Commit Graph

1288 Commits

Author SHA1 Message Date
Martin K. Petersen
c77a5710b7 block: Export max number of segments and max segment size in sysfs
These two values are useful when debugging issues surrounding maximum
I/O size.  Put them in sysfs with the rest of the queue limits.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-15 12:48:00 +01:00
Martin K. Petersen
2cda2728aa block: Fix overrun in lcm() and move it to lib
lcm() was defined to take integer-sized arguments.  The supplied
arguments are multiplied, however, causing us to overflow given
sufficiently large input.  That in turn led to incorrect optimal I/O
size reporting in some cases (RAID over RAID).

Switch lcm() over to unsigned long similar to gcd() and move the
function from blk-settings.c to lib.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-15 12:47:59 +01:00
Linus Torvalds
c32da02342 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (56 commits)
  doc: fix typo in comment explaining rb_tree usage
  Remove fs/ntfs/ChangeLog
  doc: fix console doc typo
  doc: cpuset: Update the cpuset flag file
  Fix of spelling in arch/sparc/kernel/leon_kernel.c no longer needed
  Remove drivers/parport/ChangeLog
  Remove drivers/char/ChangeLog
  doc: typo - Table 1-2 should refer to "status", not "statm"
  tree-wide: fix typos "ass?o[sc]iac?te" -> "associate" in comments
  No need to patch AMD-provided drivers/gpu/drm/radeon/atombios.h
  devres/irq: Fix devm_irq_match comment
  Remove reference to kthread_create_on_cpu
  tree-wide: Assorted spelling fixes
  tree-wide: fix 'lenght' typo in comments and code
  drm/kms: fix spelling in error message
  doc: capitalization and other minor fixes in pnp doc
  devres: typo fix s/dev/devm/
  Remove redundant trailing semicolons from macros
  fix typo "definetly" -> "definitely" in comment
  tree-wide: s/widht/width/g typo in comments
  ...

Fix trivial conflict in Documentation/laptops/00-INDEX
2010-03-12 16:04:50 -08:00
Ben Blum
67523c48aa cgroups: blkio subsystem as module
Modify the Block I/O cgroup subsystem to be able to be built as a module.
As the CFQ disk scheduler optionally depends on blk-cgroup, config options
in block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are
enhanced to support the new module dependency.

Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-12 15:52:36 -08:00
Jiri Kosina
318ae2edc3 Merge branch 'for-next' into for-linus
Conflicts:
	Documentation/filesystems/proc.txt
	arch/arm/mach-u300/include/mach/debug-macro.S
	drivers/net/qlge/qlge_ethtool.c
	drivers/net/qlge/qlge_main.c
	drivers/net/typhoon.c
2010-03-08 16:55:37 +01:00
Emese Revfy
52cf25d0ab Driver core: Constify struct sysfs_ops in struct kobj_type
Constify struct sysfs_ops.

This is part of the ops structure constification
effort started by Arjan van de Ven et al.

Benefits of this constification:

 * prevents modification of data that is shared
   (referenced) by many other structure instances
   at runtime

 * detects/prevents accidental (but not intentional)
   modification attempts on archs that enforce
   read-only kernel data at runtime

 * potentially better optimized code as the compiler
   can assume that the const data cannot be changed

 * the compiler/linker move const data into .rodata
   and therefore exclude them from false sharing

Signed-off-by: Emese Revfy <re.emese@gmail.com>
Acked-by: David Teigland <teigland@redhat.com>
Acked-by: Matt Domsch <Matt_Domsch@dell.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Acked-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Jens Axboe <jens.axboe@oracle.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-03-07 17:04:49 -08:00
Richard Kennedy
4671a13220 block: don't access jiffies when initialising io_context
As the comment says the initial value of last_waited is never used, so
there is no need to initialise it with the current jiffies. Jiffies is
hot enough without accessing it for no reason.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-01 10:57:22 +01:00
Richard Kennedy
73e9ffdd0c cfq: remove 8 bytes of padding from cfq_rb_root on 64 bit builds
Reorder cfq_rb_root to remove 8 bytes of padding on 64 bit builds.

Consequently removing 56 bytes from cfq_group and 64 bytes from
cfq_data.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-01 10:50:20 +01:00
Shaohua Li
abc3c744d0 cfq-iosched: quantum check tweak
Currently a queue can only dispatch up to 4 requests if there are other queues.
This isn't optimal, device can handle more requests, for example, AHCI can
handle 31 requests. I can understand the limit is for fairness, but we could
do a tweak: if the queue still has a lot of slice left, sounds we could
ignore the limit. Test shows this boost my workload (two thread randread of
a SSD) from 78m/s to 100m/s.
Thanks for suggestions from Corrado and Vivek for the patch.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-01 09:20:54 +01:00
Corrado Zoccolo
53c583d226 cfq-iosched: requests "in flight" vs "in driver" clarification
Counters for requests "in flight" and "in driver" are used asymmetrically
in cfq_may_dispatch, and have slightly different meaning.
We split the rq_in_flight counter (was sync_flight) to count both sync
and async requests, in order to use this one, which is more accurate in
some corner cases.
The rq_in_driver counter is coalesced, since individual sync/async counts
are not used any more.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-28 19:45:05 +01:00
Corrado Zoccolo
41647e7a91 cfq-iosched: rethink seeky detection for SSDs
CFQ currently applies the same logic of detecting seeky queues and
grouping them together for rotational disks as well as SSDs.
For SSDs, the time to complete a request doesn't depend on the
request location, but only on the size.
This patch therefore changes the criterion to group queues by
request size in case of SSDs, in order to achieve better fairness.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-28 19:41:25 +01:00
Corrado Zoccolo
3dde36ddea cfq-iosched: rework seeky detection
Current seeky detection is based on average seek lenght.
This is suboptimal, since the average will not distinguish between:
* a process doing medium sized seeks
* a process doing some sequential requests interleaved with larger seeks
and even a medium seek can take lot of time, if the requested sector
happens to be behind the disk head in the rotation (50% probability).

Therefore, we change the seeky queue detection to work as follows:
* each request can be classified as sequential if it is very close to
  the current head position, i.e. it is likely in the disk cache (disks
  usually read more data than requested, and put it in cache for
  subsequent reads). Otherwise, the request is classified as seeky.
* an history window of the last 32 requests is kept, storing the
  classification result.
* A queue is marked as seeky if more than 1/8 of the last 32 requests
  were seeky.

This patch fixes a regression reported by Yanmin, on mmap 64k random
reads.

Reported-by: Yanmin Zhang <yanmin_zhang@linux.intel.com>
Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-28 19:41:25 +01:00
Martin K. Petersen
8a78362c4e block: Consolidate phys_segment and hw_segment limits
Except for SCSI no device drivers distinguish between physical and
hardware segment limits.  Consolidate the two into a single segment
limit.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26 13:58:08 +01:00
Martin K. Petersen
086fa5ff08 block: Rename blk_queue_max_sectors to blk_queue_max_hw_sectors
The block layer calling convention is blk_queue_<limit name>.
blk_queue_max_sectors predates this practice, leading to some confusion.
Rename the function to appropriately reflect that its intended use is to
set max_hw_sectors.

Also introduce a temporary wrapper for backwards compability.  This can
be removed after the merge window is closed.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26 13:58:08 +01:00
Martin K. Petersen
eb28d31bc9 block: Add BLK_ prefix to definitions
Add a BLK_ prefix to block layer constants.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26 13:58:08 +01:00
Martin K. Petersen
e751e76a5f block: Remove unused accessor function
blk_queue_max_hw_sectors is no longer called by any subsystem and can be
removed.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26 13:58:07 +01:00
Martin K. Petersen
2800aac111 block: Update blk_queue_max_sectors and documentation
Clarify blk_queue_max_sectors and update documentation.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26 13:58:07 +01:00
Gui Jianfeng
024f906616 cfq: Remove useless css reference get
There's no need to take css reference here, for the caller
has already called rcu_read_lock() to prevent cgroup from
being removed.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-26 08:56:15 +01:00
Jens Axboe
7f03292ee1 Merge branch 'master' into for-2.6.34
Conflicts:
	include/linux/blkdev.h

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-25 08:48:05 +01:00
Akinobu Mita
bddd87c7e6 blk-core: use BIO list management functions
Now that the bio list management stuff is generic, convert
generic_make_request to use bio lists instead of its own private bio
list implementation.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-23 08:55:42 +01:00
Jens Axboe
79da0644a8 Revert "block: improve queue_should_plug() by looking at IO depths"
This reverts commit fb1e75389b.

"Benjamin S." <sbenni@gmx.de> reports that the patch in question
causes a big drop in sequential throughput for him, dropping from
200MB/sec down to only 70MB/sec.

Needs to be investigated more fully, for now lets just revert the
offending commit.

Conflicts:

	include/linux/blkdev.h

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-23 08:40:43 +01:00
Richard Kennedy
c4081ba5c9 cfq: reorder cfq_queue removing padding on 64bit
This removes 8 bytes of padding from struct cfq_queue on 64 bit builds,
shrinking it's size to 256 bytes, so fitting into 1 fewer cachelines and
allowing 1 more object/slab in it's kmem_cache.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
----
patch against 2.6.33-rc8
tested on x86_64 AMDX2
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-22 13:49:24 +01:00
Jens Axboe
f11cbd74c5 Merge branch 'master' into for-2.6.34 2010-02-22 13:48:51 +01:00
Daniel Mack
3ad2f3fbb9 tree-wide: Assorted spelling fixes
In particular, several occurances of funny versions of 'success',
'unknown', 'therefore', 'acknowledge', 'argument', 'achieve', 'address',
'beginning', 'desirable', 'separate' and 'necessary' are fixed.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Cc: Joe Perches <joe@perches.com>
Cc: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-02-09 11:13:56 +01:00
Shaohua Li
ae54abed63 cfq-iosched: split seeky coop queues after one slice
Currently we split seeky coop queues after 1s, which is too big. Below patch
marks seeky coop queue split_coop flag after one slice. After that, if new
requests come in, the queues will be splitted. Patch is suggested by Corrado.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-05 13:11:45 +01:00
Vivek Goyal
1efe8fe1c2 cfq-iosched: Do not idle on async queues
Few weeks back, Shaohua Li had posted similar patch. I am reposting it
with more test results.

This patch does two things.

- Do not idle on async queues.

- It also changes the write queue depth CFQ drives (cfq_may_dispatch()).
  Currently, we seem to driving queue depth of 1 always for WRITES. This is
  true even if there is only one write queue in the system and all the logic
  of infinite queue depth in case of single busy queue as well as slowly
  increasing queue depth based on last delayed sync request does not seem to
  be kicking in at all.

This patch will allow deeper WRITE queue depths (subjected to the other
WRITE queue depth contstraints like cfq_quantum and last delayed sync
request).

Shaohua Li had reported getting more out of his SSD. For me, I have got
one Lun exported from an HP EVA and when pure buffered writes are on, I
can get more out of the system. Following are test results of pure
buffered writes (with end_fsync=1) with vanilla and patched kernel. These
results are average of 3 sets of run with increasing number of threads.

AVERAGE[bufwfs][vanilla]
-------
job       Set NR  ReadBW(KB/s)   MaxClat(us)    WriteBW(KB/s)  MaxClat(us)
---       --- --  ------------   -----------    -------------  -----------
bufwfs    3   1   0              0              95349          474141
bufwfs    3   2   0              0              100282         806926
bufwfs    3   4   0              0              109989         2.7301e+06
bufwfs    3   8   0              0              116642         3762231
bufwfs    3   16  0              0              118230         6902970

AVERAGE[bufwfs] [patched kernel]
-------
bufwfs    3   1   0              0              270722         404352
bufwfs    3   2   0              0              206770         1.06552e+06
bufwfs    3   4   0              0              195277         1.62283e+06
bufwfs    3   8   0              0              260960         2.62979e+06
bufwfs    3   16  0              0              299260         1.70731e+06

I also ran buffered writes along with some sequential reads and some
buffered reads going on in the system on a SATA disk because the potential
risk could be that we should not be driving queue depth higher in presence
of sync IO going to keep the max clat low.

With some random and sequential reads going on in the system on one SATA
disk I did not see any significant increase in max clat. So it looks like
other WRITE queue depth control logic is doing its job. Here are the
results.

AVERAGE[brr, bsr, bufw together] [vanilla]
-------
job       Set NR  ReadBW(KB/s)   MaxClat(us)    WriteBW(KB/s)  MaxClat(us)
---       --- --  ------------   -----------    -------------  -----------
brr       3   1   850            546345         0              0
bsr       3   1   14650          729543         0              0
bufw      3   1   0              0              23908          8274517

brr       3   2   981.333        579395         0              0
bsr       3   2   14149.7        1175689        0              0
bufw      3   2   0              0              21921          1.28108e+07

brr       3   4   898.333        1.75527e+06    0              0
bsr       3   4   12230.7        1.40072e+06    0              0
bufw      3   4   0              0              19722.3        2.4901e+07

brr       3   8   900            3160594        0              0
bsr       3   8   9282.33        1.91314e+06    0              0
bufw      3   8   0              0              18789.3        23890622

AVERAGE[brr, bsr, bufw mixed] [patched kernel]
-------
job       Set NR  ReadBW(KB/s)   MaxClat(us)    WriteBW(KB/s)  MaxClat(us)
---       --- --  ------------   -----------    -------------  -----------
brr       3   1   837            417973         0              0
bsr       3   1   14357.7        591275         0              0
bufw      3   1   0              0              24869.7        8910662

brr       3   2   1038.33        543434         0              0
bsr       3   2   13351.3        1205858        0              0
bufw      3   2   0              0              18626.3        13280370

brr       3   4   913            1.86861e+06    0              0
bsr       3   4   12652.3        1430974        0              0
bufw      3   4   0              0              15343.3        2.81305e+07

brr       3   8   890            2.92695e+06    0              0
bsr       3   8   9635.33        1.90244e+06    0              0
bufw      3   8   0              0              17200.3        24424392

So looks like it might make sense to include this patch.

Thanks
Vivek

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-02 20:46:10 +01:00
Gui Jianfeng
bcf4dd4342 blk-cgroup: Fix potential deadlock in blk-cgroup
I triggered a lockdep warning as following.

=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.33-rc2 #1
-------------------------------------------------------
test_io_control/7357 is trying to acquire lock:
 (blkio_list_lock){+.+...}, at: [<c053a990>] blkiocg_weight_write+0x82/0x9e

but task is already holding lock:
 (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #2 (&(&blkcg->lock)->rlock){......}:
       [<c04583b7>] validate_chain+0x8bc/0xb9c
       [<c0458dba>] __lock_acquire+0x723/0x789
       [<c0458eb0>] lock_acquire+0x90/0xa7
       [<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a
       [<c053a4e1>] blkiocg_add_blkio_group+0x1a/0x6d
       [<c053cac7>] cfq_get_queue+0x225/0x3de
       [<c053eec2>] cfq_set_request+0x217/0x42d
       [<c052c8a6>] elv_set_request+0x17/0x26
       [<c0532a0f>] get_request+0x203/0x2c5
       [<c0532ae9>] get_request_wait+0x18/0x10e
       [<c0533470>] __make_request+0x2ba/0x375
       [<c0531985>] generic_make_request+0x28d/0x30f
       [<c0532da7>] submit_bio+0x8a/0x8f
       [<c04d827a>] submit_bh+0xf0/0x10f
       [<c04d91d2>] ll_rw_block+0xc0/0xf9
       [<f86e9705>] ext3_find_entry+0x319/0x544 [ext3]
       [<f86eae58>] ext3_lookup+0x2c/0xb9 [ext3]
       [<c04c3e1b>] do_lookup+0xd3/0x172
       [<c04c56c8>] link_path_walk+0x5fb/0x95c
       [<c04c5a65>] path_walk+0x3c/0x81
       [<c04c5b63>] do_path_lookup+0x21/0x8a
       [<c04c66cc>] do_filp_open+0xf0/0x978
       [<c04c0c7e>] open_exec+0x1b/0xb7
       [<c04c1436>] do_execve+0xbb/0x266
       [<c04081a9>] sys_execve+0x24/0x4a
       [<c04028a2>] ptregs_execve+0x12/0x18

-> #1 (&(&q->__queue_lock)->rlock){..-.-.}:
       [<c04583b7>] validate_chain+0x8bc/0xb9c
       [<c0458dba>] __lock_acquire+0x723/0x789
       [<c0458eb0>] lock_acquire+0x90/0xa7
       [<c0692b0a>] _raw_spin_lock_irqsave+0x27/0x5a
       [<c053dd2a>] cfq_unlink_blkio_group+0x17/0x41
       [<c053a6eb>] blkiocg_destroy+0x72/0xc7
       [<c0467df0>] cgroup_diput+0x4a/0xb2
       [<c04ca473>] dentry_iput+0x93/0xb7
       [<c04ca4b3>] d_kill+0x1c/0x36
       [<c04cb5c5>] dput+0xf5/0xfe
       [<c04c6084>] do_rmdir+0x95/0xbe
       [<c04c60ec>] sys_rmdir+0x10/0x12
       [<c04027cc>] sysenter_do_call+0x12/0x32

-> #0 (blkio_list_lock){+.+...}:
       [<c0458117>] validate_chain+0x61c/0xb9c
       [<c0458dba>] __lock_acquire+0x723/0x789
       [<c0458eb0>] lock_acquire+0x90/0xa7
       [<c06929fd>] _raw_spin_lock+0x1e/0x4e
       [<c053a990>] blkiocg_weight_write+0x82/0x9e
       [<c0467f1e>] cgroup_file_write+0xc6/0x1c0
       [<c04bd2f3>] vfs_write+0x8c/0x116
       [<c04bd7c6>] sys_write+0x3b/0x60
       [<c04027cc>] sysenter_do_call+0x12/0x32

other info that might help us debug this:

1 lock held by test_io_control/7357:
 #0:  (&(&blkcg->lock)->rlock){......}, at: [<c053a949>] blkiocg_weight_write+0x3b/0x9e
stack backtrace:
Pid: 7357, comm: test_io_control Not tainted 2.6.33-rc2 #1
Call Trace:
 [<c045754f>] print_circular_bug+0x91/0x9d
 [<c0458117>] validate_chain+0x61c/0xb9c
 [<c0458dba>] __lock_acquire+0x723/0x789
 [<c0458eb0>] lock_acquire+0x90/0xa7
 [<c053a990>] ? blkiocg_weight_write+0x82/0x9e
 [<c06929fd>] _raw_spin_lock+0x1e/0x4e
 [<c053a990>] ? blkiocg_weight_write+0x82/0x9e
 [<c053a990>] blkiocg_weight_write+0x82/0x9e
 [<c0467f1e>] cgroup_file_write+0xc6/0x1c0
 [<c0454df5>] ? trace_hardirqs_off+0xb/0xd
 [<c044d93a>] ? cpu_clock+0x2e/0x44
 [<c050e6ec>] ? security_file_permission+0xf/0x11
 [<c04bcdda>] ? rw_verify_area+0x8a/0xad
 [<c0467e58>] ? cgroup_file_write+0x0/0x1c0
 [<c04bd2f3>] vfs_write+0x8c/0x116
 [<c04bd7c6>] sys_write+0x3b/0x60
 [<c04027cc>] sysenter_do_call+0x12/0x32

To prevent deadlock, we should take locks as following sequence:

blkio_list_lock -> queue_lock ->  blkcg_lock.

The following patch should fix this bug.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-02-01 09:58:54 +01:00
Alan D. Brunelle
488991e28e block: Added in stricter no merge semantics for block I/O
Updated 'nomerges' tunable to accept a value of '2' - indicating that _no_
merges at all are to be attempted (not even the simple one-hit cache).

The following table illustrates the additional benefit - 5 minute runs of
a random I/O load were applied to a dozen devices on a 16-way x86_64 system.

nomerges        Throughput      %System         Improvement (tput / %sys)
--------        ------------    -----------     -------------------------
0               12.45 MB/sec    0.669365609
1               12.50 MB/sec    0.641519199     0.40% / 2.71%
2               12.52 MB/sec    0.639849750     0.56% / 2.96%

Signed-off-by: Alan D. Brunelle <alan.brunelle@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-29 09:04:08 +01:00
Divyesh Shah
875feb63b9 cfq-iosched: Respect ioprio_class when preempting
In cfq_should_preempt(), we currently allow some cases where a non-RT request
can preempt an ongoing RT cfqq timeslice. This should not happen.
Examples include:

o A sync_noidle wl type non-RT request pre-empting a sync_noidle wl type cfqq
  on which we are idling.
o Once we have per-cgroup async queues, a non-RT sync request pre-empting a RT
  async cfqq.

Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-11 16:16:18 +01:00
Martin K. Petersen
e03a72e136 block: Stop using byte offsets
All callers of the stacking functions use 512-byte sector units rather
than byte offsets.  Simplify the code so the stacking functions take
sectors when specifying data offsets.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-11 14:30:09 +01:00
Kirill Afonshin
ce289321b7 block: removed unused as_io_context
It isn't used anymore, since AS was deleted.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-11 14:29:20 +01:00
Martin K. Petersen
17be8c2450 block: bdev_stack_limits wrapper
DM does not want to know about partition offsets.  Add a partition-aware
wrapper that DM can use when stacking block devices.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Reviewed-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-11 14:29:20 +01:00
Martin K. Petersen
dd3d145d49 block: Fix discard alignment calculation and printing
Discard alignment reporting for partitions was incorrect.  Update to
match the algorithm used elsewhere.

The alignment can be negative (misaligned).  Fix format string
accordingly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-11 14:29:19 +01:00
Martin K. Petersen
fe0b393f2c block: Correct handling of bottom device misaligment
The top device misalignment flag would not be set if the added bottom
device was already misaligned as opposed to causing a stacking failure.

Also massage the reporting so that an error is only returned if adding
the bottom device caused the misalignment.  I.e. don't return an error
if the top is already flagged as misaligned.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-01-11 14:29:19 +01:00
OGAWA Hirofumi
e79e95db5c block: Honor the gfp_mask for alloc_page() in blkdev_issue_discard()
Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-29 08:53:54 +01:00
Martin K. Petersen
81744ee44a block: Fix incorrect alignment offset reporting and update documentation
queue_sector_alignment_offset returned the wrong value which caused
partitions to report an incorrect alignment_offset.  Since offset
alignment calculation is needed several places it has been split into a
separate helper function.  The topology stacking function has been
updated accordingly.

Furthermore, comments have been added to clarify how the stacking
function works.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Tested-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-29 08:35:35 +01:00
Shaohua Li
2f7a2d89a8 cfq-iosched: don't regard requests with long distance as close
seek_mean could be very big sometimes, using it as close criteria is meaningless
as this doen't improve any performance. So if it's big, let's fallback to
default value.

Reviewed-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Shaohua Li<shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-28 13:18:44 +01:00
Martin K. Petersen
9504e0864b block: Fix topology stacking for data and discard alignment
The stacking code incorrectly scaled up the data offset in some cases
causing misaligned devices to report alignment.  Rewrite the stacking
algorithm to remedy this and apply the same alignment principles to the
discard handling.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-21 15:55:51 +01:00
Vivek Goyal
65b32a573e cfq-iosched: Remove prio_change logic for workload selection
o CFQ now internally divides cfq queues in therr workload categories. sync-idle,
  sync-noidle and async. Which workload to run depends primarily on rb_key
  offset across three service trees. Which is a combination of mulitiple things
  including what time queue got queued on the service tree.

  There is one exception though. That is if we switched the prio class, say
  we served some RT tasks and again started serving BE class, then with-in
  BE class we always started with sync-noidle workload irrespective of rb_key
  offset in service trees.

  This can provide better latencies for sync-noidle workload in the presence
  of RT tasks.

o This patch gets rid of that exception and which workload to run with-in
  class always depends on lowest rb_key across service trees. The reason
  being that now we have multiple BE class groups and if we always switch
  to sync-noidle workload with-in group, we can potentially starve a sync-idle
  workload with-in group. Same is true for async workload which will be in
  root group. Also the workload-switching with-in group will become very
  unpredictable as it now depends whether some RT workload was running in
  the system or not.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Acked-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-18 12:40:21 +01:00
Vivek Goyal
fb104db41e cfq-iosched: Get rid of nr_groups
o Currently code does not seem to be using cfqd->nr_groups. Get rid of it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-18 12:40:21 +01:00
Vivek Goyal
1db32c4060 cfq-iosched: Remove the check for same cfq group from allow_merge
o allow_merge() already checks if submitting task is pointing to same cfqq
  as rq has been queued in. If everything is fine, we should not be having
  a task in one cgroup and having a pointer to cfqq in other cgroup.

  Well I guess in some situations it can happen and that is, when a random
  IO queue has been moved into root cgroup for group_isolation=0. In
  this case, tasks's cgroup/group is different from where actually cfqq is,
  but this is intentional and in this case merging should be allowed.

  The second situation is where due to close cooperator patches, multiple
  processes can be sharing a cfqq. If everything implemented right, we should
  not end up in a situation where tasks from different processes in different
  groups are sharing the same cfqq as we allow merging of cooperating queues
  only if they are in same group.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-18 12:40:21 +01:00
Jens Axboe
b568be627a block: temporarily disable discard granularity
Commit 86b3728141 adds a check for
misaligned stacking offsets, but it's buggy since the defaults are 0.
Hence all dm devices that pass in a non-zero starting offset will
be marked as misaligned amd dm will complain.

A real fix is coming, in the mean time disable the discard granularity
check so that users don't worry about dm reporting about misaligned
devices.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-16 09:16:41 +01:00
Linus Torvalds
51b736b851 Merge branch 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.33' of git://git.kernel.dk/linux-2.6-block:
  cfq: set workload as expired if it doesn't have any slice left
  Fix a CFQ crash in "for-2.6.33" branch of block tree
  cfq: Remove wait_request flag when idle time is being deleted
  cfq-iosched: commenting non-obvious initialization
  cfq-iosched: Take care of corner cases of group losing share due to deletion
  cfq-iosched: Get rid of cfqq wait_busy_done flag
  cfq: Optimization for close cooperating queue searching
  block,xd: Delay allocation of DMA buffers until device is known
  drbd: Following the hmac change to SHASH (see linux commit 8bd1209cff)
  cfq-iosched: reduce write depth only if sync was delayed
2009-12-15 09:11:28 -08:00
Gui Jianfeng
66ae291978 cfq: set workload as expired if it doesn't have any slice left
When a group is resumed, if it doesn't have workload slice left,
we should set workload_expires as expired. Otherwise, we might
start from where we left in previous group by error.
Thanks the idea from Corrado.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-15 10:08:45 +01:00
Vivek Goyal
82bbbf28db Fix a CFQ crash in "for-2.6.33" branch of block tree
I think my previous patch introduced a bug which can lead to CFQ hitting
BUG_ON().

The offending commit in for-2.6.33 branch is.

commit 7667aa0630
Author: Vivek Goyal <vgoyal@redhat.com>
Date:   Tue Dec 8 17:52:58 2009 -0500

    cfq-iosched: Take care of corner cases of group losing share due to deletion

While doing some stress testing on my box, I enountered following.

login: [ 3165.148841] BUG: scheduling while
atomic: swapper/0/0x10000100
[ 3165.149821] Modules linked in: cfq_iosched dm_multipath qla2xxx igb
scsi_transport_fc dm_snapshot [last unloaded: scsi_wait_scan]
[ 3165.149821] Pid: 0, comm: swapper Not tainted
2.6.32-block-for-33-merged-new #3
[ 3165.149821] Call Trace:
[ 3165.149821]  <IRQ>  [<ffffffff8103fab8>] __schedule_bug+0x5c/0x60
[ 3165.149821]  [<ffffffff8103afd7>] ? __wake_up+0x44/0x4d
[ 3165.149821]  [<ffffffff8153a979>] schedule+0xe3/0x7bc
[ 3165.149821]  [<ffffffff8103a796>] ? cpumask_next+0x1d/0x1f
[ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
[cfq_iosched]
[ 3165.149821]  [<ffffffff810422d8>] __cond_resched+0x2a/0x35
[ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
[cfq_iosched]
[ 3165.149821]  [<ffffffff8153b1ee>] _cond_resched+0x2c/0x37
[ 3165.149821]  [<ffffffff8100e2db>] is_valid_bugaddr+0x16/0x2f
[ 3165.149821]  [<ffffffff811e4161>] report_bug+0x18/0xac
[ 3165.149821]  [<ffffffff8100f1fc>] die+0x39/0x63
[ 3165.149821]  [<ffffffff8153cde1>] do_trap+0x11a/0x129
[ 3165.149821]  [<ffffffff8100d470>] do_invalid_op+0x96/0x9f
[ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
[cfq_iosched]
[ 3165.149821]  [<ffffffff81034b4d>] ? enqueue_task+0x5c/0x67
[ 3165.149821]  [<ffffffff8103ae83>] ? task_rq_unlock+0x11/0x13
[ 3165.149821]  [<ffffffff81041aae>] ? try_to_wake_up+0x292/0x2a4
[ 3165.149821]  [<ffffffff8100c935>] invalid_op+0x15/0x20
[ 3165.149821]  [<ffffffffa000b21d>] ? cfq_dispatch_requests+0x6ba/0x93e
[cfq_iosched]
[ 3165.149821]  [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f
[ 3165.149821]  [<ffffffff811d8c2a>] blk_peek_request+0x191/0x1a7
[ 3165.149821]  [<ffffffff811e5b8d>] ? kobject_get+0x1a/0x21
[ 3165.149821]  [<ffffffff812c8d4c>] scsi_request_fn+0x82/0x3df
[ 3165.149821]  [<ffffffff8110b2de>] ? bio_fs_destructor+0x15/0x17
[ 3165.149821]  [<ffffffff810df5a6>] ? virt_to_head_page+0xe/0x2f
[ 3165.149821]  [<ffffffff811d931f>] __blk_run_queue+0x42/0x71
[ 3165.149821]  [<ffffffff811d9403>] blk_run_queue+0x26/0x3a
[ 3165.149821]  [<ffffffff812c8761>] scsi_run_queue+0x2de/0x375
[ 3165.149821]  [<ffffffff812b60ac>] ? put_device+0x17/0x19
[ 3165.149821]  [<ffffffff812c92d7>] scsi_next_command+0x3b/0x4b
[ 3165.149821]  [<ffffffff812c9b9f>] scsi_io_completion+0x1c9/0x3f5
[ 3165.149821]  [<ffffffff812c3c36>] scsi_finish_command+0xb5/0xbe

I think I have hit following BUG_ON() in cfq_dispatch_request().

BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));

Please find attached the patch to fix it. I have done some stress testing
with it and have not seen it happening again.

o We should wait on a queue even after slice expiry only if it is empty. If
  queue is not empty then continue to expire it.

o If we decide to keep the queue then make cfqq=NULL. Otherwise select_queue()
  will return a valid cfqq and cfq_dispatch_request() can hit following
  BUG_ON().

  BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list))

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-10 19:25:41 +01:00
Gui Jianfeng
554554f60a cfq: Remove wait_request flag when idle time is being deleted
Remove wait_request flag when idle time is being deleted, otherwise
it'll hit this path every time when a request is enqueued.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-10 09:38:39 +01:00
Linus Torvalds
4ef58d4e2a Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (42 commits)
  tree-wide: fix misspelling of "definition" in comments
  reiserfs: fix misspelling of "journaled"
  doc: Fix a typo in slub.txt.
  inotify: remove superfluous return code check
  hdlc: spelling fix in find_pvc() comment
  doc: fix regulator docs cut-and-pasteism
  mtd: Fix comment in Kconfig
  doc: Fix IRQ chip docs
  tree-wide: fix assorted typos all over the place
  drivers/ata/libata-sff.c: comment spelling fixes
  fix typos/grammos in Documentation/edac.txt
  sysctl: add missing comments
  fs/debugfs/inode.c: fix comment typos
  sgivwfb: Make use of ARRAY_SIZE.
  sky2: fix sky2_link_down copy/paste comment error
  tree-wide: fix typos "couter" -> "counter"
  tree-wide: fix typos "offest" -> "offset"
  fix kerneldoc for set_irq_msi()
  spidev: fix double "of of" in comment
  comment typo fix: sybsystem -> subsystem
  ...
2009-12-09 19:43:33 -08:00
Corrado Zoccolo
edc71131c4 cfq-iosched: commenting non-obvious initialization
Added a comment to explain the initialization of last_delayed_sync.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-09 20:56:04 +01:00
Vivek Goyal
7667aa0630 cfq-iosched: Take care of corner cases of group losing share due to deletion
If there is a sequential reader running in a group, we wait for next request
to come in that group after slice expiry and once new request is in, we expire
the queue. Otherwise we delete the group from service tree and group looses
its fair share.

So far I was marking a queue as wait_busy if it had consumed its slice and
it was last queue in the group. But this condition did not cover following
two cases.

1.If a request completed and slice has not expired yet. Next request comes
  in and is dispatched to disk. Now select_queue() hits and slice has expired.
  This group will be deleted. Because request is still in the disk, this queue
  will never get a chance to wait_busy.

2.If request completed and slice has not expired yet. Before next request
  comes in (delay due to think time), select_queue() hits and expires the
  queue hence group. This queue never got a chance to wait busy.

Gui was hitting the boundary condition 1 and not getting fairness numbers
proportional to weight.

This patch puts the checks for above two conditions and improves the fairness
numbers for sequential workload on rotational media. Check in select_queue()
takes care of case 1 and additional check in should_wait_busy() takes care
of case 2.

Reported-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-09 15:11:04 +01:00
Vivek Goyal
c244bb50a9 cfq-iosched: Get rid of cfqq wait_busy_done flag
o Get rid of wait_busy_done flag. This flag only tells we were doing wait
  busy on a queue and that queue got request so expire it. That information
  can easily be obtained by (cfq_cfqq_wait_busy() && queue_is_not_empty). So
  remove this flag and keep code simple.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-09 15:11:03 +01:00
Gui Jianfeng
b9d8f4c73b cfq: Optimization for close cooperating queue searching
It doesn't make any sense to try to find out a close cooperating
queue if current cfqq is the only one in the group.

Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-09 15:11:03 +01:00
Corrado Zoccolo
573412b295 cfq-iosched: reduce write depth only if sync was delayed
The introduction of ramp-up formula for async queue depths has
slowed down dirty page reclaim, by reducing async write performance.
This patch makes sure the formula kicks in only when sync request
was recently delayed.

Signed-off-by: Corrado Zoccolo <czoccolo@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-09 12:32:55 +01:00
Vivek Goyal
878eaddd05 cfq-iosched: Do not access cfqq after freeing it
Fix a crash during boot reported by Jeff Moyer. Fix the issue of accessing
cfqq after freeing it.

Reported-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <axboe@carl.(none)>
2009-12-07 19:37:15 +01:00
Stephen Rothwell
accee7854b block: include linux/err.h to use ERR_PTR
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-07 09:47:07 +01:00
Jens Axboe
bb729bc98c cfq-iosched: use call_rcu() instead of doing grace period stall on queue exit
After the merge of the IO controller patches, booting on my megaraid
box ran much slower. Vivek Goyal traced it down to megaraid discovery
creating tons of devices, each suffering a grace period when they later
kill that queue (if no device is found).

So lets use call_rcu() to batch these deferred frees, instead of taking
the grace period hit for each one.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-06 09:54:19 +01:00
Vivek Goyal
846954b0a3 blkio: Allow CFQ group IO scheduling even when CFQ is a module
o Now issues of blkio controller and CFQ in module mode should be fixed.
  Enable the cfq group scheduling support in module mode.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 16:38:14 +01:00
Vivek Goyal
3e25206689 blkio: Implement dynamic io controlling policy registration
o One of the goals of block IO controller is that it should be able to
  support mulitple io control policies, some of which be operational at
  higher level in storage hierarchy.

o To begin with, we had one io controlling policy implemented by CFQ, and
  I hard coded the CFQ functions called by blkio. This created issues when
  CFQ is compiled as module.

o This patch implements a basic dynamic io controlling policy registration
  functionality in blkio. This is similar to elevator functionality where
  ioschedulers register the functions dynamically.

o Now in future, when more IO controlling policies are implemented, these
  can dynakically register with block IO controller.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 16:38:14 +01:00
Vivek Goyal
9d6a986c0b blkio: Export some symbols from blkio as its user CFQ can be a module
o blkio controller is inside the kernel and cfq makes use of interfaces
  exported by blkio. CFQ can be a module too, hence export symbols used
  by CFQ.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 16:38:14 +01:00
Louis Rilling
b69f229206 block: Fix io_context leak after failure of clone with CLONE_IO
With CLONE_IO, parent's io_context->nr_tasks is incremented, but never
decremented whenever copy_process() fails afterwards, which prevents
exit_io_context() from calling IO schedulers exit functions.

Give a task_struct to exit_io_context(), and call exit_io_context() instead of
put_io_context() in copy_process() cleanup path.

Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 16:36:18 +01:00
Louis Rilling
61cc74fbb8 block: Fix io_context leak after clone with CLONE_IO
With CLONE_IO, copy_io() increments both ioc->refcount and ioc->nr_tasks.
However exit_io_context() only decrements ioc->refcount if ioc->nr_tasks
reaches 0.

Always call put_io_context() in exit_io_context().

Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 16:36:18 +01:00
André Goddard Rosa
af901ca181 tree-wide: fix assorted typos all over the place
That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-12-04 15:39:55 +01:00
Shaohua Li
3c764b7a65 cfq-iosched: make nonrot check logic consistent
cfq_arm_slice_timer() has logic to disable idle window for SSD device. The same
thing should be done at cfq_select_queue() too, otherwise we will still see
idle window. This makes the nonrot check logic consistent in cfq.
Tests in a intel SSD with low_latency knob close, below patch can triple disk
thoughput for muti-thread sequential read.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 13:12:06 +01:00
Jens Axboe
237e5bc4e5 io controller: quick fix for blk-cgroup and modular CFQ
It's currently not an allowed configuration, so express that in Kconfig.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 10:07:38 +01:00
Jens Axboe
f2eecb9152 cfq-iosched: move IO controller declerations to a header file
They should not be declared inside some other file that's not related
to CFQ.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 10:06:35 +01:00
Jens Axboe
2f5ea47712 cfq-iosched: fix compile problem with !CONFIG_CGROUP
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 21:07:17 +01:00
Vivek Goyal
c04645e592 blkio: Wait on sync-noidle queue even if rq_noidle = 1
o rq_noidle() is supposed to tell cfq that do not expect a request after this
  one, hence don't idle. But this does not seem to work very well. For example
  for direct random readers, rq_noidle = 1 but there is next request coming
  after this. Not idling, leads to a group not getting its share even if
  group_isolation=1.

o The right solution for this issue is to scan the higher layers and set
  right flag (WRITE_SYNC or WRITE_ODIRECT). For the time being, this single
  line fix helps. This should not have any significant impact when we are
  not using cgroups. I will later figure out IO paths in higher layer and
  fix it.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:53 +01:00
Vivek Goyal
ae30c28655 blkio: Implement group_isolation tunable
o If a group is running only a random reader, then it will not have enough
  traffic to keep disk busy and we will reduce overall throughput. This
  should result in better latencies for random reader though. If we don't
  idle on random reader service tree, then this random reader will experience
  large latencies if there are other groups present in system with sequential
  readers running in these.

o One solution suggested by corrado is that by default keep the random readers
  or sync-noidle workload in root group so that during one dispatch round
  we idle only once on sync-noidle tree. This means that all the sync-idle
  workload queues will be in their respective group and we will see service
  differentiation in those but not on sync-noidle workload.

o Provide a tunable group_isolation. If set, this will make sure that even
  sync-noidle queues go in their respective group and we wait on these. This
  provides stronger isolation between groups but at the expense of throughput
  if group does not have enough traffic to keep the disk busy.

o By default group_isolation = 0

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:53 +01:00
Vivek Goyal
f26bd1f0a3 blkio: Determine async workload length based on total number of queues
o Async queues are not per group. Instead these are system wide and maintained
  in root group. Hence their workload slice length should be calculated
  based on total number of queues in the system and not just queues in the
  root group.

o As root group's default weight is 1000, make sure to charge async queue
  more in terms of vtime so that it does not get more time on disk because
  root group has higher weight.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:53 +01:00
Vivek Goyal
f75edf2dc8 blkio: Wait for cfq queue to get backlogged if group is empty
o If a queue consumes its slice and then gets deleted from service tree, its
  associated group will also get deleted from service tree if this was the
  only queue in the group. That will make group loose its share.

o For the queues on which we have idling on and if these have used their
  slice, wait a bit for these queues to get backlogged again and then
  expire these queues so that group does not loose its share.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:53 +01:00
Vivek Goyal
f8d461d692 blkio: Propagate cgroup weight updation to cfq groups
o Propagate blkio cgroup weight updation to associated cfq groups.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:53 +01:00
Vivek Goyal
24610333d5 blkio: Drop the reference to queue once the task changes cgroup
o If a task changes cgroup, drop reference to the cfqq associated with io
  context and set cfqq pointer stored in ioc to NULL so that upon next request
  arrival we will allocate a  new queue in new group.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
8682e1f15f blkio: Provide some isolation between groups
o Do not allow following three operations across groups for isolation.
	- selection of co-operating queues
	- preemtpions across groups
	- request merging across groups.

o Async queues are currently global and not per group. Allow preemption of
  an async queue if a sync queue in other group gets backlogged.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
220841906f blkio: Export disk time and sectors used by a group to user space
o Export disk time and sector used by a group to user space through cgroup
  interface.

o Also export a "dequeue" interface to cgroup which keeps track of how many
  a times a group was deleted from service tree. Helps in debugging.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
2868ef7b39 blkio: Some debugging aids for CFQ
o Some debugging aids for CFQ.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
b1c3576961 blkio: Take care of cgroup deletion and cfq group reference counting
o One can choose to change elevator or delete a cgroup. Implement group
  reference counting so that both elevator exit and cgroup deletion can
  take place gracefully.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Nauman Rafique <nauman@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
25fb5169d4 blkio: Dynamic cfq group creation based on cgroup tasks belongs to
o Determine the cgroup IO submitting task belongs to and create the cfq
  group if it does not exist already.

o Also link cfqq and associated cfq group.

o Currently all async IO is mapped to root group.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
dae739ebc4 blkio: Group time used accounting and workload context save restore
o This patch introduces the functionality to do the accounting of group time
  when a queue expires. This time used decides which is the group to go
  next.

o Also introduce the functionlity to save and restore the workload type
  context with-in group. It might happen that once we expire the cfq queue
  and group, a different group will schedule in and we will lose the context
  of the workload type. Hence save and restore it upon queue expiry.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
58ff82f34c blkio: Implement per cfq group latency target and busy queue avg
o So far we had 300ms soft target latency system wide. Now with the
  introduction of cfq groups, divide that latency by number of groups so
  that one can come up with group target latency which will be helpful
  in determining the workload slice with-in group and also the dynamic
  slice length of the cfq queue.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
25bc6b0776 blkio: Introduce per cfq group weights and vdisktime calculations
o Bring in the per cfq group weight and how vdisktime is calculated for the
  group. Also bring in the functionality of updating the min_vdisktime of
  the group service tree.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:52 +01:00
Vivek Goyal
31e4c28d95 blkio: Introduce blkio controller cgroup interface
o This is basic implementation of blkio controller cgroup interface. This is
  the common interface visible to user space and should be used by different
  IO control policies as we implement those.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:51 +01:00
Vivek Goyal
1fa8f6d68b blkio: Introduce the root service tree for cfq groups
o So far we just had one cfq_group in cfq_data. To create space for more than
  one cfq_group, we need to have a service tree of groups where all the groups
  can be queued if they have active cfq queues backlogged in these.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:51 +01:00
Vivek Goyal
f04a642463 blkio: Keep queue on service tree until we expire it
o Currently cfqq deletes a queue from service tree if it is empty (even if
  we might idle on the queue). This patch keeps the queue on service tree
  hence associated group remains on the service tree until we decide that
  we are not going to idle on the queue and expire it.

o This just helps in time accounting for queue/group and in implementation
  of rest of the patches.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:51 +01:00
Vivek Goyal
615f0259e6 blkio: Implement macro to traverse each service tree in group
o Implement a macro to traverse each service tree in the group. This avoids
  usage of double for loop and special condition for idle tree 4 times.

o Macro is little twisted because of special handling of idle class service
  tree.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:51 +01:00
Vivek Goyal
cdb16e8f73 blkio: Introduce the notion of cfq groups
o This patch introduce the notion of cfq groups. Soon we will can have multiple
  groups of different weights in the system.

o Various service trees (prioclass and workload type trees), will become per
  cfq group. So hierarchy looks as follows.

			cfq_groups
			   |
			workload type
			   |
		        cfq queue

o When an scheduling decision has to be taken, first we select the cfq group
  then workload with-in the group and then cfq queue with-in the workload
  type.

o This patch just makes various workload service tree per cfq group and
  introduce the function to be able to choose a group for scheduling.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:51 +01:00
Vivek Goyal
bf79193710 blkio: Set must_dispatch only if we decided to not dispatch the request
o must_dispatch flag should be set only if we decided not to run the queue
  and dispatch the request.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 19:28:51 +01:00
Shaohua Li
474b18ccc2 cfq-iosched: no dispatch limit for single queue
Since commit 2f5cb7381b, each queue can send
up to 4 * 4 requests if only one queue exists. I wonder why we have such limit.
Device supports tag can send more requests. For example, AHCI can send 31
requests. Test (direct aio randread) shows the limits reduce about 4% disk
thoughput.
On the other hand, since we send one request one time, if other queue
pop when current is sending more than cfq_quantum requests, current queue will
stop send requests soon after one request, so sounds there is no big latency.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 12:58:05 +01:00
Martin K. Petersen
98262f2762 block: Allow devices to indicate whether discarded blocks are zeroed
The discard ioctl is used by mkfs utilities to clear a block device
prior to putting metadata down.  However, not all devices return zeroed
blocks after a discard.  Some drives return stale data, potentially
containing old superblocks.  It is therefore important to know whether
discarded blocks are properly zeroed.

Both ATA and SCSI drives have configuration bits that indicate whether
zeroes are returned after a discard operation.  Implement a block level
interface that allows this information to be bubbled up the stack and
queried via a new block device ioctl.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-03 09:24:48 +01:00
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