d cfq-iosched: enable idling for last queue on priority class
cfq can disable idling for queues in various circumstances.
When workloads of different priorities are competing, if the higher
priority queue has idling disabled, lower priority queues may steal
its disk share. For example, in a scenario with an RT process
performing seeky reads vs a BE process performing sequential reads,
on an NCQ enabled hardware, with low_latency unset,
the RT process will dispatch only the few pending requests every full
slice of service for the BE process.

The patch solves this issue by always performing idle on the last
queue at a given priority class > idle. If the same process, or one
that can pre-empt it (so at the same priority or higher), submits a
new request within the idle window, the lower priority queue won't
dispatch, saving the disk bandwidth for higher priority ones.

Note: this doesn't touch the non_rotational + NCQ case (no hardware
to test if this is a benefit in that case).

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28 09:23:26 +01:00
Corrado Zoccolo
c0324a020e cfq-iosched: reimplement priorities using different service trees
We use different service trees for different priority classes.
This allows a simplification in the service tree insertion code, that no
longer has to consider priority while walking the tree.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28 09:23:26 +01:00
Corrado Zoccolo
aa6f6a3de1 cfq-iosched: preparation to handle multiple service trees
We embed a pointer to the service tree in each queue, to handle multiple
service trees easily.
Service trees are enriched with a counter.
cfq_add_rq_rb is invoked after putting the rq in the fifo, to ensure
that all fields in rq are properly initialized.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28 09:23:26 +01:00
Corrado Zoccolo
5db5d64277 cfq-iosched: adapt slice to number of processes doing I/O
When the number of processes performing I/O concurrently increases,
a fixed time slice per process will cause large latencies.

This patch, if low_latency mode is enabled,  will scale the time slice
assigned to each process according to a 300ms target latency.

In order to keep fairness among processes:
* The number of active processes is computed using a special form of
running average, that quickly follows sudden increases (to keep latency low),
and decrease slowly (to have fairness in spite of rapid decreases of this
value).

To safeguard sequential bandwidth, we impose a minimum time slice
(computed using 2*cfq_slice_idle as base, adjusted according to priority
and async-ness).

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-28 09:23:26 +01:00
Shaohua Li
1a1238a7dd cfq-iosched: improve hw_tag detection
If active queue hasn't enough requests and idle window opens, cfq will not
dispatch sufficient requests to hardware. In such situation, current code
will zero hw_tag. But this is because cfq doesn't dispatch enough requests
instead of hardware queue doesn't work. Don't zero hw_tag in such case.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-27 08:46:23 +01:00
Jeff Moyer
e6c5bc737a cfq: break apart merged cfqqs if they stop cooperating
cfq_queues are merged if they are issuing requests within the mean seek
distance of one another.  This patch detects when the coopearting stops and
breaks the queues back up.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26 14:34:47 +01:00
Jeff Moyer
b3b6d0408c cfq: change the meaning of the cfqq_coop flag
The flag used to indicate that a cfqq was allowed to jump ahead in the
scheduling order due to submitting a request close to the queue that
just executed.  Since closely cooperating queues are now merged, the flag
holds little meaning.  Change it to indicate that multiple queues were
merged.  This will later be used to allow the breaking up of merged queues
when they are no longer cooperating.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26 14:34:47 +01:00
Jeff Moyer
df5fe3e8e1 cfq: merge cooperating cfq_queues
When cooperating cfq_queues are detected currently, they are allowed to
skip ahead in the scheduling order.  It is much more efficient to
automatically share the cfq_queue data structure between cooperating processes.
Performance of the read-test2 benchmark (which is written to emulate the
dump(8) utility) went from 12MB/s to 90MB/s on my SATA disk.  NFS servers
with multiple nfsd threads also saw performance increases.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26 14:34:47 +01:00
Jeff Moyer
b2c18e1e08 cfq: calculate the seek_mean per cfq_queue not per cfq_io_context
async cfq_queue's are already shared between processes within the same
priority, and forthcoming patches will change the mapping of cic to sync
cfq_queue from 1:1 to 1:N.  So, calculate the seekiness of a process
based on the cfq_queue instead of the cfq_io_context.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-26 14:34:46 +01:00
Mark McLoughlin
6cafb12dc8 block: silently error unsupported empty barriers too
With 2.6.32-rc5 in a KVM guest using dm and virtio_blk, we see the
following errors:

  end_request: I/O error, dev vda, sector 0
  end_request: I/O error, dev vda, sector 0

The errors go away if dm stops submitting empty barriers, by reverting:

  commit 52b1fd5a27
  Author: Mikulas Patocka <mpatocka@redhat.com>
    dm: send empty barriers to targets in dm_flush

We should silently error all barriers, even empty barriers, on devices
like virtio_blk which don't support them.

See also:

  https://bugzilla.redhat.com/514901

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Neil Brown <neilb@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-24 14:14:31 +02:00
Jens Axboe
c30f33437c Merge branch 'for-linus' into for-2.6.33 2009-10-13 12:29:45 +02:00
Randy Dunlap
c7ebf0657b blk-settings: fix function parameter kernel-doc notation
Fix kernel-doc notation in blk-settings.c::blk_queue_max_discard_sectors().

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-12 08:20:47 +02:00
KOSAKI Motohiro
8c27959858 elv_iosched_store(): fix strstrip() misuse
elv_iosched_store() ignore the return value of strstrip().  It makes small
inconsistent behavior.

This patch fixes it.

 <before>
 ====================================
 # cd /sys/block/{blockdev}/queue

 case1:
 # echo "anticipatory" > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case2:
 # echo "anticipatory " > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case3:
 # echo " anticipatory" > scheduler
 bash: echo: write error: Invalid argument

 <after>
 ====================================
 # cd /sys/block/{blockdev}/queue

 case1:
 # echo "anticipatory" > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case2:
 # echo "anticipatory " > scheduler
 # cat scheduler
 noop [anticipatory] deadline cfq

 case3:
 # echo " anticipatory" > scheduler
 noop [anticipatory] deadline cfq

Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-09 08:48:08 +02:00
Corrado Zoccolo
355b659c87 cfq-iosched: avoid probable slice overrun when idling
If the average think time is larger than the remaining time slice
for any given queue, don't allow it to idle. A succesful idle also
means that we need to dispatch and complete a request, so if we don't
even have time left for the idle process, we would overrun the slice
in any case.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-08 08:43:32 +02:00
Jens Axboe
a6151c3a5c cfq-iosched: apply bool value where we return 0/1
Saves 16 bytes of text, woohoo. But the more important point is
that it makes the code more readable when returning bool for 0/1
cases.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-07 20:02:57 +02:00
Corrado Zoccolo
ec60e4f674 cfq-iosched: fix think time allowed for seekers
CFQ enables idle only for processes that think less than the allowed
idle time. Since idle time is lower for seeky queues, we should use the
correct value in the comparison.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-07 19:51:54 +02:00
Jens Axboe
b9c8946b19 cfq-iosched: fix the slice residual sign
We should subtract the slice residual from the rb tree key, since
a negative residual count indicates that the cfqq overran its slice
the last time. Hence we want to add the overrun time, to position
it a bit further away in the service tree.

Reported-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06 21:09:32 +02:00
Jens Axboe
0b182d617e cfq-iosched: abstract out the 'may this cfqq dispatch' logic
Makes the whole thing easier to read, cfq_dispatch_requests() was
a bit messy before.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06 20:49:37 +02:00
Jens Axboe
1b59dd511b block: use proper BLK_RW_ASYNC in blk_queue_start_tag()
Makes it easier to read than the 0.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06 20:19:02 +02:00
Nikanth Karthikesan
316d315bff block: Seperate read and write statistics of in_flight requests v2
Commit a9327cac44 added seperate read
and write statistics of in_flight requests. And exported the number
of read and write requests in progress seperately through sysfs.

But  Corrado Zoccolo <czoccolo@gmail.com> reported getting strange
output from "iostat -kx 2". Global values for service time and
utilization were garbage. For interval values, utilization was always
100%, and service time is higher than normal.

So this was reverted by commit 0f78ab9899

The problem was in part_round_stats_single(), I missed the following:
        if (now == part->stamp)
                return;

-       if (part->in_flight) {
+       if (part_in_flight(part)) {
                __part_stat_add(cpu, part, time_in_queue,
                                part_in_flight(part) * (now - part->stamp));
                __part_stat_add(cpu, part, io_ticks, (now - part->stamp));

With this chunk included, the reported regression gets fixed.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>

--
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-06 20:16:55 +02:00
Jens Axboe
23e018a1b0 block: get rid of kblock_schedule_delayed_work()
It was briefly introduced to allow CFQ to to delayed scheduling,
but we ended up removing that feature again. So lets kill the
function and export, and just switch CFQ back to the normal work
schedule since it is now passing in a '0' delay from all call
sites.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05 11:03:58 +02:00
Corrado Zoccolo
48e025e63a cfq-iosched: fix possible problem with jiffies wraparound
The RR service tree is indexed by a key that is relative to current jiffies.
This can cause problems on jiffies wraparound.

The patch fixes it using time_before comparison, and changing
the add_front path to use a relative number, too.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05 11:03:55 +02:00
Jens Axboe
30996f40bf cfq-iosched: fix issue with rq-rq merging and fifo list ordering
cfq uses rq->start_time as the fifo indicator, but that field may
get modified prior to cfq doing it's fifo list adjustment when
a request gets merged with another request. This can cause the
fifo list to become unordered.

Reported-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-05 11:03:39 +02:00
Jens Axboe
5d13379a4d Merge branch 'master' into for-2.6.33 2009-10-05 09:30:10 +02:00
Jens Axboe
0f78ab9899 Revert "Seperate read and write statistics of in_flight requests"
This reverts commit a9327cac44.

Corrado Zoccolo <czoccolo@gmail.com> reports:

"with 2.6.32-rc1 I started getting the following strange output from
"iostat -kx 2":
Linux 2.6.31bisect (et2) 	04/10/2009 	_i686_	(2 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          10,70    0,00    3,16   15,75    0,00   70,38

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda              18,22     0,00    0,67    0,01    14,77     0,02
43,94     0,01   10,53 39043915,03 2629219,87
sdb              60,89     9,68   50,79    3,04  1724,43    50,52
65,95     0,70   13,06 488437,47 2629219,87

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           2,72    0,00    0,74    0,00    0,00   96,53

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00
sdb               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           6,68    0,00    0,99    0,00    0,00   92,33

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00
sdb               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           4,40    0,00    0,73    1,47    0,00   93,40

Device:         rrqm/s   wrqm/s     r/s     w/s    rkB/s    wkB/s
avgrq-sz avgqu-sz   await  svctm  %util
sda               0,00     0,00    0,00    0,00     0,00     0,00
0,00     0,00    0,00   0,00 100,00
sdb               0,00     4,00    0,00    3,00     0,00    28,00
18,67     0,06   19,50 333,33 100,00

Global values for service time and utilization are garbage. For
interval values, utilization is always 100%, and service time is
higher than normal.

I bisected it down to:
[a9327cac44] Seperate read and write
statistics of in_flight requests
and verified that reverting just that commit indeed solves the issue
on 2.6.32-rc1."

So until this is debugged, revert the bad commit.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-04 21:04:38 +02:00
Jens Axboe
e00c54c36a cfq-iosched: don't delay async queue if it hasn't dispatched at all
We cannot delay for the first dispatch of the async queue if it
hasn't dispatched at all, since that could present a local user
DoS attack vector using an app that just did slow timed sync reads
while filling memory.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-04 20:36:19 +02:00
Martin K. Petersen
ac481c20ef block: Topology ioctls
Not all users of the topology information want to use libblkid.  Provide
the topology information through bdev ioctls.

Also clarify sector size comments for existing BLK ioctls.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 20:52:01 +02:00
Jens Axboe
61f0c1dcaa cfq-iosched: use assigned slice sync value, not default
We should use the sysfs modified slice sync value, in case it differs
from the default.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 19:46:03 +02:00
Jens Axboe
963b72fc66 cfq-iosched: rename 'desktop' sysfs entry to 'low_latency'
Don't think that's necessarily a perfect description of what this
option fiddles with, but it's probably better than 'desktop'.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 19:42:18 +02:00
Jens Axboe
8e29675555 cfq-iosched: implement slower async initiate and queue ramp up
This slowly ramps up the async queue depth based on the time
passed since the sync IO, and doesn't allow async at all until
a sync slice period has passed.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 16:27:13 +02:00
Vivek Goyal
365722bb91 cfq-iosched: delay async IO dispatch, if sync IO was just done
o Do not allow more than max_dispatch requests from an async queue, if some
  sync request has finished recently. This is in the hope that sync activity
  is still going on in the system and we might receive a sync request soon.
  Most likely from a sync queue which finished a request and we did not enable
  idling on it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 15:21:27 +02:00
Jens Axboe
08dc8726d4 block: CFQ is more than a desktop scheduler
Update Kconfig.iosched entry.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 09:40:47 +02:00
Jens Axboe
492af6350a block: remove the anticipatory IO scheduler
AS is mostly a subset of CFQ, so there's little point in still
providing this separate IO scheduler. Hopefully at some point we
can get down to one single IO scheduler again, at least this brings
us closer by having only one intelligent IO scheduler.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-03 09:37:51 +02:00
Jens Axboe
1d2235152d cfq-iosched: add a knob for desktop interactiveness
This is basically identical to what Vivek Goyal posted, but combined
into one and labelled 'desktop' instead of 'fairness'. The goal
is to continue to improve on the latency side of things as it relates
to interactiveness, keeping the questionable bits under this sysfs
tunable so it would be easy for throughput-only people to turn off.

Apart from adding the interactive sysfs knob, it also adds the
behavioural change of allowing slice idling even if the hardware
does tagged command queuing.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-02 20:06:02 +02:00
Jun'ichi Nomura
b0da3f0dad Add a tracepoint for block request remapping
Since 2.6.31 now has request-based device-mapper, it's useful to have
a tracepoint for request-remapping as well as bio-remapping.
This patch adds a tracepoint for request-remapping, trace_block_rq_remap().

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:19:34 +02:00
Christoph Hellwig
67efc92580 block: allow large discard requests
Currently we set the bio size to the byte equivalent of the blocks to
be trimmed when submitting the initial DISCARD ioctl.  That means it
is subject to the max_hw_sectors limitation of the HBA which is
much lower than the size of a DISCARD request we can support.
Add a separate max_discard_sectors tunable to limit the size for discard
requests.

We limit the max discard request size in bytes to 32bit as that is the
limit for bio->bi_size.  This could be much larger if we had a way to pass
that information through the block layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:19:34 +02:00
Christoph Hellwig
c15227de13 block: use normal I/O path for discard requests
prepare_discard_fn() was being called in a place where memory allocation
was effectively impossible.  This makes it inappropriate for all but
the most trivial translations of Linux's DISCARD operation to the block
command set.  Additionally adding a payload there makes the ownership
of the bio backing unclear as it's now allocated by the device driver
and not the submitter as usual.

It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
the queue supports discard operations or not.  blkdev_issue_discard now
allocates a one-page, sector-length payload which is the right thing
for the common ATA and SCSI implementations.

The mtd implementation of prepare_discard_fn() is replaced with simply
checking for the request being a discard.

Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:19:30 +02:00
Jun'ichi Nomura
1a35e0f644 Add a tracepoint for block request remapping
Since 2.6.31 now has request-based device-mapper, it's useful to have
a tracepoint for request-remapping as well as bio-remapping.
This patch adds a tracepoint for request-remapping, trace_block_rq_remap().

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Alasdair G Kergon <agk@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:16:13 +02:00
Christoph Hellwig
ca80650cfb block: allow large discard requests
Currently we set the bio size to the byte equivalent of the blocks to
be trimmed when submitting the initial DISCARD ioctl.  That means it
is subject to the max_hw_sectors limitation of the HBA which is
much lower than the size of a DISCARD request we can support.
Add a separate max_discard_sectors tunable to limit the size for discard
requests.

We limit the max discard request size in bytes to 32bit as that is the
limit for bio->bi_size.  This could be much larger if we had a way to pass
that information through the block layer.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:15:46 +02:00
Christoph Hellwig
1122a26f2a block: use normal I/O path for discard requests
prepare_discard_fn() was being called in a place where memory allocation
was effectively impossible.  This makes it inappropriate for all but
the most trivial translations of Linux's DISCARD operation to the block
command set.  Additionally adding a payload there makes the ownership
of the bio backing unclear as it's now allocated by the device driver
and not the submitter as usual.

It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
the queue supports discard operations or not.  blkdev_issue_discard now
allocates a one-page, sector-length payload which is the right thing
for the common ATA and SCSI implementations.

The mtd implementation of prepare_discard_fn() is replaced with simply
checking for the request being a discard.

Largely based on a previous patch from Matthew Wilcox <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.

Signed-off-by: Christoph Hellwig <hch@lst.de>
2009-10-01 21:15:46 +02:00
Zdenek Kabelac
48c0d4d4c0 Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs
Add missing blk_trace_remove_sysfs to be in pair with blk_trace_init_sysfs
introduced in commit 1d54ad6da9.
Release kobject also in case the request_fn is NULL.

Problem was noticed via kmemleak backtrace when some sysfs entries were
note properly destroyed during  device removal:

unreferenced object 0xffff88001aa76640 (size 80):
  comm "lvcreate", pid 2120, jiffies 4294885144
  hex dump (first 32 bytes):
    01 00 00 00 00 00 00 00 f0 65 a7 1a 00 88 ff ff  .........e......
    90 66 a7 1a 00 88 ff ff 86 1d 53 81 ff ff ff ff  .f........S.....
  backtrace:
    [<ffffffff813f9cc6>] kmemleak_alloc+0x26/0x60
    [<ffffffff8111d693>] kmem_cache_alloc+0x133/0x1c0
    [<ffffffff81195891>] sysfs_new_dirent+0x41/0x120
    [<ffffffff81194b0c>] sysfs_add_file_mode+0x3c/0xb0
    [<ffffffff81197c81>] internal_create_group+0xc1/0x1a0
    [<ffffffff81197d93>] sysfs_create_group+0x13/0x20
    [<ffffffff810d8004>] blk_trace_init_sysfs+0x14/0x20
    [<ffffffff8123f45c>] blk_register_queue+0x3c/0xf0
    [<ffffffff812447e4>] add_disk+0x94/0x160
    [<ffffffffa00d8b08>] dm_create+0x598/0x6e0 [dm_mod]
    [<ffffffffa00de951>] dev_create+0x51/0x350 [dm_mod]
    [<ffffffffa00de823>] ctl_ioctl+0x1a3/0x240 [dm_mod]
    [<ffffffffa00de8f2>] dm_compat_ctl_ioctl+0x12/0x20 [dm_mod]
    [<ffffffff81177bfd>] compat_sys_ioctl+0xcd/0x4f0
    [<ffffffff81036ed8>] sysenter_dispatch+0x7/0x2c
    [<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Zdenek Kabelac <zkabelac@redhat.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:15:46 +02:00
Martin K. Petersen
5dee2477df block: Do not clamp max_hw_sectors for stacking devices
Stacking devices do not have an inherent max_hw_sector limit.  Set the
default to INT_MAX so we are bounded only by capabilities of the
underlying storage.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:15:45 +02:00
Martin K. Petersen
80ddf247c8 block: Set max_sectors correctly for stacking devices
The topology changes unintentionally caused SAFE_MAX_SECTORS to be set
for stacking devices.  Set the default limit to BLK_DEF_MAX_SECTORS and
provide SAFE_MAX_SECTORS in blk_queue_make_request() for legacy hw
drivers that depend on the old behavior.

Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-10-01 21:15:45 +02:00
Kay Sievers
e454cea20b Driver-Core: extend devnode callbacks to provide permissions
This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.

This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-19 12:50:38 -07:00
Linus Torvalds
ab86e5765d Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6:
  Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev
  debugfs: Modify default debugfs directory for debugging pktcdvd.
  debugfs: Modified default dir of debugfs for debugging UHCI.
  debugfs: Change debugfs directory of IWMC3200
  debugfs: Change debuhgfs directory of trace-events-sample.h
  debugfs: Fix mount directory of debugfs by default in events.txt
  hpilo: add poll f_op
  hpilo: add interrupt handler
  hpilo: staging for interrupt handling
  driver core: platform_device_add_data(): use kmemdup()
  Driver core: Add support for compatibility classes
  uio: add generic driver for PCI 2.3 devices
  driver-core: move dma-coherent.c from kernel to driver/base
  mem_class: fix bug
  mem_class: use minor as index instead of searching the array
  driver model: constify attribute groups
  UIO: remove 'default n' from Kconfig
  Driver core: Add accessor for device platform data
  Driver core: move dev_get/set_drvdata to drivers/base/dd.c
  Driver core: add new device to bus's list before probing
2009-09-16 08:27:10 -07:00
David Brownell
a4dbd6740d driver model: constify attribute groups
Let attribute group vectors be declared "const".  We'd
like to let most attribute metadata live in read-only
sections... this is a start.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-09-15 09:50:47 -07:00
Linus Torvalds
ada3fa1505 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (46 commits)
  powerpc64: convert to dynamic percpu allocator
  sparc64: use embedding percpu first chunk allocator
  percpu: kill lpage first chunk allocator
  x86,percpu: use embedding for 64bit NUMA and page for 32bit NUMA
  percpu: update embedding first chunk allocator to handle sparse units
  percpu: use group information to allocate vmap areas sparsely
  vmalloc: implement pcpu_get_vm_areas()
  vmalloc: separate out insert_vmalloc_vm()
  percpu: add chunk->base_addr
  percpu: add pcpu_unit_offsets[]
  percpu: introduce pcpu_alloc_info and pcpu_group_info
  percpu: move pcpu_lpage_build_unit_map() and pcpul_lpage_dump_cfg() upward
  percpu: add @align to pcpu_fc_alloc_fn_t
  percpu: make @dyn_size mandatory for pcpu_setup_first_chunk()
  percpu: drop @static_size from first chunk allocators
  percpu: generalize first chunk allocator selection
  percpu: build first chunk allocators selectively
  percpu: rename 4k first chunk allocator to page
  percpu: improve boot messages
  percpu: fix pcpu_reclaim() locking
  ...

Fix trivial conflict as by Tejun Heo in kernel/sched.c
2009-09-15 09:39:44 -07:00
Linus Torvalds
355bbd8cb8 Merge branch 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.32' of git://git.kernel.dk/linux-2.6-block: (29 commits)
  block: use blkdev_issue_discard in blk_ioctl_discard
  Make DISCARD_BARRIER and DISCARD_NOBARRIER writes instead of reads
  block: don't assume device has a request list backing in nr_requests store
  block: Optimal I/O limit wrapper
  cfq: choose a new next_req when a request is dispatched
  Seperate read and write statistics of in_flight requests
  aoe: end barrier bios with EOPNOTSUPP
  block: trace bio queueing trial only when it occurs
  block: enable rq CPU completion affinity by default
  cfq: fix the log message after dispatched a request
  block: use printk_once
  cciss: memory leak in cciss_init_one()
  splice: update mtime and atime on files
  block: make blk_iopoll_prep_sched() follow normal 0/1 return convention
  cfq-iosched: get rid of must_alloc flag
  block: use interrupts disabled version of raise_softirq_irqoff()
  block: fix comment in blk-iopoll.c
  block: adjust default budget for blk-iopoll
  block: fix long lines in block/blk-iopoll.c
  block: add blk-iopoll, a NAPI like approach for block devices
  ...
2009-09-14 17:55:15 -07:00
Christoph Hellwig
746cd1e7e4 block: use blkdev_issue_discard in blk_ioctl_discard
blk_ioctl_discard duplicates large amounts of code from blkdev_issue_discard,
the only difference between the two is that blkdev_issue_discard needs to
send a barrier discard request and blk_ioctl_discard a non-barrier one,
and blk_ioctl_discard needs to wait on the request.  To facilitates this
add a flags argument to blkdev_issue_discard to control both aspects of the
behaviour.  This will be very useful later on for using the waiting
funcitonality for other callers.

Based on an earlier patch from Matthew Wilcox <matthew@wil.cx>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:53 +02:00
Jens Axboe
b8a9ae779f block: don't assume device has a request list backing in nr_requests store
Stacked devices do not. For now, just error out with -EINVAL. Later
we could make the limit apply on stacked devices too, for throttling
reasons.

This fixes

5a54cd13353bb3b88887604e2c980aa01e314309

and should go into 2.6.31 stable as well.

Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:53 +02:00
Martin K. Petersen
3c5820c743 block: Optimal I/O limit wrapper
Implement blk_limits_io_opt() and make blk_queue_io_opt() a wrapper
around it. DM needs this to avoid poking at the queue_limits directly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:52 +02:00
Jeff Moyer
06d2188644 cfq: choose a new next_req when a request is dispatched
This patch addresses http://bugzilla.kernel.org/show_bug.cgi?id=13401, a
regression introduced in 2.6.30.

From the bug report:

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:52 +02:00
Nikanth Karthikesan
a9327cac44 Seperate read and write statistics of in_flight requests
Currently, there is a single in_flight counter measuring the number of
requests in the request_queue. But some monitoring tools would like to
know how many read requests and write requests are in progress. Split the
current in_flight counter into two seperate counters for read and write.

This information is exported as a sysfs attribute, as changing the
currently available stat files would break the existing tools.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:52 +02:00
Minchan Kim
01edede41e block: trace bio queueing trial only when it occurs
If BIO is discarded or cross over end of device,
BIO queueing trial doesn't occur.

Actually the trace was called just before make_request at first:
[PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23
      2056a782f8e7e65fd4bfd027506b4ce1c5e9ccd4

And then 2 patches added some checks between them:
[PATCH] md: check bio address after mapping through partitions
        5ddfe9691c91a244e8d1be597b6428fcefd58103,
[BLOCK] Don't allow empty barriers to be passed down to
queues that don't grok them
        51fd77bd9f512ab6cc9df0733ba1caaab89eb957

It breaks original goal.
Let's trace it only when it happens.

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:34:34 +02:00
Shan Wei
b217a903ab cfq: fix the log message after dispatched a request
The blktrace tools can show process id when cfq dispatched a request,
using cfq_log_cfqq() instead of cfq_log().

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:34:33 +02:00
Jens Axboe
1b379d8daf cfq-iosched: get rid of must_alloc flag
It's not currently used, as pointed out by
Gui Jianfeng <guijianfeng@cn.fujitsu.com>. We already check the
wait_request flag to allow an idling queue priority allocation access,
so we don't need this extra flag.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:32 +02:00
Jens Axboe
a33dac26d4 block: use interrupts disabled version of raise_softirq_irqoff()
We already have interrupts disabled at that point, so use the
__raise_softirq_irqoff() variant.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:32 +02:00
Jens Axboe
fca51d64c5 block: fix comment in blk-iopoll.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:32 +02:00
Jens Axboe
37867ae7c5 block: adjust default budget for blk-iopoll
It's not exported, I doubt we'll have a reason to change this...

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Jens Axboe
1badcfbd7f block: fix long lines in block/blk-iopoll.c
Note sure why they happened in the first place, probably some bad
terminal setting.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Jens Axboe
5e605b64a1 block: add blk-iopoll, a NAPI like approach for block devices
This borrows some code from NAPI and implements a polled completion
mode for block devices. The idea is the same as NAPI - instead of
doing the command completion when the irq occurs, schedule a dedicated
softirq in the hopes that we will complete more IO when the iopoll
handler is invoked. Devices have a budget of commands assigned, and will
stay in polled mode as long as they continue to consume their budget
from the iopoll softirq handler. If they do not, the device is set back
to interrupt completion mode.

This patch holds the core bits for blk-iopoll, device driver support
sold separately.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Jens Axboe
fb1e75389b block: improve queue_should_plug() by looking at IO depths
Instead of just checking whether this device uses block layer
tagging, we can improve the detection by looking at the maximum
queue depth it has reached. If that crosses 4, then deem it a
queuing device.

This is important on high IOPS devices, since plugging hurts
the performance there (it can be as much as 10-15% of the sys
time).

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Jens Axboe
1f98a13f62 bio: first step in sanitizing the bio->bi_rw flag testing
Get rid of any functions that test for these bits and make callers
use bio_rw_flagged() directly. Then it is at least directly apparent
what variable and flag they check.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Hannes Reinecke
e3264a4d7d Send uevents for write_protect changes
Whenever a block device changes it's read-only attribute
notify the userspace about it.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Vivek Goyal
d58b85e1e8 cfq-iosched: no need to keep track of busy_rt_queues
o Get rid of busy_rt_queues infrastructure. Looks like it is redundant.

o Once an RT queue gets request it will preempt any of the BE or IDLE queues
  immediately. Otherwise this queue will be put on service tree and scheduler
  will anyway select this queue before any of the BE or IDLE queue. Hence
  looks like there is no need to keep track of how many busy RT queues are
  currently on service tree.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:30 +02:00
Jens Axboe
5ad531db6e cfq-iosched: drain device queue before switching to a sync queue
To lessen the impact of async IO on sync IO, let the device drain of
any async IO in progress when switching to a sync cfqq that has idling
enabled.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:30 +02:00
Tejun Heo
da6c5c720c scsi,block: update SCSI to handle mixed merge failures
Update scsi_io_completion() such that it only fails requests till the
next error boundary and retry the leftover.  This enables block layer
to merge requests with different failfast settings and still behave
correctly on errors.  Allow merge of requests of different failfast
settings.

As SCSI is currently the only subsystem which follows failfast status,
there's no need to worry about other block drivers for now.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Niel Lambrechts <niel.lambrechts@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:30 +02:00
Tejun Heo
80a761fd33 block: implement mixed merge of different failfast requests
Failfast has characteristics from other attributes.  When issuing,
executing and successuflly completing requests, failfast doesn't make
any difference.  It only affects how a request is handled on failure.
Allowing requests with different failfast settings to be merged cause
normal IOs to fail prematurely while not allowing has performance
penalties as failfast is used for read aheads which are likely to be
located near in-flight or to-be-issued normal IOs.

This patch introduces the concept of 'mixed merge'.  A request is a
mixed merge if it is merge of segments which require different
handling on failure.  Currently the only mixable attributes are
failfast ones (or lack thereof).

When a bio with different failfast settings is added to an existing
request or requests of different failfast settings are merged, the
merged request is marked mixed.  Each bio carries failfast settings
and the request always tracks failfast state of the first bio.  When
the request fails, blk_rq_err_bytes() can be used to determine how
many bytes can be safely failed without crossing into an area which
requires further retrials.

This allows request merging regardless of failfast settings while
keeping the failure handling correct.

This patch only implements mixed merge but doesn't enable it.  The
next one will update SCSI to make use of mixed merge.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Niel Lambrechts <niel.lambrechts@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:30 +02:00
Tejun Heo
a82afdfcb8 block: use the same failfast bits for bio and request
bio and request use the same set of failfast bits.  This patch makes
the following changes to simplify things.

* enumify BIO_RW* bits and reorder bits such that BIOS_RW_FAILFAST_*
  bits coincide with __REQ_FAILFAST_* bits.

* The above pushes BIO_RW_AHEAD out of sync with __REQ_FAILFAST_DEV
  but the matching is useless anyway.  init_request_from_bio() is
  responsible for setting FAILFAST bits on FS requests and non-FS
  requests never use BIO_RW_AHEAD.  Drop the code and comment from
  blk_rq_bio_prep().

* Define REQ_FAILFAST_MASK which is OR of all FAILFAST bits and
  simplify FAILFAST flags handling in init_request_from_bio().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:27 +02:00
Jens Axboe
d993831fa7 writeback: add name to backing_dev_info
This enables us to track who does what and print info. Its main use
is catching dirty inodes on the default_backing_dev_info, so we can
fix that up.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 09:20:26 +02:00
Nikanth Karthikesan
c295fc0578 block: Allow changing max_sectors_kb above the default 512
The patch "block: Use accessor functions for queue limits"
(ae03bf639a) changed queue_max_sectors_store()
to use blk_queue_max_sectors() instead of directly assigning the value.

But blk_queue_max_sectors() differs a bit
1. It sets both max_sectors_kb, and max_hw_sectors_kb
2. Never allows one to change max_sectors_kb above BLK_DEF_MAX_SECTORS. If one
specifies a value greater then max_hw_sectors is set to that value but
max_sectors is set to BLK_DEF_MAX_SECTORS

I am not sure whether blk_queue_max_sectors() should be changed, as it seems
to be that way for a long time. And there may be callers dependent on that
behaviour.

This patch simply reverts to the older way of directly assigning the value to
max_sectors as it was before.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-01 22:40:15 +02:00
Tejun Heo
384be2b18a Merge branch 'percpu-for-linus' into percpu-for-next
Conflicts:
	arch/sparc/kernel/smp_64.c
	arch/x86/kernel/cpu/perf_counter.c
	arch/x86/kernel/setup_percpu.c
	drivers/cpufreq/cpufreq_ondemand.c
	mm/percpu.c

Conflicts in core and arch percpu codes are mostly from commit
ed78e1e078dd44249f88b1dd8c76dafb39567161 which substituted many
num_possible_cpus() with nr_cpu_ids.  As for-next branch has moved all
the first chunk allocators into mm/percpu.c, the changes are moved
from arch code to mm/percpu.c.

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-08-14 14:45:31 +09:00
John Stoffel
14d9fa3525 Make SCSI SG v4 driver enabled by default and remove EXPERIMENTAL dependency, since udev depends on BSG
Make Block Layer SG support v4 the default, since recent udev versions
depend on this to access serial numbers and other low level info properly.

This should be backported to older kernels as well, since most distros have
enabled this for a long time.

Signed-off-by: John Stoffel <john@stoffel.org>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-04 22:10:17 +02:00
Martin K. Petersen
7e5f5fb09e block: Update topology documentation
Update topology comments and sysfs documentation based upon discussions
with Neil Brown.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-01 10:24:35 +02:00
Martin K. Petersen
70dd5bf3b9 block: Stack optimal I/O size
When stacking block devices ensure that optimal I/O size is scaled
accordingly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-01 10:24:35 +02:00
Martin K. Petersen
7c958e3264 block: Add a wrapper for setting minimum request size without a queue
Introduce blk_limits_io_min() and make blk_queue_io_min() call it.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-01 10:24:35 +02:00
Martin K. Petersen
fef246672b block: Make blk_queue_stack_limits use the new stacking interface
blk_queue_stack_limits() has been superceded by blk_stack_limits() and
disk_stack_limits().  Wrap the function call for now, we'll deprecate it
later.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-01 10:24:35 +02:00
Jens Axboe
56ad1740d9 block: make the end_io functions be non-GPL exports
Prior to the change for more sane end_io functions, we exported
the helpers with the normal EXPORT_SYMBOL(). That got changed
to _GPL() for the new interface. Revert that particular change,
on the basis that this is basic functionality and doesn't dip
into internal structures. If these exports can't be non-GPL,
then we may as well make EXPORT_SYMBOL() imply GPL for
everything.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-28 22:11:24 +02:00
Xiaotian Feng
3839e4b29b block: fix improper kobject release in blk_integrity_unregister
blk_integrity_unregister should use kobject_put to release the kobject,
otherwise after bi is freed, memory of bi->kobj->name is leaked.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-28 09:11:14 +02:00
Jens Axboe
a4e7d46407 block: always assign default lock to queues
Move the assignment of a default lock below blk_init_queue() to
blk_queue_make_request(), so we also get to set the default lock
for ->make_request_fn() based drivers. This is important since the
queue flag locking requires a lock to be in place.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-28 09:07:29 +02:00
Xiaotian Feng
9cb308ce8d block: sysfs fix mismatched queue_var_{store,show} in 64bit kernel
In blk-sysfs.c, queue_var_store uses unsigned long to store data,
but queue_var_show uses unsigned int to show data.  This causes,

	# echo 70000000000 > /sys/block/<dev>/queue/read_ahead_kb
	# cat /sys/block/<dev>/queue/read_ahead_kb => get wrong value

Fix it by using unsigned long.

While at it, convert queue_rq_affinity_show() such that it uses bool
variable instead of explicit != 0 testing.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2009-07-17 16:54:15 +09:00
Tejun Heo
0a09f4319c block: fix failfast merge testing in elv_rq_merge_ok()
Commit ab0fd1debe tries to prevent merge
of requests with different failfast settings.  In elv_rq_merge_ok(),
it compares new bio's failfast flags against the merge target
request's.  However, the flag testing accessors for bio and blk don't
return boolean but the tested bit value directly and FAILFAST on bio
and blk don't match, so directly comparing them with == results in
false negative unnecessary preventing merge of readahead requests.

This patch convert the results to boolean by negating them before
comparison.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jeff Garzik <jeff@garzik.org>
2009-07-17 14:50:43 +09:00
Vivek Goyal
32f2e807a3 cfq-iosched: reset oom_cfqq in cfq_set_request()
In case memory is scarce, we now default to oom_cfqq. Once memory is
available again, we should allocate a new cfqq and stop using oom_cfqq for
a particular io context.

Once a new request comes in, check if we are using oom_cfqq, and if yes,
try to allocate a new cfqq.

Tested the patch by forcing the use of oom_cfqq and upon next request thread
realized that it was using oom_cfqq and it allocated a new cfqq.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-10 20:31:54 +02:00
FUJITA Tomonori
76da03467a block: call blk_scsi_ioctl_init()
Currently, blk_scsi_ioctl_init() is not called since it lacks
an initcall marking. This causes the command table to be
unitialized, hence somce commands are block when they should
not have been.

This fixes a regression introduced by commit
018e044689

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-10 20:31:53 +02:00
Tejun Heo
c43768cbb7 Merge branch 'master' into for-next
Pull linus#master to merge PER_CPU_DEF_ATTRIBUTES and alpha build fix
changes.  As alpha in percpu tree uses 'weak' attribute instead of
inline assembly, there's no need for __used attribute.

Conflicts:
	arch/alpha/include/asm/percpu.h
	arch/mn10300/kernel/vmlinux.lds.S
	include/linux/percpu-defs.h
2009-07-04 07:13:18 +09:00
Tejun Heo
ab0fd1debe block: don't merge requests of different failfast settings
Block layer used to merge requests and bios with different failfast
settings.  This caused regular IOs to fail prematurely when they were
merged into failfast requests for readahead.

Niel Lambrechts could trigger the problem semi-reliably on ext4 when
resuming from STR.  ext4 uses readahead when reading inodes and
combined with the deterministic extra SATA PHY exception cycle during
resume on the specific configuration, non-readahead inode read would
fail causing ext4 errors.  Please read the following thread for
details.

  http://lkml.org/lkml/2009/5/23/21

This patch makes block layer reject merging if the failfast settings
don't match.  This is correct but likely to lower IO performance by
preventing regular IOs from mingling into surrounding readahead
requests.  Changes to allow such mixed merges and handle errors
correctly will be added later.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Niel Lambrechts <niel.lambrechts@gmail.com>
Cc: Theodore Tso <tytso@mit.edu>
Signed-off-by: Jens Axboe <axboe@carl.(none)>
2009-07-03 21:06:45 +02:00
Shan Wei
b706f64281 cfq-iosched: remove redundant check for NULL cfqq in cfq_set_request()
With the changes for falling back to an oom_cfqq, we never fail
to find/allocate a queue in cfq_get_queue(). So remove the check.

Signed-off-by: Shan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-01 12:41:14 +02:00
NeilBrown
db64f680ba blocK: Restore barrier support for md and probably other virtual devices.
The next_ordered flag is only meaningful for devices that use __make_request.
So move the test against next_ordered out of generic code and in to
__make_request

Since this test was added, barriers have not worked on md or any
devices that don't use __make_request and so don't bother to set
next_ordered.  (dm explicitly sets something other than
QUEUE_ORDERED_NONE since
  commit 99360b4c18
but notes in the comments that it is otherwise meaningless).

Cc: Ken Milmore <ken.milmore@googlemail.com>
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-01 10:56:26 +02:00
Jens Axboe
018e044689 block: get rid of queue-private command filter
The initial patches to support this through sysfs export were broken
and have been if 0'ed out in any release. So lets just kill the code
and reclaim some space in struct request_queue, if anyone would later
like to fixup the sysfs bits, the git history can easily restore
the removed bits.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-01 10:56:26 +02:00
Martin K. Petersen
7878cba9f0 block: Create bip slabs with embedded integrity vectors
This patch restores stacking ability to the block layer integrity
infrastructure by creating a set of dedicated bip slabs.  Each bip slab
has an embedded bio_vec array at the end.  This cuts down on memory
allocations and also simplifies the code compared to the original bvec
version.  Only the largest bip slab is backed by a mempool.  The pool is
contained in the bio_set so stacking drivers can ensure forward
progress.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <axboe@carl.(none)>
2009-07-01 10:56:25 +02:00
Jens Axboe
6118b70b3a cfq-iosched: get rid of the need for __GFP_NOFAIL in cfq_find_alloc_queue()
Setup an emergency fallback cfqq that we allocate at IO scheduler init
time. If the slab allocation fails in cfq_find_alloc_queue(), we'll just
punt IO to that cfqq instead. This ensures that cfq_find_alloc_queue()
never fails without having to ensure free memory.

On cfqq lookup, always try to allocate a new cfqq if the given cfq io
context has the oom_cfqq assigned. This ensures that we only temporarily
punt to this shared queue.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-01 10:56:25 +02:00
Jens Axboe
d5036d770f cfq-iosched: move cfqq initialization out of cfq_find_alloc_queue()
We're going to be needing that init code outside of that function
to get rid of the __GFP_NOFAIL in cfqq allocation.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-01 10:56:25 +02:00
Tejun Heo
245b2e70ea percpu: clean up percpu variable definitions
Percpu variable definition is about to be updated such that all percpu
symbols including the static ones must be unique.  Update percpu
variable definitions accordingly.

* as,cfq: rename ioc_count uniquely

* cpufreq: rename cpu_dbs_info uniquely

* xen: move nesting_count out of xen_evtchn_do_upcall() and rename it

* mm: move ratelimits out of balance_dirty_pages_ratelimited_nr() and
  rename it

* ipv4,6: rename cookie_scratch uniquely

* x86 perf_counter: rename prev_left to pmc_prev_left, irq_entry to
  pmc_irq_entry and nmi_entry to pmc_nmi_entry

* perf_counter: rename disable_count to perf_disable_count

* ftrace: rename test_event_disable to ftrace_test_event_disable

* kmemleak: rename test_pointer to kmemleak_test_pointer

* mce: rename next_interval to mce_next_interval

[ Impact: percpu usage cleanups, no duplicate static percpu var names ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: linux-mm <linux-mm@kvack.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andi Kleen <andi@firstfloor.org>
2009-06-24 15:13:48 +09:00
FUJITA Tomonori
1119865935 block: revert "bsg: setting rq->bio to NULL"
The SMP handler (sas_smp_request) was fixed to use the block API
properly, so we don't need this workaround to avoid blk_put_request()
warning.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-06-21 10:52:42 -05:00
Randy Dunlap
f740f5ca05 Fix kernel-doc parameter name typo in blk-settings.c:
Warning(block/blk-settings.c:108): No description found for parameter 'lim'
Warning(block/blk-settings.c:108): Excess function parameter 'limits' description in 'blk_set_default_limits'

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-19 09:18:32 +02:00
Bartlomiej Zolnierkiewicz
90c699a9ee block: rename CONFIG_LBD to CONFIG_LBDAF
Follow-up to "block: enable by default support for large devices
and files on 32-bit archs".

Rename CONFIG_LBD to CONFIG_LBDAF to:
- allow update of existing [def]configs for "default y" change
- reflect that it is used also for large files support nowadays

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-19 08:08:50 +02:00
Martin K. Petersen
3a02c8e814 block: Fix bounce_pfn setting
Correct stacking bounce_pfn limit setting and prevent warnings on
32-bit.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-18 09:56:20 +02:00
Linus Torvalds
6fd03301d7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (64 commits)
  debugfs: use specified mode to possibly mark files read/write only
  debugfs: Fix terminology inconsistency of dir name to mount debugfs filesystem.
  xen: remove driver_data direct access of struct device from more drivers
  usb: gadget: at91_udc: remove driver_data direct access of struct device
  uml: remove driver_data direct access of struct device
  block/ps3: remove driver_data direct access of struct device
  s390: remove driver_data direct access of struct device
  parport: remove driver_data direct access of struct device
  parisc: remove driver_data direct access of struct device
  of_serial: remove driver_data direct access of struct device
  mips: remove driver_data direct access of struct device
  ipmi: remove driver_data direct access of struct device
  infiniband: ehca: remove driver_data direct access of struct device
  ibmvscsi: gadget: at91_udc: remove driver_data direct access of struct device
  hvcs: remove driver_data direct access of struct device
  xen block: remove driver_data direct access of struct device
  thermal: remove driver_data direct access of struct device
  scsi: remove driver_data direct access of struct device
  pcmcia: remove driver_data direct access of struct device
  PCIE: remove driver_data direct access of struct device
  ...

Manually fix up trivial conflicts due to different direct driver_data
direct access fixups in drivers/block/{ps3disk.c,ps3vram.c}
2009-06-16 12:57:37 -07:00
Li Zefan
e212d6f250 block: remove some includings of blktrace_api.h
When porting blktrace to tracepoints, we changed to trace/block.h
for trace prober declarations.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-16 11:19:36 +02:00
Martin K. Petersen
e475bba2fd block: Introduce helper to reset queue limits to default values
DM reuses the request queue when swapping in a new device table
Introduce blk_set_default_limits() which can be used to reset the the
queue_limits prior to stacking devices.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-16 08:23:52 +02:00
Jeff Moyer
6923715ae3 cfq: remove extraneous '\n' in blktrace output
I noticed a blank line in blktrace output.  This patch fixes that.

Signed-off-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-16 08:21:04 +02:00
Jens Axboe
0989a025d2 block: don't overwrite bdi->state after bdi_init() has been run
Move the defaults to where we do the init of the backing_dev_info.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-16 08:21:03 +02:00
Gui Jianfeng
81be834713 cfq: cleanup for last_end_request in cfq_data
Actually, last_end_request in cfq_data isn't used now. So lets
just remove it.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-16 08:21:03 +02:00
Kay Sievers
2bdf914915 Driver Core: bsg: add nodename for bsg driver
This adds support to the BSG driver to report the proper device name to
userspace for the bsg devices.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-06-15 21:30:26 -07:00
Kay Sievers
b03f38b685 Driver Core: block: add nodename support for block drivers.
This adds support for block drivers to report their requested nodename
to userspace.  It also updates a number of block drivers to provide the
needed subdirectory and device name to be used for them.

Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Jan Blunck <jblunck@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-06-15 21:30:25 -07:00
Randy Dunlap
8ebf975608 block: fix kernel-doc in recent block/ changes
Fix kernel-doc warnings in recently changed block/ source code.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-06-11 20:14:23 -07:00
Linus Torvalds
c9059598ea Merge branch 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.31' of git://git.kernel.dk/linux-2.6-block: (153 commits)
  block: add request clone interface (v2)
  floppy: fix hibernation
  ramdisk: remove long-deprecated "ramdisk=" boot-time parameter
  fs/bio.c: add missing __user annotation
  block: prevent possible io_context->refcount overflow
  Add serial number support for virtio_blk, V4a
  block: Add missing bounce_pfn stacking and fix comments
  Revert "block: Fix bounce limit setting in DM"
  cciss: decode unit attention in SCSI error handling code
  cciss: Remove no longer needed sendcmd reject processing code
  cciss: change SCSI error handling routines to work with interrupts enabled.
  cciss: separate error processing and command retrying code in sendcmd_withirq_core()
  cciss: factor out fix target status processing code from sendcmd functions
  cciss: simplify interface of sendcmd() and sendcmd_withirq()
  cciss: factor out core of sendcmd_withirq() for use by SCSI error handling code
  cciss: Use schedule_timeout_uninterruptible in SCSI error handling code
  block: needs to set the residual length of a bidi request
  Revert "block: implement blkdev_readpages"
  block: Fix bounce limit setting in DM
  Removed reference to non-existing file Documentation/PCI/PCI-DMA-mapping.txt
  ...

Manually fix conflicts with tracing updates in:
	block/blk-sysfs.c
	drivers/ide/ide-atapi.c
	drivers/ide/ide-cd.c
	drivers/ide/ide-floppy.c
	drivers/ide/ide-tape.c
	include/trace/events/block.h
	kernel/trace/blktrace.c
2009-06-11 11:10:35 -07:00
Linus Torvalds
27951daa71 Merge branch 'for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
* 'for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: (28 commits)
  ide-tape: fix debug call
  alim15x3: Remove historical hacks, re-enable init_hwif for PowerPC
  ide-dma: don't reset request fields on dma_timeout_retry()
  ide: drop rq->data handling from ide_map_sg()
  ide-atapi: kill unused fields and callbacks
  ide-tape: simplify read/write functions
  ide-tape: use byte size instead of sectors on rw issue functions
  ide-tape: unify r/w init paths
  ide-tape: kill idetape_bh
  ide-tape: use standard data transfer mechanism
  ide-tape: use single continuous buffer
  ide-atapi,tape,floppy: allow ->pc_callback() to change rq->data_len
  ide-tape,floppy: fix failed command completion after request sense
  ide-pm: don't abuse rq->data
  ide-cd,atapi: use bio for internal commands
  ide-atapi: convert ide-{floppy,tape} to using preallocated sense buffer
  ide-cd: convert to using generic sense request
  ide: add helpers for preparing sense requests
  ide-cd: don't abuse rq->buffer
  ide-atapi: don't abuse rq->buffer
  ...
2009-06-11 10:00:03 -07:00
Kiyoshi Ueda
b0fd271d5f block: add request clone interface (v2)
This patch adds the following 2 interfaces for request-stacking drivers:

  - blk_rq_prep_clone(struct request *clone, struct request *orig,
		      struct bio_set *bs, gfp_t gfp_mask,
		      int (*bio_ctr)(struct bio *, struct bio*, void *),
		      void *data)
      * Clones bios in the original request to the clone request
        (bio_ctr is called for each cloned bios.)
      * Copies attributes of the original request to the clone request.
        The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not
        copied.

  - blk_rq_unprep_clone(struct request *clone)
      * Frees cloned bios from the clone request.

Request stacking drivers (e.g. request-based dm) need to make a clone
request for a submitted request and dispatch it to other devices.

To allocate request for the clone, request stacking drivers may not
be able to use blk_get_request() because the allocation may be done
in an irq-disabled context.
So blk_rq_prep_clone() takes a request allocated by the caller
as an argument.

For each clone bio in the clone request, request stacking drivers
should be able to set up their own completion handler.
So blk_rq_prep_clone() takes a callback function which is called
for each clone bio, and a pointer for private data which is passed
to the callback.

NOTE:
blk_rq_prep_clone() doesn't copy any actual data of the original
request.  Pages are shared between original bios and cloned bios.
So caller must not complete the original request before the clone
request.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-11 13:11:05 +02:00
Linus Torvalds
8623661180 Merge branch 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'tracing-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (244 commits)
  Revert "x86, bts: reenable ptrace branch trace support"
  tracing: do not translate event helper macros in print format
  ftrace/documentation: fix typo in function grapher name
  tracing/events: convert block trace points to TRACE_EVENT(), fix !CONFIG_BLOCK
  tracing: add protection around module events unload
  tracing: add trace_seq_vprint interface
  tracing: fix the block trace points print size
  tracing/events: convert block trace points to TRACE_EVENT()
  ring-buffer: fix ret in rb_add_time_stamp
  ring-buffer: pass in lockdep class key for reader_lock
  tracing: add annotation to what type of stack trace is recorded
  tracing: fix multiple use of __print_flags and __print_symbolic
  tracing/events: fix output format of user stack
  tracing/events: fix output format of kernel stack
  tracing/trace_stack: fix the number of entries in the header
  ring-buffer: discard timestamps that are at the start of the buffer
  ring-buffer: try to discard unneeded timestamps
  ring-buffer: fix bug in ring_buffer_discard_commit
  ftrace: do not profile functions when disabled
  tracing: make trace pipe recognize latency format flag
  ...
2009-06-10 19:53:40 -07:00
Nikanth Karthikesan
d9c7d394a8 block: prevent possible io_context->refcount overflow
Currently io_context has an atomic_t(32-bit) as refcount.  In the case of
cfq, for each device against whcih a task does I/O, a reference to the
io_context would be taken.  And when there are multiple process sharing
io_contexts(CLONE_IO) would also have a reference to the same io_context.

Theoretically the possible maximum number of processes sharing the same
io_context + the number of disks/cfq_data referring to the same io_context
can overflow the 32-bit counter on a very high-end machine.

Even though it is an improbable case, let us make it atomic_long_t.

Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-10 23:07:15 +02:00
Li Zefan
55782138e4 tracing/events: convert block trace points to TRACE_EVENT()
TRACE_EVENT is a more generic way to define tracepoints. Doing so adds
these new capabilities to this tracepoint:

  - zero-copy and per-cpu splice() tracing
  - binary tracing without printf overhead
  - structured logging records exposed under /debug/tracing/events
  - trace events embedded in function tracer output and other plugins
  - user-defined, per tracepoint filter expressions
  ...

Cons:

  - no dev_t info for the output of plug, unplug_timer and unplug_io events.
    no dev_t info for getrq and sleeprq events if bio == NULL.
    no dev_t info for rq_abort,...,rq_requeue events if rq->rq_disk == NULL.

    This is mainly because we can't get the deivce from a request queue.
    But this may change in the future.

  - A packet command is converted to a string in TP_assign, not TP_print.
    While blktrace do the convertion just before output.

    Since pc requests should be rather rare, this is not a big issue.

  - In blktrace, an event can have 2 different print formats, but a TRACE_EVENT
    has a unique format, which means we have some unused data in a trace entry.

    The overhead is minimized by using __dynamic_array() instead of __array().

I've benchmarked the ioctl blktrace vs the splice based TRACE_EVENT tracing:

      dd                   dd + ioctl blktrace       dd + TRACE_EVENT (splice)
1     7.36s, 42.7 MB/s     7.50s, 42.0 MB/s          7.41s, 42.5 MB/s
2     7.43s, 42.3 MB/s     7.48s, 42.1 MB/s          7.43s, 42.4 MB/s
3     7.38s, 42.6 MB/s     7.45s, 42.2 MB/s          7.41s, 42.5 MB/s

So the overhead of tracing is very small, and no regression when using
those trace events vs blktrace.

And the binary output of TRACE_EVENT is much smaller than blktrace:

 # ls -l -h
 -rw-r--r-- 1 root root 8.8M 06-09 13:24 sda.blktrace.0
 -rw-r--r-- 1 root root 195K 06-09 13:24 sda.blktrace.1
 -rw-r--r-- 1 root root 2.7M 06-09 13:25 trace_splice.out

Following are some comparisons between TRACE_EVENT and blktrace:

plug:
  kjournald-480   [000]   303.084981: block_plug: [kjournald]
  kjournald-480   [000]   303.084981:   8,0    P   N [kjournald]

unplug_io:
  kblockd/0-118   [000]   300.052973: block_unplug_io: [kblockd/0] 1
  kblockd/0-118   [000]   300.052974:   8,0    U   N [kblockd/0] 1

remap:
  kjournald-480   [000]   303.085042: block_remap: 8,0 W 102736992 + 8 <- (8,8) 33384
  kjournald-480   [000]   303.085043:   8,0    A   W 102736992 + 8 <- (8,8) 33384

bio_backmerge:
  kjournald-480   [000]   303.085086: block_bio_backmerge: 8,0 W 102737032 + 8 [kjournald]
  kjournald-480   [000]   303.085086:   8,0    M   W 102737032 + 8 [kjournald]

getrq:
  kjournald-480   [000]   303.084974: block_getrq: 8,0 W 102736984 + 8 [kjournald]
  kjournald-480   [000]   303.084975:   8,0    G   W 102736984 + 8 [kjournald]

  bash-2066  [001]  1072.953770:   8,0    G   N [bash]
  bash-2066  [001]  1072.953773: block_getrq: 0,0 N 0 + 0 [bash]

rq_complete:
  konsole-2065  [001]   300.053184: block_rq_complete: 8,0 W () 103669040 + 16 [0]
  konsole-2065  [001]   300.053191:   8,0    C   W 103669040 + 16 [0]

  ksoftirqd/1-7   [001]  1072.953811:   8,0    C   N (5a 00 08 00 00 00 00 00 24 00) [0]
  ksoftirqd/1-7   [001]  1072.953813: block_rq_complete: 0,0 N (5a 00 08 00 00 00 00 00 24 00) 0 + 0 [0]

rq_insert:
  kjournald-480   [000]   303.084985: block_rq_insert: 8,0 W 0 () 102736984 + 8 [kjournald]
  kjournald-480   [000]   303.084986:   8,0    I   W 102736984 + 8 [kjournald]

Changelog from v2 -> v3:

- use the newly introduced __dynamic_array().

Changelog from v1 -> v2:

- use __string() instead of __array() to minimize the memory required
  to store hex dump of rq->cmd().

- support large pc requests.

- add missing blk_fill_rwbs_rq() in block_rq_requeue TRACE_EVENT.

- some cleanups.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A2DF669.5070905@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2009-06-09 12:34:23 -04:00
FUJITA Tomonori
c1d4c41f2f bsg: setting rq->bio to NULL
Due to commit 1cd96c242a ("block: WARN
in __blk_put_request() for potential bio leak"), BSG SMP requests get
the false warnings:

WARNING: at block/blk-core.c:1068 __blk_put_request+0x52/0xc0()

This sets rq->bio to NULL to avoid that false warnings.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-09 15:17:37 +02:00
Martin K. Petersen
77634f33d4 block: Add missing bounce_pfn stacking and fix comments
DM no longer needs to set limits explicitly when calling blk_stack_limits.
Let the latter automatically deal with bounce_pfn scaling.

Fix kerneldoc variable names.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-09 06:23:22 +02:00
Jens Axboe
9df1bb9b51 Revert "block: Fix bounce limit setting in DM"
This reverts commit a05c0205ba.

DM doesn't need to access the bounce_pfn directly.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-09 06:22:57 +02:00
FUJITA Tomonori
dbb66c4be0 block: needs to set the residual length of a bidi request
Tejun's "block: set rq->resid_len to blk_rq_bytes() on issue" patch
seems to be incomplete; It doesn't set rq->resid_len to blk_rq_bytes()
for a bidi request (req->next_rq). As a result, all bidi users are
broken.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-09 05:47:10 +02:00
Martin K. Petersen
a05c0205ba block: Fix bounce limit setting in DM
blk_queue_bounce_limit() is more than a wrapper about the request queue
limits.bounce_pfn variable.  Introduce blk_queue_bounce_pfn() which can
be called by stacking drivers that wish to set the bounce limit
explicitly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-03 09:33:18 +02:00
Kiyoshi Ueda
53c663ce0f block: fix a possible oops on elv_abort_queue()
I found one more mis-conversion to the 'request is always dequeued
when completing' model in elv_abort_queue() during code inspection.
Although I haven't hit any problem caused by this mis-conversion yet
and just done compile/boot test, please apply if you have no problem.

Request must be dequeued when it completes.
However, elv_abort_queue() completes requests without dequeueing.
This will cause oops in the __blk_end_request_all().
This patch fixes the oops.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-02 08:44:01 +02:00
James Bottomley
c143dc903d block: fix an oops on BLKPREP_KILL
Doing a bit of torture testing, I ran across a BUG in the block
subsystem (at blk-core.c:2048): the test for if the request is queued.

It turns out the trigger was a BLKPREP_KILL coming out of the SCSI prep
function.  Currently for BLKPREP_KILL requests, we send them straight
into __blk_end_request_all() with an error, but they've never been
dequeued, so they trip the bug.  Fix this by starting requests before
killing them.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-30 06:43:49 +02:00
Mike Snitzer
5d85d3247c block: export blk_stack_limits()
DM needs to use blk_stack_limits(), so it needs to be exported.

Acked-by: Martin K. Petersen <martin.petersen@oracle.com>

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-28 11:04:53 +02:00
Kiyoshi Ueda
3c4198e874 block: fix no diskstat problem
The commit below in 2.6-block/for-2.6.31 causes no diskstat problem
because the blk_discard_rq() check was added with '&&'.
It should be 'blk_fs_request() || blk_discard_rq()'.
This patch does it and fixes the no diskstat problem.
Please review and apply.

------ /proc/diskstat without this patch -------------------------------------
   8       0 sda 0 0 0 0 0 0 0 0 0 0 0
------------------------------------------------------------------------------

----- /proc/diskstat with this patch applied ---------------------------------
   8       0 sda 4186 303 373621 61600 9578 3859 107468 169479 2 89755 231059
------------------------------------------------------------------------------

--------------------------------------------------------------------------
commit c69d48540c
Author: Jens Axboe <jens.axboe@oracle.com>
Date:   Fri Apr 24 08:12:19 2009 +0200

    block: include discard requests in IO accounting

    We currently don't do merging on discard requests, but we potentially
    could. If we do, then we need to include discard requests in the IO
    accounting, or merging would end up decrementing in_flight IO counters
    for an IO which never incremented them.

    So enable accounting for discard requests.

<snip>

 static inline int blk_do_io_stat(struct request *rq)
 {
-       return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq);
+       return rq->rq_disk && blk_rq_io_stat(rq) && blk_fs_request(rq) &&
+               blk_discard_rq(rq);
 }
--------------------------------------------------------------------------

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-27 14:50:02 +02:00
James Bottomley
ba396a6c10 block: fix oops with block tag queueing
commit e8939a50466fd963eb1ba9118c34b9ffb7ff6aa6
Author: Tejun Heo <tj@kernel.org>
Date:   Fri May 8 11:54:16 2009 +0900

    block: implement and enforce request peek/start/fetch

Added a BUG_ON(blk_queued_rq(req)) to the top of blk_finish_req().
Unfortunately, this checks whether req->queuelist is empty.  This list
is doing double duty both as the queue list and the tag list, so tagged
requests come in here with this not empty and boom (the tag list is
emptied by blk_queue_end_tag() lower down).

Fix this by moving the BUG_ON to below the end tag we also seem
vulnerable to this in blk_requeue_request() as well.  I think all uses
of blk_queued_rq() need auditing because the check is clearly wrong in
the tagged case.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-27 14:17:08 +02:00
Martin K. Petersen
c72758f337 block: Export I/O topology for block devices and partitions
To support devices with physical block sizes bigger than 512 bytes we
need to ensure proper alignment.  This patch adds support for exposing
I/O topology characteristics as devices are stacked.

  logical_block_size is the smallest unit the device can address.

  physical_block_size indicates the smallest I/O the device can write
  without incurring a read-modify-write penalty.

  The io_min parameter is the smallest preferred I/O size reported by
  the device.  In many cases this is the same as the physical block
  size.  However, the io_min parameter can be scaled up when stacking
  (RAID5 chunk size > physical block size).

  The io_opt characteristic indicates the optimal I/O size reported by
  the device.  This is usually the stripe width for arrays.

  The alignment_offset parameter indicates the number of bytes the start
  of the device/partition is offset from the device's natural alignment.
  Partition tools and MD/DM utilities can use this to pad their offsets
  so filesystems start on proper boundaries.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:55 +02:00
Martin K. Petersen
cd43e26f07 block: Expose stacked device queues in sysfs
Currently stacking devices do not have a queue directory in sysfs.
However, many of the I/O characteristics like sector size, maximum
request size, etc. are queue properties.

This patch enables the queue directory for MD/DM devices.  The elevator
code has been modified to deal with queues that do not have an I/O
scheduler.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:55 +02:00
Martin K. Petersen
025146e13b block: Move queue limits to an embedded struct
To accommodate stacking drivers that do not have an associated request
queue we're moving the limits to a separate, embedded structure.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:55 +02:00
Martin K. Petersen
ae03bf639a block: Use accessor functions for queue limits
Convert all external users of queue limits to using wrapper functions
instead of poking the request queue variables directly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:54 +02:00
Martin K. Petersen
e1defc4ff0 block: Do away with the notion of hardsect_size
Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case.  The
sector size will be 4KB but the logical block size will remain
512-bytes.  Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:54 +02:00
Jens Axboe
e4b636366c Merge branch 'master' into for-2.6.31
Conflicts:
	drivers/block/hd.c
	drivers/block/mg_disk.c

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 20:25:34 +02:00
Jens Axboe
0a7ae2ff0d block: change the tag sync vs async restriction logic
Make them fully share the tag space, but disallow async requests using
the last any two slots.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-20 08:54:31 +02:00