- 09 Oct, 2008 40 commits
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Jens Axboe authored
Somewhat incomplete, as we do allow merges of requests and bios that have different completion CPUs given. This is done on the assumption that a larger IO is still more beneficial than CPU locality. Signed-off-by:Jens Axboe <jens.axboe@oracle.com>
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Jens Axboe authored
This patch adds support for controlling the IO completion CPU of either all requests on a queue, or on a per-request basis. We export a sysfs variable (rq_affinity) which, if set, migrates completions of requests to the CPU that originally submitted it. A bio helper (bio_set_completion_cpu()) is also added, so that queuers can ask for completion on that specific CPU. In testing, this has been show to cut the system time by as much as 20-40% on synthetic workloads where CPU affinity is desired. This requires a little help from the architecture, so it'll only work as designed for archs that are using the new generic smp helper infrastructure. Signed-off-by: -
Jens Axboe authored
Preparatory patch for checking queuing affinity. Signed-off-by: -
Jens Axboe authored
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Jens Axboe authored
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Tejun Heo authored
Now that disk and partition handlings are mostly unified, it's easy to allow disk to have extended device number. This patch makes add_disk() use extended device number if disk->minors is zero. Both sd and ide-disk are updated to use this. * sd_format_disk_name() is implemented which can generically determine the drive name. This removes disk number restriction stemming from limited device names. * If sd index goes over SD_MAX_DISKS (which can be increased now BTW), sd simply doesn't initialize minors letting block layer choose extended device number. * If CONFIG_DEBUG_EXT_DEVT is set, both sd and ide-disk always set minors to 0 and use extended device numbers. Signed-off-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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Tejun Heo authored
With previous changes, it's meaningless to limit the number of partitions. Replace @ext_minors with GENHD_FL_EXT_DEVT such that setting the flag allows the disk to have maximum number of allowed partitions (only limited by the number of entries in parsed_partitions as determined by MAX_PART constant). This kills not-too-pretty alloc_disk_ext[_node]() functions and makes @minors parameter to alloc_disk[_node]() unnecessary. The parameter is left alone to avoid disturbing the users. Signed-off-by:
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Tejun Heo authored
disk->__part used to be statically allocated to the maximum possible number of partitions. This patch makes partition array allocation dynamic. The added overhead is minimal as only real change is one memory dereference changed to RCU one. This saves both a bit of memory and cpu cycles iterating through unoccupied slots and makes increasing partition limit easier. Signed-off-by:
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Tejun Heo authored
Move stats related fields - stamp, in_flight, dkstats - from disk to part0 and unify stat handling such that... * part_stat_*() now updates part0 together if the specified partition is not part0. ie. part_stat_*() are now essentially all_stat_*(). * {disk|all}_stat_*() are gone. * part_round_stats() is updated similary. It handles part0 stats automatically and disk_round_stats() is killed. * part_{inc|dec}_in_fligh() is implemented which automatically updates part0 stats for parts other than part0. * disk_map_sector_rcu() is updated to return part0 if no part matches. Combined with the above changes, this makes NULL special case handling in callers unnecessary. * Separate stats show code paths for disk are collapsed into part stats show code paths. * Rename disk_stat_lock/unlock() to part_stat_lock/unlock() While at it, reposition stat handling macros a bit and add missing parentheses around macro parameters. Signed-off-by: -
Tejun Heo authored
GENHD_FL_FAIL for disk is what make_it_fail is for parts. Kill it and use part0->make_it_fail. Sysfs node handling is unified too. Signed-off-by:
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Tejun Heo authored
Till now, bdev->bd_part is set only if the bdev was for parts other than part0. This patch makes bdev->bd_part always set so that code paths don't have to differenciate common handling. Signed-off-by:
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Tejun Heo authored
Move disk->holder_dir to part0->holder_dir. Kill now mostly superflous bdev_get_holder(). While at it, kill superflous kobject_get/put() around holder_dir, slave_dir and cmd_filter creation and collapse disk_sysfs_add_subdirs() into register_disk(). These serve no purpose but obfuscating the code. Signed-off-by:
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Tejun Heo authored
Move disk->policy to part0->policy. Implement and use get_disk_ro(). Signed-off-by:
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Tejun Heo authored
Now that capacity and __dev are moved to part0, part0 and others can share the same method. Signed-off-by:
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Tejun Heo authored
Move disk->__dev to part0->__dev. This simplifies bdget_disk() and lookup_devt() and allows common sysfs attributes to be unified. part_to_disk() is updated to handle part0 -> disk. Updated to include a fix from Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>, he writes: "part0 is a "special" partition and doesn't need to have capacity set - this fixes regression caused by "block: move __dev from disk to part0" commit." Signed-off-by:
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Tejun Heo authored
Move disk->capacity to part0->nr_sects and convert all users who directly accessed the field to use {get|set}_capacity(). This is done early to allow the __dev field to be moved. Signed-off-by: -
Tejun Heo authored
genhd and partition code handled disk and partitions separately. All information about the whole disk was in struct genhd and partitions in struct hd_struct. However, the whole disk (part0) and other partitions have a lot in common and the data structures end up having good number of common fields and thus separate code paths doing the same thing. Also, the partition array was indexed by partno - 1 which gets pretty confusing at times. This patch introduces partition 0 and makes the partition array indexed by partno. Following patches will unify the handling of disk and parts piece-by-piece. This patch also implements disk_partitionable() which tests whether a disk is partitionable. With coming dynamic partition array change, the most common usage of disk_max_parts() will be testing whether a disk is partitionable and the number of max partitions will become much less important. Signed-off-by:
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Tejun Heo authored
Implement {disk|part}_to_dev() and use them to access generic device instead of directly dereferencing {disk|part}->dev. To make sure no user is left behind, rename generic devices fields to __dev. This is in preparation of unifying partition 0 handling with other partitions. Signed-off-by: -
Tejun Heo authored
Extended devt introduces non-contiguos device numbers. This patch implements a debug option which forces most devt allocations to be from the extended area and spreads them out. This is enabled by default if DEBUG_KERNEL is set and achieves... 1. Detects code paths in kernel or userland which expect predetermined consecutive device numbers. 2. When something goes wrong, avoid corruption as adding to the minor of earlier partition won't lead to the wrong but valid device. Signed-off-by:
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Tejun Heo authored
Update sd and ide-disk such that they can take advantage of extended minors. ide-disk already has 64 minors per device and currently doesn't use extended minors although after this patch it can be turned on by simply tweaking constants. sd only had 16 minors per device causing problems on certain peculiar configurations. This patch lifts the restriction and enables it to use upto 64 minors. Signed-off-by:
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Tejun Heo authored
With extended minors and the soon-to-follow debug feature, large minor numbers for block devices will be common. This patch does the followings to make printouts pretty. * Adapt print formats such that large minors don't break the formatting. * For extended MAJ:MIN, %02x%02x for MAJ:MIN used in printk_all_partitions() doesn't cut it anymore. Update it such that %03x:%05x is used if either MAJ or MIN doesn't fit in %02x. * Implement ext_range sysfs attribute which shows total minors the device can use including both conventional minor space and the extended one. Signed-off-by:
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Tejun Heo authored
Implement extended device numbers. A block driver can tell block layer that it wants to use extended device numbers. After the usual minor space is used up, block layer automatically allocates devt's from EXT_BLOCK_MAJOR. Currently only one major number is allocated for this but as the allocation is strictly on-demand, ~1mil minor space under it should suffice unless the system actually has more than ~1mil partitions and if that ever happens adding more majors to the extended devt area is easy. Due to internal implementation issues, the first partition can't be allocated on the extended area. In other words, genhd->minors should at least be 1. This limitation will be lifted by later changes. Signed-off-by:
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Tejun Heo authored
There are two variants of stat functions - ones prefixed with double underbars which don't care about preemption and ones without which disable preemption before manipulating per-cpu counters. It's unclear whether the underbarred ones assume that preemtion is disabled on entry as some callers don't do that. This patch unifies diskstats access by implementing disk_stat_lock() and disk_stat_unlock() which take care of both RCU (for partition access) and preemption (for per-cpu counter access). diskstats access should always be enclosed between the two functions. As such, there's no need for the versions which disables preemption. They're removed and double underbars ones are renamed to drop the underbars. As an extra argument is added, there's no danger of using the old version unconverted. disk_stat_lock() uses get_cpu() and returns the cpu index and all diskstat functions which access per-cpu counters now has @cpu argument to help RT. This change adds RCU or preemption operations at some places but also collapses several preemption ops into one at others. Overall, the performance difference should be negligible as all involved ops are very lightweight per-cpu ones. Signed-off-by:
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Tejun Heo authored
disk->part[] is protected by its matching bdev's lock. However, non-critical accesses like collecting stats and printing out sysfs and proc information used to be performed without any locking. As partitions can come and go dynamically, partitions can go away underneath those non-critical accesses. As some of those accesses are writes, this theoretically can lead to silent corruption. This patch fixes the race by using RCU for the partition array and dev reference counter to hold partitions. * Rename disk->part[] to disk->__part[] to make sure no one outside genhd layer proper accesses it directly. * Use RCU for disk->__part[] dereferencing. * Implement disk_{get|put}_part() which can be used to get and put partitions from gendisk respectively. * Iterators are implemented to help iterate through all partitions safely. * Functions which require RCU readlock are marked with _rcu suffix. * Use disk_put_part() in __blkdev_put() instead of directly putting the contained kobject. Signed-off-by: -
Tejun Heo authored
* Implement disk_devt() and part_devt() and use them to directly access devt instead of computing it from ->major and ->first_minor. Note that all references to ->major and ->first_minor outside of block layer is used to determine devt of the disk (the part0) and as ->major and ->first_minor will continue to represent devt for the disk, converting these users aren't strictly necessary. However, convert them for consistency. * Implement disk_max_parts() to avoid directly deferencing genhd->minors. * Update bdget_disk() such that it doesn't assume consecutive minor space. * Move devt computation from register_disk() to add_disk() and make it the only one (all other usages use the initially determined value). These changes clean up the code and will help disk->part dereference fix and extended block device numbers. Signed-off-by:
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Tejun Heo authored
In hd_struct, @partno is used to denote partition number and a number of other places use @part to denote hd_struct. Functions use @part and @index instead. This causes confusion and makes it difficult to use consistent variable names for hd_struct. Always use @partno if a variable represents partition number. Also, print out functions use @f or @part for seq_file argument. Use @seqf uniformly instead. Signed-off-by:
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Tejun Heo authored
This patch makes the following misc updates in preparation for disk->part dereference fix and extended block devt support. * implment part_to_disk() * fix comment about gendisk->part indexing * rename get_part() to disk_map_sector() * don't use n which is always zero while printing disk information in diskstats_show() Signed-off-by:
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Tejun Heo authored
d805dda4 tried to fix error case handling in add_partition() but had a few problems. * disk->part[] entry is set early and left dangling if operation fails. * Once device initialized, the last put_device() is responsible for freeing all the resources. The failure path freed part_stats and p regardless of put_device() causing double free. * holders subdir holds reference to the disk device, so failure path should remove it to release resources properly which was missing. This patch fixes the above problems and while at it move partition slot busy check into add_partition() for completeness and inlines holders subdirectory creation. Using separate function for it just obfuscates the code. Signed-off-by:
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Tejun Heo authored
delete_partition() was noop for zero length partition. As the addition code allows creating zero lenght partition and deletion is assumed to always succeed, this causes memory leak for zero length partitions. Allow zero length partitions to end their meaningless lives. While at it, allow deleting zero lenght partition via BLKPG_DEL_PARTITION ioctl too. Signed-off-by:
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Tejun Heo authored
Recent block_class iteration updates 5c6f35c5..27f30251 converted all class device iteration to class_for_each_device() and class_find_device(), which are correct but pain in the ass to use. This pach converts them to newly introduced class_dev_iterator so that they can use more natural control structures instead of separate callbacks and struct to pass parameters to them. This results in smaller and easier code. This patch also restores the original behavior of not printing header in /proc/partitions if there's no partition to print. This is trivial but still user-visible behavior. Signed-off-by:
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Tejun Heo authored
block_class_lock protects major_names array and bdev_map and doesn't have anything to do with block class devices. Don't grab them while iterating over block class devices. Signed-off-by:
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Tejun Heo authored
Recent block_class iteration updates 5c6f35c5..27f30251 broke partition info printouts. * printk_all_partitions(): Partition print out stops when it meets a partition hole. Partition printing inner loop should continue instead of exiting on empty partition slot. * /proc/partitions and /proc/diskstats: If all information can't be read in single read(), the information is truncated. This is because find_start() doesn't actually update the counter containing the initial seek. It runs to the end and ends up always reporting EOF on the second read. This patch fixes both problems. Signed-off-by:
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Tejun Heo authored
Iterating over entries using callback usually isn't too fun especially when the entry being iterated over can't be manipulated freely. This patch converts class->p->class_devices to klist and implements class device iterator so that the users can freely build their own control structure. The users are also free to call back into class code without worrying about locking. class_for_each_device() and class_find_device() are converted to use the new iterators, so their users don't have to worry about locking anymore either. Note: This depends on klist-dont-iterate-over-deleted-entries patch because class_intf->add/remove_dev() depends on proper synchronization with device removal. Signed-off-by:
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Tejun Heo authored
A klist entry is kept on the list till all its current iterations are finished; however, a new iteration after deletion also iterates over deleted entries as long as their reference count stays above zero. This causes problems for cases where there are users which iterate over the list while synchronized against list manipulations and natuarally expect already deleted entries to not show up during iteration. This patch implements dead flag which gets set on deletion so that iteration can skip already deleted entries. The dead flag piggy backs on the lowest bit of knode->n_klist and only visible to klist implementation proper. While at it, drop klist_iter->i_head as it's redundant and doesn't offer anything in semantics or performance wise as klist_iter->i_klist is dereferenced on every iteration anyway. Signed-off-by:
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Randy Dunlap authored
Add some block/ source files to the kernel-api docbook. Fix kernel-doc notation in them as needed. Fix changed function parameter names. Fix typos/spellos. In comments, change REQ_SPECIAL to REQ_TYPE_SPECIAL and REQ_BLOCK_PC to REQ_TYPE_BLOCK_PC. Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
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Jens Axboe authored
raid5 can overflow with more than 255 stripes, and we can increase it to an int for free on both 32 and 64-bit archs due to the padding. Signed-off-by: -
Jens Axboe authored
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Mikulas Patocka authored
Remove hw_segments field from struct bio and struct request. Without virtual merge accounting they have no purpose. Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
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Mikulas Patocka authored
Remove virtual merge accounting. Signed-off-by:
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Aaron Carroll authored
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:
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