12 Nov, 2014
1 commit
-
For cloned bio, bio->bi_vcnt can't be used at all, and we
have resort to bio_segments() to figure out how many
segment there are in the bio.Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
22 Oct, 2014
1 commit
-
The problem is introduced by commit 764f612c6c3c231b(blk-merge:
don't compute bi_phys_segments from bi_vcnt for cloned bio),
and merge is needed if number of current segment isn't less than
max segments.Strictly speaking, bio->bi_vcnt shouldn't be used here since
it may not be accurate in cases of both cloned bio or bio cloned
from, but bio_segments() is a bit expensive, and bi_vcnt is still
the biggest number, so the approach should work.Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
10 Oct, 2014
1 commit
-
It isn't correct to figure out req->bi_phys_segments from bio->bi_vcnt
if the bio is cloned.Signed-off-by: Ming Lei
Tested-by: Jeff Mahoney
Signed-off-by: Jens Axboe
27 Sep, 2014
1 commit
-
We'd occasionally merge requests with conflicting integrity flags.
Introduce a merge helper which checks that the requests have compatible
integrity payloads.Signed-off-by: Martin K. Petersen
Reviewed-by: Christoph Hellwig
Reviewed-by: Sagi Grimberg
Signed-off-by: Jens Axboe
03 Sep, 2014
1 commit
-
QUEUE_FLAG_NO_SG_MERGE is set at default for blk-mq devices,
so bio->bi_phys_segment computed may be bigger than
queue_max_segments(q) for blk-mq devices, then drivers will
fail to handle the case, for example, BUG_ON() in
virtio_queue_rq() can be triggerd for virtio-blk:https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1359146
This patch fixes the issue by ignoring the QUEUE_FLAG_NO_SG_MERGE
flag if the computed bio->bi_phys_segment is bigger than
queue_max_segments(q), and the regression is caused by commit
05f1dd53152173(block: add queue flag for disabling SG merging).Reported-by: Kick In
Tested-by: Chris J Arges
Signed-off-by: Ming Lei
Signed-off-by: Jens Axboe
25 Jun, 2014
1 commit
-
Another restriction inherited for NVMe - those devices don't support
SG lists that have "gaps" in them. Gaps refers to cases where the
previous SG entry doesn't end on a page boundary. For NVMe, all SG
entries must start at offset 0 (except the first) and end on a page
boundary (except the last).Signed-off-by: Jens Axboe
29 May, 2014
1 commit
-
If devices are not SG starved, we waste a lot of time potentially
collapsing SG segments. Enough that 1.5% of the CPU time goes
to this, at only 400K IOPS. Add a queue flag, QUEUE_FLAG_NO_SG_MERGE,
which just returns the number of vectors in a bio instead of looping
over all segments and checking for collapsible ones.Add a BLK_MQ_F_SG_MERGE flag so that drivers can opt-in on the sg
merging, if they so desire.Signed-off-by: Jens Axboe
08 Feb, 2014
1 commit
-
Immutable biovecs changed the way biovecs are interpreted - drivers no
longer use bi_vcnt, they have to go by bi_iter.bi_size (to allow for
using part of an existing segment without modifying it).This breaks with discards and write_same bios, since for those bi_size
has nothing to do with segments in the biovec. So for now, we need a
fairly gross hack - we fortunately know that there will never be more
than one segment for the entire request, so we can special case
discard/write_same.Signed-off-by: Kent Overstreet
Tested-by: Hugh Dickins
Signed-off-by: Jens Axboe
04 Dec, 2013
1 commit
-
The uninitialized_var() macro appears to not work on structs...
Get rid of it, and manually initialize instead.Signed-off-by: Kent Overstreet
Signed-off-by: Jens Axboe
27 Nov, 2013
1 commit
-
Signed-off-by: Kent Overstreet
Signed-off-by: Jens Axboe
24 Nov, 2013
3 commits
-
bio_iovec_idx() and __bio_iovec() don't have any valid uses anymore -
previous users have been converted to bio_iovec_iter() or other methods.__BVEC_END() has to go too - the bvec array can't be used directly for
the last biovec because we might only be using the first portion of it,
we have to iterate over the bvec array with bio_for_each_segment() which
checks against the current value of bi_iter.bi_size.Signed-off-by: Kent Overstreet
Cc: Jens Axboe -
More prep work for immutable biovecs - with immutable bvecs drivers
won't be able to use the biovec directly, they'll need to use helpers
that take into account bio->bi_iter.bi_bvec_done.This updates callers for the new usage without changing the
implementation yet.Signed-off-by: Kent Overstreet
Cc: Jens Axboe
Cc: Geert Uytterhoeven
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: "Ed L. Cashin"
Cc: Nick Piggin
Cc: Lars Ellenberg
Cc: Jiri Kosina
Cc: Paul Clements
Cc: Jim Paris
Cc: Geoff Levand
Cc: Yehuda Sadeh
Cc: Sage Weil
Cc: Alex Elder
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris
Cc: Philip Kelleher
Cc: Konrad Rzeszutek Wilk
Cc: Jeremy Fitzhardinge
Cc: Neil Brown
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: linux390@de.ibm.com
Cc: Nagalakshmi Nandigama
Cc: Sreekanth Reddy
Cc: support@lsi.com
Cc: "James E.J. Bottomley"
Cc: Greg Kroah-Hartman
Cc: Alexander Viro
Cc: Steven Whitehouse
Cc: Herton Ronaldo Krzesinski
Cc: Tejun Heo
Cc: Andrew Morton
Cc: Guo Chao
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Matthew Wilcox
Cc: Keith Busch
Cc: Stephen Hemminger
Cc: Quoc-Son Anh
Cc: Sebastian Ott
Cc: Nitin Gupta
Cc: Minchan Kim
Cc: Jerome Marchand
Cc: Seth Jennings
Cc: "Martin K. Petersen"
Cc: Mike Snitzer
Cc: Vivek Goyal
Cc: "Darrick J. Wong"
Cc: Chris Metcalf
Cc: Jan Kara
Cc: linux-m68k@lists.linux-m68k.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: drbd-user@lists.linbit.com
Cc: nbd-general@lists.sourceforge.net
Cc: cbe-oss-dev@lists.ozlabs.org
Cc: xen-devel@lists.xensource.com
Cc: virtualization@lists.linux-foundation.org
Cc: linux-raid@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: DL-MPTFusionLinux@lsi.com
Cc: linux-scsi@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: linux-fsdevel@vger.kernel.org
Cc: cluster-devel@redhat.com
Cc: linux-mm@kvack.org
Acked-by: Geoff Levand -
Immutable biovecs are going to require an explicit iterator. To
implement immutable bvecs, a later patch is going to add a bi_bvec_done
member to this struct; for now, this patch effectively just renames
things.Signed-off-by: Kent Overstreet
Cc: Jens Axboe
Cc: Geert Uytterhoeven
Cc: Benjamin Herrenschmidt
Cc: Paul Mackerras
Cc: "Ed L. Cashin"
Cc: Nick Piggin
Cc: Lars Ellenberg
Cc: Jiri Kosina
Cc: Matthew Wilcox
Cc: Geoff Levand
Cc: Yehuda Sadeh
Cc: Sage Weil
Cc: Alex Elder
Cc: ceph-devel@vger.kernel.org
Cc: Joshua Morris
Cc: Philip Kelleher
Cc: Rusty Russell
Cc: "Michael S. Tsirkin"
Cc: Konrad Rzeszutek Wilk
Cc: Jeremy Fitzhardinge
Cc: Neil Brown
Cc: Alasdair Kergon
Cc: Mike Snitzer
Cc: dm-devel@redhat.com
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: linux390@de.ibm.com
Cc: Boaz Harrosh
Cc: Benny Halevy
Cc: "James E.J. Bottomley"
Cc: Greg Kroah-Hartman
Cc: "Nicholas A. Bellinger"
Cc: Alexander Viro
Cc: Chris Mason
Cc: "Theodore Ts'o"
Cc: Andreas Dilger
Cc: Jaegeuk Kim
Cc: Steven Whitehouse
Cc: Dave Kleikamp
Cc: Joern Engel
Cc: Prasad Joshi
Cc: Trond Myklebust
Cc: KONISHI Ryusuke
Cc: Mark Fasheh
Cc: Joel Becker
Cc: Ben Myers
Cc: xfs@oss.sgi.com
Cc: Steven Rostedt
Cc: Frederic Weisbecker
Cc: Ingo Molnar
Cc: Len Brown
Cc: Pavel Machek
Cc: "Rafael J. Wysocki"
Cc: Herton Ronaldo Krzesinski
Cc: Ben Hutchings
Cc: Andrew Morton
Cc: Guo Chao
Cc: Tejun Heo
Cc: Asai Thambi S P
Cc: Selvan Mani
Cc: Sam Bradshaw
Cc: Wei Yongjun
Cc: "Roger Pau Monné"
Cc: Jan Beulich
Cc: Stefano Stabellini
Cc: Ian Campbell
Cc: Sebastian Ott
Cc: Christian Borntraeger
Cc: Minchan Kim
Cc: Jiang Liu
Cc: Nitin Gupta
Cc: Jerome Marchand
Cc: Joe Perches
Cc: Peng Tao
Cc: Andy Adamson
Cc: fanchaoting
Cc: Jie Liu
Cc: Sunil Mushran
Cc: "Martin K. Petersen"
Cc: Namjae Jeon
Cc: Pankaj Kumar
Cc: Dan Magenheimer
Cc: Mel Gorman 6
30 Oct, 2013
1 commit
-
For blk-mq, if a driver has requested per-request payload data
to carry command structures, they are stuffed into req->special.
For an old style request based driver, req->special is used
for the same purpose but indicates that a per-driver request
structure has been prepared for the request already. So for the
old style driver, we do not merge such requests.As most/all blk-mq drivers will use the payload feature, and
since we have no problem merging on these, make this check
dependent on whether it's a blk-mq enabled driver or not.Reported-by: Shaohua Li
Signed-off-by: Jens Axboe
20 Mar, 2013
1 commit
-
This is useful in places that recycle the same scatterlist multiple
times, and do not want to incur the cost of sg_init_table every
time in hot paths.Acked-by: Jens Axboe
Signed-off-by: Paolo Bonzini
Signed-off-by: Rusty Russell
20 Sep, 2012
3 commits
-
The WRITE SAME command supported on some SCSI devices allows the same
block to be efficiently replicated throughout a block range. Only a
single logical block is transferred from the host and the storage device
writes the same data to all blocks described by the I/O.This patch implements support for WRITE SAME in the block layer. The
blkdev_issue_write_same() function can be used by filesystems and block
drivers to replicate a buffer across a block range. This can be used to
efficiently initialize software RAID devices, etc.Signed-off-by: Martin K. Petersen
Acked-by: Mike Snitzer
Signed-off-by: Jens Axboe -
- blk_check_merge_flags() verifies that cmd_flags / bi_rw are
compatible. This function is called for both req-req and req-bio
merging.- blk_rq_get_max_sectors() and blk_queue_get_max_sectors() can be used
to query the maximum sector count for a given request or queue. The
calls will return the right value from the queue limits given the
type of command (RW, discard, write same, etc.)Signed-off-by: Martin K. Petersen
Acked-by: Mike Snitzer
Signed-off-by: Jens Axboe -
Remove special-casing of non-rw fs style requests (discard). The nomerge
flags are consolidated in blk_types.h, and rq_mergeable() and
bio_mergeable() have been modified to use them.bio_is_rw() is used in place of bio_has_data() a few places. This is
done to to distinguish true reads and writes from other fs type requests
that carry a payload (e.g. write same).Signed-off-by: Martin K. Petersen
Acked-by: Mike Snitzer
Signed-off-by: Jens Axboe
03 Aug, 2012
2 commits
-
Add a helper to map a bio to a scatterlist, modelled after
blk_rq_map_sg.This helper is useful for any driver that wants to create
a scatterlist from its ->make_request_fn method.Changes in v2:
- Use __blk_segment_map_sg to avoid duplicated code
- Add cocbook style function commentCc: Rusty Russell
Cc: Christoph Hellwig
Cc: Tejun Heo
Cc: Shaohua Li
Cc: "Michael S. Tsirkin"
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Signed-off-by: Christoph Hellwig
Signed-off-by: Minchan Kim
Signed-off-by: Asias He
Signed-off-by: Jens Axboe -
Split the mapping code in blk_rq_map_sg() to a helper
__blk_segment_map_sg(), so that other mapping function, e.g.
blk_bio_map_sg(), can share the code.Cc: Rusty Russell
Cc: Christoph Hellwig
Cc: Tejun Heo
Cc: Shaohua Li
Cc: "Michael S. Tsirkin"
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Suggested-by: Jens Axboe
Suggested-by: Tejun Heo
Signed-off-by: Asias He
Signed-off-by: Jens Axboe
08 Feb, 2012
1 commit
-
blk_rq_merge_ok() is the elevator-neutral part of merge eligibility
test. blk_try_merge() determines merge direction and expects the
caller to have tested elv_rq_merge_ok() previously.elv_rq_merge_ok() now wraps blk_rq_merge_ok() and then calls
elv_iosched_allow_merge(). elv_try_merge() is removed and the two
callers are updated to call elv_rq_merge_ok() explicitly followed by
blk_try_merge(). While at it, make rq_merge_ok() functions return
bool.This is to prepare for plug merge update and doesn't introduce any
behavior change.This is based on Jens' patch to skip elevator_allow_merge_fn() from
plug merge.Signed-off-by: Tejun Heo
LKML-Reference:
Original-patch-by: Jens Axboe
Signed-off-by: Jens Axboe
21 Mar, 2011
1 commit
-
One of the disadvantages of on-stack plugging is that we potentially
lose out on merging since all pending IO isn't always visible to
everybody. When we flush the on-stack plugs, right now we don't do
any checks to see if potential merge candidates could be utilized.Correct this by adding a new insert variant, ELEVATOR_INSERT_SORT_MERGE.
It works just ELEVATOR_INSERT_SORT, but first checks whether we can
merge with an existing request before doing the insertion (if we fail
merging).This fixes a regression with multiple processes issuing IO that
can be merged.Thanks to Shaohua Li for testing and fixing
an accounting bug.Signed-off-by: Jens Axboe
14 Jan, 2011
1 commit
-
* 'for-2.6.38/core' of git://git.kernel.dk/linux-2.6-block: (43 commits)
block: ensure that completion error gets properly traced
blktrace: add missing probe argument to block_bio_complete
block cfq: don't use atomic_t for cfq_group
block cfq: don't use atomic_t for cfq_queue
block: trace event block fix unassigned field
block: add internal hd part table references
block: fix accounting bug on cross partition merges
kref: add kref_test_and_get
bio-integrity: mark kintegrityd_wq highpri and CPU intensive
block: make kblockd_workqueue smarter
Revert "sd: implement sd_check_events()"
block: Clean up exit_io_context() source code.
Fix compile warnings due to missing removal of a 'ret' variable
fs/block: type signature of major_to_index(int) to major_to_index(unsigned)
block: convert !IS_ERR(p) && p to !IS_ERR_NOR_NULL(p)
cfq-iosched: don't check cfqg in choose_service_tree()
fs/splice: Pull buf->ops->confirm() from splice_from_pipe actors
cdrom: export cdrom_check_events()
sd: implement sd_check_events()
sr: implement sr_check_events()
...
07 Jan, 2011
1 commit
-
We can't use krefs since it's apparently restricted to very basic
reference counting.This reverts commit e4a683c8.
Signed-off-by: Jens Axboe
05 Jan, 2011
1 commit
-
/proc/diskstats would display a strange output as follows.
$ cat /proc/diskstats |grep sda
8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
~~~~~~~~~~
8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92
8 4 sda4 4 0 8 0 0 0 0 0 0 0 0
8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.The detailed root cause is as follows.
Assuming that there are two partition, sda1 and sda2.
1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
is 0 and sda2's one is 1.| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------2. A bio belongs to sda1 is issued and is merged into the request mentioned on
step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
from sda2 region to sda1 region. However the two partition's
hd_struct->in_flight are not changed.| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------3. The request is finished and blk_account_io_done() is called. In this case,
sda2's hd_struct->in_flight, not a sda1's one, is decremented.| hd_struct->in_flight
---------------------------
sda1 | -1
sda2 | 1
---------------------------The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.Also add a refcount to struct hd_struct to keep the partition in
memory as long as users exist. We use kref_test_and_get() to ensure
we don't add a reference to a partition which is going away.Signed-off-by: Jerome Marchand
Signed-off-by: Yasuaki Ishimatsu
Cc: stable@kernel.org
Signed-off-by: Jens Axboe
17 Dec, 2010
1 commit
-
When stacking devices, a request_queue is not always available. This
forced us to have a no_cluster flag in the queue_limits that could be
used as a carrier until the request_queue had been set up for a
metadevice.There were several problems with that approach. First of all it was up
to the stacking device to remember to set queue flag after stacking had
completed. Also, the queue flag and the queue limits had to be kept in
sync at all times. We got that wrong, which could lead to us issuing
commands that went beyond the max scatterlist limit set by the driver.The proper fix is to avoid having two flags for tracking the same thing.
We deprecate QUEUE_FLAG_CLUSTER and use the queue limit directly in the
block layer merging functions. The queue_limit 'no_cluster' is turned
into 'cluster' to avoid double negatives and to ease stacking.
Clustering defaults to being enabled as before. The queue flag logic is
removed from the stacking function, and explicitly setting the cluster
flag is no longer necessary in DM and MD.Reported-by: Ed Lin
Signed-off-by: Martin K. Petersen
Acked-by: Mike Snitzer
Cc: stable@kernel.org
Signed-off-by: Jens Axboe
25 Oct, 2010
1 commit
-
This reverts commit 7681bfeeccff5efa9eb29bf09249a3c400b15327.
Conflicts:
include/linux/genhd.h
It has numerous issues with the cleanup path and non-elevator
devices. Revert it for now so we can come up with a clean
version without rushing things.Signed-off-by: Jens Axboe
23 Oct, 2010
1 commit
-
* 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block: (39 commits)
cfq-iosched: Fix a gcc 4.5 warning and put some comments
block: Turn bvec_k{un,}map_irq() into static inline functions
block: fix accounting bug on cross partition merges
block: Make the integrity mapped property a bio flag
block: Fix double free in blk_integrity_unregister
block: Ensure physical block size is unsigned int
blkio-throttle: Fix possible multiplication overflow in iops calculations
blkio-throttle: limit max iops value to UINT_MAX
blkio-throttle: There is no need to convert jiffies to milli seconds
blkio-throttle: Fix link failure failure on i386
blkio: Recalculate the throttled bio dispatch time upon throttle limit change
blkio: Add root group to td->tg_list
blkio: deletion of a cgroup was causes oops
blkio: Do not export throttle files if CONFIG_BLK_DEV_THROTTLING=n
block: set the bounce_pfn to the actual DMA limit rather than to max memory
block: revert bad fix for memory hotplug causing bounces
Fix compile error in blk-exec.c for !CONFIG_DETECT_HUNG_TASK
block: set the bounce_pfn to the actual DMA limit rather than to max memory
block: Prevent hang_check firing during long I/O
cfq: improve fsync performance for small files
...Fix up trivial conflicts due to __rcu sparse annotation in include/linux/genhd.h
19 Oct, 2010
1 commit
-
/proc/diskstats would display a strange output as follows.
$ cat /proc/diskstats |grep sda
8 0 sda 90524 7579 102154 20464 0 0 0 0 0 14096 20089
8 1 sda1 19085 1352 21841 4209 0 0 0 0 4294967064 15689 4293424691
~~~~~~~~~~
8 2 sda2 71252 3624 74891 15950 0 0 0 0 232 23995 1562390
8 3 sda3 54 487 2188 92 0 0 0 0 0 88 92
8 4 sda4 4 0 8 0 0 0 0 0 0 0 0
8 5 sda5 81 2027 2130 138 0 0 0 0 0 87 137Its reason is the wrong way of accounting hd_struct->in_flight. When a bio is
merged into a request belongs to different partition by ELEVATOR_FRONT_MERGE.The detailed root cause is as follows.
Assuming that there are two partition, sda1 and sda2.
1. A request for sda2 is in request_queue. Hence sda1's hd_struct->in_flight
is 0 and sda2's one is 1.| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------2. A bio belongs to sda1 is issued and is merged into the request mentioned on
step1 by ELEVATOR_BACK_MERGE. The first sector of the request is changed
from sda2 region to sda1 region. However the two partition's
hd_struct->in_flight are not changed.| hd_struct->in_flight
---------------------------
sda1 | 0
sda2 | 1
---------------------------3. The request is finished and blk_account_io_done() is called. In this case,
sda2's hd_struct->in_flight, not a sda1's one, is decremented.| hd_struct->in_flight
---------------------------
sda1 | -1
sda2 | 1
---------------------------The patch fixes the problem by caching the partition lookup
inside the request structure, hence making sure that the increment
and decrement will always happen on the same partition struct. This
also speeds up IO with accounting enabled, since it cuts down on
the number of lookups we have to do.When reloading partition tables, quiesce IO to ensure that no
request references to the partition struct exists. When it is safe
to free the partition table, the IO for that device is restarted
again.Signed-off-by: Yasuaki Ishimatsu
Cc: stable@kernel.org
Signed-off-by: Jens Axboe
25 Sep, 2010
1 commit
-
Add logic to prevent two I/O requests being merged if
only one of them is a discard. Ditto secure discard.Without this fix, it is possible for write requests
to transform into discard requests. For example:Submit bio 1 to discard 8 sectors from sector n
Submit bio 2 to write 8 sectors from sector n + 16
Submit bio 3 to write 8 sectors from sector n + 8Bio 1 becomes request 1. Bio 2 becomes request 2.
Bio 3 is merged with request 2, and then subsequently
request 2 is merged with request 1 resulting in just
one I/O request which discards all 24 sectors.Signed-off-by: Adrian Hunter
(Moved the checks above the position checks /Jens)
Signed-off-by: Jens Axboe
11 Sep, 2010
1 commit
-
Some controllers have a hardware limit on the number of protection
information scatter-gather list segments they can handle.Introduce a max_integrity_segments limit in the block layer and provide
a new scsi_host_template setting that allows HBA drivers to provide a
value suitable for the hardware.Add support for honoring the integrity segment limit when merging both
bios and requests.Signed-off-by: Martin K. Petersen
Signed-off-by: Jens Axboe
08 Aug, 2010
3 commits
-
Just some dead code.
Signed-off-by: Andi Kleen
Signed-off-by: Andrew Morton
Signed-off-by: Jens Axboe -
Remove the current bio flags and reuse the request flags for the bio, too.
This allows to more easily trace the type of I/O from the filesystem
down to the block driver. There were two flags in the bio that were
missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've
renamed two request flags that had a superflous RW in them.Note that the flags are in bio.h despite having the REQ_ name - as
blkdev.h includes bio.h that is the only way to go for now.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe -
Remove all the trivial wrappers for the cmd_type and cmd_flags fields in
struct requests. This allows much easier grepping for different request
types instead of unwinding through macros.Signed-off-by: Christoph Hellwig
Signed-off-by: Jens Axboe
26 Feb, 2010
1 commit
-
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
Signed-off-by: Jens Axboe
07 Oct, 2009
1 commit
-
Commit a9327cac440be4d8333bba975cbbf76045096275 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 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 0f78ab9899e9d6acb09d5465def618704255963b
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
--
Signed-off-by: Jens Axboe
05 Oct, 2009
1 commit
-
This reverts commit a9327cac440be4d8333bba975cbbf76045096275.
Corrado Zoccolo 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 70,38Device: 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 2629219,87avg-cpu: %user %nice %system %iowait %steal %idle
2,72 0,00 0,74 0,00 0,00 96,53Device: 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 0,00 100,00avg-cpu: %user %nice %system %iowait %steal %idle
6,68 0,00 0,99 0,00 0,00 92,33Device: 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 0,00 100,00avg-cpu: %user %nice %system %iowait %steal %idle
4,40 0,00 0,73 1,47 0,00 93,40Device: 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 19,50 333,33 100,00Global 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:
[a9327cac440be4d8333bba975cbbf76045096275] 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
14 Sep, 2009
1 commit
-
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
Signed-off-by: Jens Axboe
11 Sep, 2009
2 commits
-
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
Cc: Niel Lambrechts
Cc: James Bottomley
Signed-off-by: Jens Axboe -
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
Cc: Niel Lambrechts
Signed-off-by: Jens Axboe