This patch updates the documentation of the ROW
I/O scheduler.
Change-Id: I6a996a3852fe39976381f99c07588558f1945034
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
This patch adds the implementation of a new scheduling algorithm - ROW.
The policy of this algorithm is to prioritize READ requests over WRITE
as much as possible without starving the WRITE requests.
Change-Id: I4ed52ea21d43b0e7c0769b2599779a3d3869c519
Signed-off-by: Tatyana Brokhman <tlinder@codeaurora.org>
The test scheduler allows testing a block device by dispatching
specific requests according to the test case and declare PASS/FAIL
according to the requests completion error code
Change-Id: Ief91f9fed6e3c3c75627d27264d5252ea14f10ad
Signed-off-by: Maya Erez <merez@codeaurora.org>
Remove 'as' for as is no longer supported, and we can not use
'elevator=as' any more.
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are numerous broken references to Documentation files (in other
Documentation files, in comments, etc.). These broken references are
caused by typo's in the references, and by renames or removals of the
Documentation files. Some broken references are simply odd.
Fix these broken references, sometimes by dropping the irrelevant text
they were part of.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
There are always questions about why CFQ is idling on various conditions.
Recent ones is Christoph asking again why to idle on REQ_NOIDLE. His
assertion is that XFS is relying more and more on workqueues and is
concerned that CFQ idling on IO from every workqueue will impact
XFS badly.
So he suggested that I add some more documentation about CFQ idling
and that can provide more clarity on the topic and also gives an
opprotunity to poke a hole in theory and lead to improvements.
So here is my attempt at that. Any comments are welcome.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Some systems benefit from completions always being steered to the strict
requester cpu rather than the looser "per-socket" steering that
blk_cpu_to_group() attempts by default. This is because the first
CPU in the group mask ends up being completely overloaded with work,
while the others (including the original submitter) has power left
to spare.
Allow the strict mode to be set by writing '2' to the sysfs control
file. This is identical to the scheme used for the nomerges file,
where '2' is a more aggressive setting than just being turned on.
echo 2 > /sys/block/<bdev>/queue/rq_affinity
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Roland Dreier <roland@purestorage.com>
Tested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Remove anticipatory block I/O scheduler info from Documentation/
since the code has been deleted.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Reported-by: "Robert P. J. Day" <rpjday@crashcourse.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Some documentation to provide help with tunables.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
- It looks incorrect to use blk_rq_map_sg with pci_map_page here about
DMA mappings. dma_map_sg?
- better to use dma_map_page instead of pci_map_page.
http://marc.info/?l=linux-kernel&m=126596737604808&w=2
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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>
It seems that Documentation/DMA-mapping.txt was supposed to be renamed
to Documentation/PCI/PCI-DMA-mapping.txt.
Signed-off-by: Kusanagi Kouichi <slash@ac.auone-net.jp>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 492af6350a removed
the AS IO scheduler, so remove its documentation too.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andre Noll <maan@systemlinux.org>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
We do per-device plugging, get rid of any references to tq_disk as that
has been dead since 2.6.5 or so.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
These lines appear in this file twice - removed one occurrence.
Signed-off-by: Avishay Traeger <avishay@il.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
biodoc.txt mentions that elevator functions marked with * are mandatory, but
no function is marked with *. Mark the 3 functions which should be
implemented by any io scheduler.
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Move DMA-mapping.txt to Documentation/PCI/.
DMA-mapping.txt was supposed to be moved from Documentation/ to
Documentation/PCI/. The 00-INDEX files in those two directories
were updated, along with a few other text files, but the file
itself somehow escaped being moved, so move it and update more
text files and source files with its new location.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The drivers/block/ll_rw_block.c has been split and organized in the block/
directory, and also drivers/block/elevator.c has been moved to the block/
directory. Update Documentation/block/biodoc.txt accordingly
Signed-off-by: Nikanth Karthikesan <knikanth@suse.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* 'docs' of git://git.lwn.net/linux-2.6:
Document panic_on_unrecovered_nmi sysctl
Add a reference to paper to SubmittingPatches
Add kerneldoc documentation for new printk format extensions
Remove videobook.tmpl
doc: Test-by?
Add the development process document
Documentation/block/data-integrity.txt: Fix section numbers
Update the description of fifo_batch to match the current implementation,
and include a description of how to tune it.
Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
as-iosched.txt:
o Changed IO scheduler selection text to a reference to the
switching-sched.txt file.
o Fixed typo: 'for up time...' -> 'for up to...'
o Added short description of the est_time file.
deadline-iosched.txt:
o Changed IO scheduler selection text to a reference to the
switching-sched.txt file.
o Removed references to non-existent seek-cost and stream_unit.
o Fixed typo: 'write_starved' -> 'writes_starved'
switching-sched.txt:
o Added in boot-time argument to set the default IO scheduler. (From
as-iosched.txt)
o Added in sysfs mount instructions. (From deadline-iosched.txt)
Signed-off-by: Alan D. Brunelle <Alan.Brunelle@hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
The newer glibc does not allow system calls to be made via _syscallN()
wrapper. They have to be made through syscall(). The ionice code used
the older interface. Correcting it to use syscall.
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Every usage of rq_for_each_bio wraps a usage of
bio_for_each_segment, so these can be combined into
rq_for_each_segment.
We define "struct req_iterator" to hold the 'bio' and 'index' that
are needed for the double iteration.
Signed-off-by: Neil Brown <neilb@suse.de>
Various compile fixes by me...
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Allow user space to determine if a disk supports Asynchronous Notification of
media changes. This is done by adding a new sysfs file "capability_flags",
which is documented in (insert file name). This sysfs file will export all
disk capabilities flags to user space. We also define a new flag to define
the media change notification capability.
Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix various typos in kernel docs and Kconfigs, 2.6.21-rc4.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Documentation update, adding references to CFQ scheduler and to another
document about selecting IO Schedulers.
Signed-off-by: Filipe Lautert <filipe@icewall.org>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes typos in various Documentation txts. The patch addresses some
misc words.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch fixes typos in various Documentation txts. The patch addresses some
+words starting with the letters 'U-Z'.
Looks like I made it through the alphabet...just in time to start over again
+too! Maybe I can fit more profound fixes into the next round...? Time will
+tell. :)
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Remove many duplicated words under Documentation/ and do other small
cleanups.
Examples:
"and and" --> "and"
"in in" --> "in"
"the the" --> "the"
"the the" --> "to the"
...
Signed-off-by: Paolo Ornati <ornati@fastwebnet.it>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letter 'S'.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Alan Cox <alan@redhat.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letters 'Q'-'R'.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
This patch fixes typos in various Documentation txts. The patch addresses
some words starting with the letters 'N'-'P'.
Signed-off-by: Matt LaPlante <kernel1@cyberdogtech.com>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Tatyana Brokhman
Maya Erez
Wang Sheng-Hui
Paul Bolle
Vivek Goyal
Dan Williams
Lucas De Marchi
Jens Axboe
Randy Dunlap
Christoph Hellwig
Nick Piggin
FUJITA Tomonori
Jens Axboe
Alan D. Brunelle
Kusanagi Kouichi
Andre Noll
Matt LaPlante
vibi sreenivasan
Avishay Traeger
Nikanth Karthikesan
Linus Torvalds
Alberto Bertogli
Aaron Carroll
Martin K. Petersen
Robert P. J. Day
Rob Landley
Dhaval Giani
NeilBrown
Geert Uytterhoeven
Kristen Carlson Accardi
Filipe
Paolo Ornati