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* iosched: prevent aliased requests from starving other I/OJeff Moyer2011-06-021-3/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Hi, Jens, If you recall, I posted an RFC patch for this back in July of last year: http://lkml.org/lkml/2010/7/13/279 The basic problem is that a process can issue a never-ending stream of async direct I/Os to the same sector on a device, thus starving out other I/O in the system (due to the way the alias handling works in both cfq and deadline). The solution I proposed back then was to start dispatching from the fifo after a certain number of aliases had been dispatched. Vivek asked why we had to treat aliases differently at all, and I never had a good answer. So, I put together a simple patch which allows aliases to be added to the rb tree (it adds them to the right, though that doesn't matter as the order isn't guaranteed anyway). I think this is the preferred solution, as it doesn't break up time slices in CFQ or batches in deadline. I've tested it, and it does solve the starvation issue. Let me know what you think. Cheers, Jeff Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* block: remove per-queue pluggingJens Axboe2011-03-101-9/+0
| | | | | | | | 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>
* block: convert to pos and nr_sectors accessorsTejun Heo2009-05-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With recent cleanups, there is no place where low level driver directly manipulates request fields. This means that the 'hard' request fields always equal the !hard fields. Convert all rq->sectors, nr_sectors and current_nr_sectors references to accessors. While at it, drop superflous blk_rq_pos() < 0 test in swim.c. [ Impact: use pos and nr_sectors accessors ] Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Tested-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Grant Likely <grant.likely@secretlab.ca> Tested-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Adrian McMenamin <adrian@mcmen.demon.co.uk> Acked-by: Mike Miller <mike.miller@hp.com> Cc: James Bottomley <James.Bottomley@HansenPartnership.com> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Borislav Petkov <petkovbb@googlemail.com> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Eric Moore <Eric.Moore@lsi.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Paul Clements <paul.clements@steeleye.com> Cc: Tim Waugh <tim@cyberelk.net> Cc: Jeff Garzik <jgarzik@pobox.com> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Alex Dubov <oakad@yahoo.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Dario Ballabio <ballabio_dario@emc.com> Cc: David S. Miller <davem@davemloft.net> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: unsik Kim <donari75@gmail.com> Cc: Laurent Vivier <Laurent@lvivier.info> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: get rid of elevator_t typedefJens Axboe2008-12-291-3/+3
| | | | | | Just use struct elevator_queue everywhere instead. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* deadline-iosched: non-functional fixesAaron Carroll2008-10-091-13/+13
| | | | | | | | | | | * convert goto to simpler while loop; * use rq_end_sector() instead of computing manually; * fix false comments; * remove spurious whitespace; * convert rq_rb_root macro to an inline function. Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* deadline-iosched: allow non-sequential batchingAaron Carroll2008-10-091-11/+3
| | | | | | | | | | | Deadline currently only batches sector-contiguous requests, so except for a few circumstances (e.g. requests in a single direction), it is essentially first come first served. This is bad for throughput, so change it to CSCAN, which means requests in a batch do not need to be sequential and are issued in increasing sector order. Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: let elv_register() return voidAdrian Bunk2007-12-181-1/+3
| | | | | | | | | elv_register() always returns 0, and there isn't anything it does where it should return an error (the only error condition is so grave that it's handled with a BUG_ON). Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Deadline iosched: Fix batching fairnessAaron Carroll2007-11-021-14/+7
| | | | | | | | | | | | | After switching data directions, deadline always starts the next batch from the lowest-sector request. This gives excessive deadline expiries and large latency and throughput disparity between high- and low-sector requests; an order of magnitude in some tests. This patch changes the batching behaviour so new batches start from the request whose expiry is earliest. Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Deadline iosched: Reset batch for ordered requestsAaron Carroll2007-11-021-3/+3
| | | | | | | | | | | | | The deadline I/O scheduler does not reset the batch count when starting a new batch at a higher-sectored request. This means the second and subsequent batch in the same data direction will never exceed a single request in size whenever higher-sectored requests are pending. This patch gives new batches in the same data direction as old ones their full quota of requests by resetting the batch count. Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* Deadline iosched: Factor out finding latter requesAaron Carroll2007-11-021-11/+17
| | | | | | | | Factor finding the next request in sector-sorted order into a function deadline_latter_request. Signed-off-by: Aaron Carroll <aaronc@gelato.unsw.edu.au> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [BLOCK] Get rid of request_queue_t typedefJens Axboe2007-07-241-9/+9
| | | | | | | | | 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>
* Slab allocators: Replace explicit zeroing with __GFP_ZEROChristoph Lameter2007-07-171-2/+1
| | | | | | | | | | | | | kmalloc_node() and kmem_cache_alloc_node() were not available in a zeroing variant in the past. But with __GFP_ZERO it is possible now to do zeroing while allocating. Use __GFP_ZERO to remove the explicit clearing of memory via memset whereever we can. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [BLOCK] Cleanup unused variable passingJens Axboe2006-12-011-1/+1
| | | | | | | | - ->init_queue() does not need the elevator passed in - ->put_request() is a hot path and need not have the queue passed in - cfq_update_io_seektime() does not need cfqd passed in Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* [PATCH] Update axboe@suse.de email addressJens Axboe2006-09-301-1/+1
| | | | | | | As people often look for the copyright in files to see who to mail, update the link to a neutral one. Signed-off-by: Jens Axboe <axboe@kernel.dk>
* [PATCH] deadline-iosched: remove elevator private drq request typeJens Axboe2006-09-301-142/+52
| | | | | | | | A big win, we now save an allocation/free on each request! With the previous rb/hash abstractions, we can just reuse queuelist/donelist for the FIFO data and be done with it. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] deadline-iosched: migrate to using the elevator rb functionsJens Axboe2006-09-301-136/+34
| | | | | | This removes the rbtree handling from deadline. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] elevator: move the backmerging logic into the elevator coreJens Axboe2006-09-301-126/+2
| | | | | | | | | | | Right now, every IO scheduler implements its own backmerging (except for noop, which does no merging). That results in duplicated code for essentially the same operation, which is never a good thing. This patch moves the backmerging out of the io schedulers and into the elevator core. We save 1.6kb of text and as a bonus get backmerging for noop as well. Win-win! Signed-off-by: Jens Axboe <axboe@suse.de>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-301-1/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] rbtree: support functions used by the io schedulersJens Axboe2006-06-231-8/+5
| | | | | | | They all duplicate macros to check for empty root and/or node, and clearing a node. So put those in rbtree.h. Signed-off-by: Jens Axboe <axboe@suse.de>
* [PATCH] iosched: use hlist for request hashtableAkinobu Mita2006-06-231-23/+16
| | | | | | | | | | | | Use hlist instead of list_head for request hashtable in deadline-iosched and as-iosched. It also can remove the flag to know hashed or unhashed. Signed-off-by: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Jens Axboe <axboe@suse.de> block/as-iosched.c | 45 +++++++++++++++++++-------------------------- block/deadline-iosched.c | 39 ++++++++++++++++----------------------- 2 files changed, 35 insertions(+), 49 deletions(-)
* Merge git://git.infradead.org/~dwmw2/rbtree-2.6Linus Torvalds2006-06-201-3/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.infradead.org/~dwmw2/rbtree-2.6: [RBTREE] Switch rb_colour() et al to en_US spelling of 'color' for consistency Update UML kernel/physmem.c to use rb_parent() accessor macro [RBTREE] Update hrtimers to use rb_parent() accessor macro. [RBTREE] Add explicit alignment to sizeof(long) for struct rb_node. [RBTREE] Merge colour and parent fields of struct rb_node. [RBTREE] Remove dead code in rb_erase() [RBTREE] Update JFFS2 to use rb_parent() accessor macro. [RBTREE] Update eventpoll.c to use rb_parent() accessor macro. [RBTREE] Update key.c to use rb_parent() accessor macro. [RBTREE] Update ext3 to use rb_parent() accessor macro. [RBTREE] Change rbtree off-tree marking in I/O schedulers. [RBTREE] Add accessor macros for colour and parent fields of rb_node
| * [RBTREE] Change rbtree off-tree marking in I/O schedulers.David Woodhouse2006-04-211-3/+2
| | | | | | | | | | | | | | | | | | They were abusing the rb_color field to mark nodes which weren't currently on the tree. Fix that to use the same method as eventpoll did -- setting the parent pointer to point back to itself. And use the appropriate accessor macros for setting and reading the parent. Signed-off-by: David Woodhouse <dwmw2@infradead.org>
* | [PATCH] elevator switching raceJens Axboe2006-06-081-7/+6
|/ | | | | | | | | | | | | | | | | | | | There's a race between shutting down one io scheduler and firing up the next, in which a new io could enter and cause the io scheduler to be invoked with bad or NULL data. To fix this, we need to maintain the queue lock for a bit longer. Unfortunately we cannot do that, since the elevator init requires to be run without the lock held. This isn't easily fixable, without also changing the mempool API. So split the initialization into two parts, and alloc-init operation and an attach operation. Then we can preallocate the io scheduler and related structures, and run the attach inside the lock after we detach the old one. This patch has survived 30 minutes of 1 second io scheduler switching with a very busy io load. Signed-off-by: Jens Axboe <axboe@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix rmmod problems with elevator attributes, clean them upAl Viro2006-03-181-43/+21
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* [PATCH] elevator_t lifetime rules and sysfs fixesAl Viro2006-03-181-52/+12
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* [BLOCK] mark some block/ variables consArjan van de Ven2006-01-061-4/+4
| | | | | | | | | the patch below marks various read-only variables in block/* as const, so that gcc can optimize the use of them; eg gcc will replace the use by the value directly now and will even remove the memory usage of these. Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Jens Axboe <axboe@suse.de>
* [BLOCK] new block/ directory comment tidyCoywolf Qi Hunt2005-11-181-2/+0
| | | | | | | | Some leftover comments referring to drivers/block that are now block/. They don't add any information we don't already have, so kill them. Signed-off-by: Coywolf Qi Hunt <qiyong@fc-cn.com> Signed-off-by: Jens Axboe <axboe@suse.de>
* [BLOCK] Move all core block layer code to new block/ directoryJens Axboe2005-11-041-0/+878
drivers/block/ is right now a mix of core and driver parts. Lets move the core parts to a new top level directory. Al will move the fs/ related block parts to block/ next. Signed-off-by: Jens Axboe <axboe@suse.de>
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