- 21 Jan, 2011 1 commit
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David Rientjes authored
The meaning of CONFIG_EMBEDDED has long since been obsoleted; the option is used to configure any non-standard kernel with a much larger scope than only small devices. This patch renames the option to CONFIG_EXPERT in init/Kconfig and fixes references to the option throughout the kernel. A new CONFIG_EMBEDDED option is added that automatically selects CONFIG_EXPERT when enabled and can be used in the future to isolate options that should only be considered for embedded systems (RISC architectures, SLOB, etc). Calling the option "EXPERT" more accurately represents its intention: only expert users who understand the impact of the configuration changes they are making should enable it. Reviewed-by:
Ingo Molnar <mingo@elte.hu> Acked-by:
David Woodhouse <david.woodhouse@intel.com> Signed-off-by:
David Rientjes <rientjes@google.com> Cc: Greg KH <gregkh@suse.de> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jens Axboe <axboe@kernel.dk> Cc: Arnd Bergmann <arn...
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- 14 Jan, 2011 2 commits
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Shaohua Li authored
If a queue is preempted before it gets slice assigned, the queue doesn't get compensation, which looks unfair. For such queue, we compensate it for a whole slice. Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Signed-off-by:
Jens Axboe <jaxboe@fusionio.com>
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Shaohua Li authored
I got this: fio-874 [007] 2157.724514: 8,32 m N cfq874 preempt fio-874 [007] 2157.724519: 8,32 m N cfq830 slice expired t=1 fio-874 [007] 2157.724520: 8,32 m N cfq830 sl_used=1 disp=0 charge=1 iops=0 sect=0 fio-874 [007] 2157.724521: 8,32 m N cfq830 set_active wl_prio:0 wl_type:0 fio-874 [007] 2157.724522: 8,32 m N cfq830 Not idling. st->count:1 cfq830 is an async queue, and preempted by a sync queue cfq874. But since we have cfqg->saved_workload_slice mechanism, the preempt is a nop. Looks currently our preempt is totally broken if the two queues are not from the same workload type. Below patch fixes it. This will might make async queue starvation, but it's what our old code does before cgroup is added. Signed-off-by:
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- 07 Jan, 2011 3 commits
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Shaohua Li authored
cfq_group->ref is used with queue_lock hold, the only exception is cfq_set_request, which looks like a bug to me, so ref doesn't need to be an atomic and atomic operation is slower. Signed-off-by:
Jeff Moyer <jmoyer@redhat.com> Acked-by:
Vivek Goyal <vgoyal@redhat.com> Signed-off-by:
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Shaohua Li authored
cfq_queue->ref is used with queue_lock hold, so ref doesn't need to be an atomic and atomic operation is slower. Signed-off-by:
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Jens Axboe authored
We can't use krefs since it's apparently restricted to very basic reference counting. This reverts commit e4a683c8 . Signed-off-by:
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- 05 Jan, 2011 1 commit
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Jerome Marchand authored
/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 87 137 Its 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 <jmarchan@redhat.com> Signed-off-by:
Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com> Cc: stable@kernel.org Signed-off-by:
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- 03 Jan, 2011 1 commit
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Tejun Heo authored
kblockd is used for unplugging and may affect IO latency and throughput and the max number of concurrent work items are bound by the number of block devices. Make it HIGHPRI workqueue w/ default max concurrency. Signed-off-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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- 21 Dec, 2010 1 commit
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Bart Van Assche authored
This patch fixes a spelling error in a source code comment and removes superfluous braces in the function exit_io_context(). Signed-off-by:
Bart Van Assche <bvanassche@acm.org> Cc: Jens Axboe <jaxboe@fusionio.com> Signed-off-by:
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- 17 Dec, 2010 5 commits
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Yang Zhang authored
The major/minor device numbers are always defined and used as `unsigned'. Signed-off-by:
Yang Zhang <kthreadd@gmail.com> Signed-off-by:
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Yang Zhang authored
Signed-off-by:
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Gui Jianfeng authored
When cfq_choose_cfqg() is called in select_queue(), there must be at least one backlogged CFQ queue waiting for dispatching, hence there must be at least one backlogged CFQ group on service tree. So we never call choose_service_tree() with cfqg == NULL. Signed-off-by:
Gui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by:
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Mike Snitzer authored
Implement blk_limits_max_hw_sectors() and make blk_queue_max_hw_sectors() a wrapper around it. DM needs this to avoid setting queue_limits' max_hw_sectors and max_sectors directly. dm_set_device_limits() now leverages blk_limits_max_hw_sectors() logic to establish the appropriate max_hw_sectors minimum (PAGE_SIZE). Fixes issue where DM was incorrectly setting max_sectors rather than max_hw_sectors (which caused dm_merge_bvec()'s max_hw_sectors check to be ineffective). Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Cc: stable@kernel.org Acked-by:
Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by:
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Martin K. Petersen authored
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...
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- 16 Dec, 2010 3 commits
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Tejun Heo authored
Currently, media presence polling for removeable block devices is done from userland. There are several issues with this. * Polling is done by periodically opening the device. For SCSI devices, the command sequence generated by such action involves a few different commands including TEST_UNIT_READY. This behavior, while perfectly legal, is different from Windows which only issues single command, GET_EVENT_STATUS_NOTIFICATION. Unfortunately, some ATAPI devices lock up after being periodically queried such command sequences. * There is no reliable and unintrusive way for a userland program to tell whether the target device is safe for media presence polling. For example, polling for media presence during an on-going burning session can make it fail. The polling program can avoid this by opening the device with O_EXCL but then it risks making a valid exclusive user of the device fail w/ -EBUSY. * Userland polling is unnecessarily heavy and in-kernel implementation is lighter and better coordinated (workqueue, timer slack). This patch implements framework for in-kernel disk event handling, which includes media presence polling. * bdops->check_events() is added, which supercedes ->media_changed(). It should check whether there's any pending event and return if so. Currently, two events are defined - DISK_EVENT_MEDIA_CHANGE and DISK_EVENT_EJECT_REQUEST. ->check_events() is guaranteed not to be called parallelly. * gendisk->events and ->async_events are added. These should be initialized by block driver before passing the device to add_disk(). The former contains the mask of all supported events and the latter the mask of all events which the device can report without polling. /sys/block/*/events[_async] export these to userland. * Kernel parameter block.events_dfl_poll_msecs controls the system polling interval (default is 0 which means disable) and /sys/block/*/events_poll_msecs control polling intervals for individual devices (default is -1 meaning use system setting). Note that if a device can report all supported events asynchronously and its polling interval isn't explicitly set, the device won't be polled regardless of the system polling interval. * If a device is opened exclusively with write access, event checking is automatically disabled until all write exclusive accesses are released. * There are event 'clearing' events. For example, both of currently defined events are cleared after the device has been successfully opened. This information is passed to ->check_events() callback using @clearing argument as a hint. * Event checking is always performed from system_nrt_wq and timer slack is set to 25% for polling. * Nothing changes for drivers which implement ->media_changed() but not ->check_events(). Going forward, all drivers will be converted to ->check_events() and ->media_change() will be dropped. Signed-off-by:
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Tejun Heo authored
There's no reason for register_disk() and del_gendisk() to be in fs/partitions/check.c. Move both to genhd.c. While at it, collapse unlink_gendisk(), which was artificially in a separate function due to genhd.c / check.c split, into del_gendisk(). Signed-off-by:
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Tejun Heo authored
There's no user of the facility. Kill it. Signed-off-by:
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- 13 Dec, 2010 1 commit
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Shaohua Li writes authored
If priority is changed, continuing to check workload_expires and service tree count of the previous workload does not make sense. We should always choose the workload with lowest key of new priority in such case. Signed-off-by:
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- 09 Dec, 2010 1 commit
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James Smart authored
This patch corrects an issue in bsg that results in a general protection fault if an LLD is removed while an application is using an open file handle to a bsg device, and the application issues an ioctl. The fault occurs because the class_dev is NULL, having been cleared in bsg_unregister_queue() when the driver was removed. With this patch, a check is made for the class_dev, and the application will receive ENXIO if the related object is gone. Signed-off-by:
Carl Lajeunesse <carl.lajeunesse@emulex.com> Signed-off-by:
James Smart <james.smart@emulex.com> Signed-off-by:
James Bottomley <James.Bottomley@suse.de>
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- 01 Dec, 2010 2 commits
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Vivek Goyal authored
o I was discussing what are the variable being updated without spin lock and why do we need barriers and Oleg pointed out that location of smp_rmb() should be between read of td->limits_changed and tg->limits_changed. This patch fixes it. o Following is one possible sequence of events. Say cpu0 is executing throtl_update_blkio_group_read_bps() and cpu1 is executing throtl_process_limit_change(). cpu0 cpu1 tg->limits_changed = true; smp_mb__before_atomic_inc(); atomic_inc(&td->limits_changed); if (!atomic_read(&td->limits_changed)) return; if (tg->limits_changed) do_something; If cpu0 has updated tg->limits_changed and td->limits_changed, we want to make sure that if update to td->limits_changed is visible on cpu1, then update t... -
Vivek Goyal authored
o During some testing I did following and noticed throttling stops working. - Put a very low limit on a cgroup, say 1 byte per second. - Start some reads, this will set slice_end to a very high value. - Change the limit to higher value say 1MB/s - Now IO unthrottles and finishes as expected. - Try to do the read again but IO is not limited to 1MB/s as expected. o What is happening. - Initially low value of limit sets slice_end to a very high value. - During updation of limit, slice_end is not being truncated. - Very high value of slice_end leads to keeping the existing slice valid for a very long time and new slice does not start. - tg_may_dispatch() is called in blk_throtle_bio(), and trim_slice() is not called in this path. So slice_start is some old value and practically we are able to do huge amount of IO. o There are many ways it can be fixed. I have fixed it by trying to adjust/cleanup slice_end in trim_slice(). Generally we extend slices if bio is big and can't be dispatched in one slice. After dispatch of bio, readjust the slice_end to make sure we don't end up with huge values. Signed-off-by:
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- 30 Nov, 2010 2 commits
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Gui Jianfeng authored
It's able to check whether a CFQ group on a service tree by checking "cfqg->rb_node". There's no need to maintain an extra flag here. Signed-off-by:
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Gui Jianfeng authored
When a cfq group is running, it won't be dequeued from service tree, so there's no need to store the active one in st->active. Just gid rid of it. Signed-off-by:
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- 29 Nov, 2010 1 commit
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Xiaotian Feng authored
commit 9284bcf4 checks for proper length of iov entries in blk_rq_map_user_iov(). But if the map is unaligned, kernel will break out the loop without checking for the proper length. So we need to check the proper length before the unalign check. Signed-off-by:
Xiaotian Feng <dfeng@redhat.com> Cc: stable@kernel.org Signed-off-by:
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- 17 Nov, 2010 1 commit
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Arnd Bergmann authored
The big kernel lock has been removed from all these files at some point, leaving only the #include. Remove this too as a cleanup. Signed-off-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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- 16 Nov, 2010 1 commit
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Mike Snitzer authored
Signed-off-by:
Kiyoshi Ueda <k-ueda@ct.jp.nec.com> Signed-off-by:
Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by:
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- 15 Nov, 2010 2 commits
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Vivek Goyal authored
o Allow hierarchical cgroup creation for blkio controller o Currently we disallow it as both the io controller policies (throttling as well as proportion bandwidth) do not support hierarhical accounting and control. But the flip side is that blkio controller can not be used with libvirt as libvirt creates a cgroup hierarchy deeper than 1 level. <top-level-cgroup-dir>/<controller>/libvirt/qemu/<virtual-machine-groups> o So this patch will allow creation of cgroup hierarhcy but at the backend everything will be treated as flat. So if somebody created a an hierarchy like as follows. root / \ test1 test2 | test3 CFQ and throttling will practically treat all groups at same level. pivot / | \ \ root test1 test2 test3 o Once we have actual support for hierarchical accounting and control then we can introduce another cgroup tunable file "blkio.use_hierarchy" which will be 0 by default but if user wants to enforce hierarhical control then it can be set to 1. This way there should not be any ABI problems down the line. o The only not so pretty part is introduction of extra file "use_hierarchy" down the line. Kame-san had mentioned that hierarhical accounting is expensive in memory controller hence they keep it off by default. I suspect same will be the case for IO controller also as for each IO completion we shall have to account IO through hierarchy up to the root. if yes, then it probably is not a very bad idea to introduce this extra file so that it will be used only when somebody needs it and some people might enable hierarchy only in part of the hierarchy. o This is how basically memory controller also uses "use_hierarhcy" and they also allowed creation of hierarchies when actual backend support was not available. Signed-off-by:
Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by:
Ciju Rajan K <ciju@linux.vnet.ibm.com> Tested-by:
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Vivek Goyal authored
o Currently we try to dispatch more READS and less WRITES (75%, 25%) in one dispatch round. ummy pointed out that there is a bug in max_nr_writes calculation. This patch fixes it. Reported-by:
ummy y <yummylln@yahoo.com.cn> Signed-off-by:
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- 13 Nov, 2010 1 commit
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Tejun Heo authored
Over time, block layer has accumulated a set of APIs dealing with bdev open, close, claim and release. * blkdev_get/put() are the primary open and close functions. * bd_claim/release() deal with exclusive open. * open/close_bdev_exclusive() are combination of open and claim and the other way around, respectively. * bd_link/unlink_disk_holder() to create and remove holder/slave symlinks. * open_by_devnum() wraps bdget() + blkdev_get(). The interface is a bit confusing and the decoupling of open and claim makes it impossible to properly guarantee exclusive access as in-kernel open + claim sequence can disturb the existing exclusive open even before the block layer knows the current open if for another exclusive access. Reorganize the interface such that, * blkdev_get() is extended to include exclusive access management. @holder argument is added and, if is @FMODE_EXCL specified, it will gain exclusive access atomically w.r.t. other exclusive accesses. * blkdev_put() is similarly extended. It now takes @mode argument and if @FMODE_EXCL is set, it releases an exclusive access. Also, when the last exclusive claim is released, the holder/slave symlinks are removed automatically. * bd_claim/release() and close_bdev_exclusive() are no longer necessary and either made static or removed. * bd_link_disk_holder() remains the same but bd_unlink_disk_holder() is no longer necessary and removed. * open_bdev_exclusive() becomes a simple wrapper around lookup_bdev() and blkdev_get(). It also has an unexpected extra bdev_read_only() test which probably should be moved into blkdev_get(). * open_by_devnum() is modified to take @holder argument and pass it to blkdev_get(). Most of bdev open/close operations are unified into blkdev_get/put() and most exclusive accesses are tested atomically at the open time (as it should). This cleans up code and removes some, both valid and invalid, but unnecessary all the same, corner cases. open_bdev_exclusive() and open_by_devnum() can use further cleanup - rename to blkdev_get_by_path() and blkdev_get_by_devt() and drop special features. Well, let's leave them for another day. Most conversions are straight-forward. drbd conversion is a bit more involved as there was some reordering, but the logic should stay the same. Signed-off-by:
Neil Brown <neilb@suse.de> Acked-by:
Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Acked-by:
Philipp Reisner <philipp.reisner@linbit.com> Cc: Peter Osterlund <petero2@telia.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Jan Kara <jack@suse.cz> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Alex Elder <aelder@sgi.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: dm-devel@redhat.com Cc: drbd-dev@lists.linbit.com Cc: Leo Chen <leochen@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: Chris Mason <chris.mason@oracle.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: Joern Engel <joern@logfs.org> Cc: reiserfs-devel@vger.kernel.org Cc: Alexander Viro <viro@zeniv.linux.org.uk>
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- 11 Nov, 2010 1 commit
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Jens Axboe authored
Reported-by:
Oleg Nesterov <oleg@redhat.com> Signed-off-by:
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- 10 Nov, 2010 5 commits
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Christoph Hellwig authored
REQ_HARDBARRIER is dead now, so remove the leftovers. What's left at this point is: - various checks inside the block layer. - sanity checks in bio based drivers. - now unused bio_empty_barrier helper. - Xen blockfront use of BLKIF_OP_WRITE_BARRIER - it's dead for a while, but Xen really needs to sort out it's barrier situaton. - setting of ordered tags in uas - dead code copied from old scsi drivers. - scsi different retry for barriers - it's dead and should have been removed when flushes were converted to FS requests. - blktrace handling of barriers - removed. Someone who knows blktrace better should add support for REQ_FLUSH and REQ_FUA, though. Signed-off-by:
Christoph Hellwig <hch@lst.de> Signed-off-by:
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Vasiliy Kulikov authored
Structure hd_geometry is copied to userland with 4 padding bytes between cylinders and start fields uninitialized on 64-bit platforms. It leads to leaking of contents of kernel stack memory. Currently there is no memset() in real implementations of getgeo() in drivers/block/, so it makes sense to have memset() in blkdev_ioctl(). Signed-off-by:
Vasiliy Kulikov <segooon@gmail.com> Signed-off-by:
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Mike Snitzer authored
Convert direct reads of an inode's i_size to using i_size_read(). i_size_{read,write} use a seqcount to protect reads from accessing incomple writes. Concurrent i_size_write()s require mutual exclussion to protect the seqcount that is used by i_size_{read,write}. But i_size_read() callers do not need to use additional locking. Signed-off-by:Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by:
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Jens Axboe authored
Reported-by:
Dan Rosenberg <drosenberg@vsecurity.com> Cc: stable@kernel.org Signed-off-by:
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Jens Axboe authored
Ensure that we pass down properly validated iov segments before calling into the mapping or copy functions. Reported-by:
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- 09 Nov, 2010 1 commit
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Shaohua Li authored
Vivek suggests we don't need schedule a dispatch when an idle queue becomes nonidle. And he is right, cfq_should_preempt already covers the logic. Signed-off-by:
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- 08 Nov, 2010 3 commits
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Shaohua Li authored
If a deep seek queue slowly deliver requests but disk is much faster, idle for the queue just wastes disk throughput. If the queue delevers all requests before half its slice is used, the patch disable idle for it. In my test, application delivers 32 requests one time, the disk can accept 128 requests at maxium and disk is fast. without the patch, the throughput is just around 30m/s, while with it, the speed is about 80m/s. The disk is a SSD, but is detected as a rotational disk. I can configure it as SSD, but I thought the deep seek queue logic should be fixed too, for example, considering a fast raid. Signed-off-by:
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Shaohua Li authored
A queue is idle at cfq_dispatch_requests(), but it gets noidle later. Unless other task explictly does unplug or all requests are drained, we will not deliever requests to the disk even cfq_arm_slice_timer doesn't make the queue idle. For example, cfq_should_idle() returns true because of service_tree->count == 1, and then other queues are added. Note, I didn't see obvious performance impacts so far with the patch, but just thought this could be a problem. Signed-off-by:
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Shaohua Li authored
Some functions should return boolean. Signed-off-by:
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- 01 Nov, 2010 1 commit
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Uwe Kleine-König authored
"gadget", "through", "command", "maintain", "maintain", "controller", "address", "between", "initiali[zs]e", "instead", "function", "select", "already", "equal", "access", "management", "hierarchy", "registration", "interest", "relative", "memory", "offset", "already", Signed-off-by:
Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by:
Jiri Kosina <jkosina@suse.cz>
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