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* cfq-iosched: Make IO merge related stats per cpuVivek Goyal2011-05-231-2/+2
| | | | | | | | Make BLKIO_STAT_MERGED per cpu hence gettring rid of need of taking blkg->stats_lock. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: Make 64bit per cpu stats safe on 32bit archVivek Goyal2011-05-201-0/+2
| | | | | | | | | Some of the stats are 64bit and updation will be non atomic on 32bit architecture. Use sequence counters on 32bit arch to make reading of stats safe. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-throttle: Make dispatch stats per cpuVivek Goyal2011-05-201-6/+21
| | | | | | | | | | | | | | | Currently we take blkg_stat lock for even updating the stats. So even if a group has no throttling rules (common case for root group), we end up taking blkg_lock, for updating the stats. Make dispatch stats per cpu so that these can be updated without taking blkg lock. If cpu goes offline, these stats simply disappear. No protection has been provided for that yet. Do we really need anything for that? Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: move some fields of unaccounted_time file under right config optionVivek Goyal2011-05-201-3/+4
| | | | | | | | cgroup unaccounted_time file is created only if CONFIG_DEBUG_BLK_CGROUP=y. there are some fields which are out side this config option. Fix that. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-throttle: Use task_subsys_state() to determine a task's blkio_cgroupVivek Goyal2011-05-161-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currentlly we first map the task to cgroup and then cgroup to blkio_cgroup. There is a more direct way to get to blkio_cgroup from task using task_subsys_state(). Use that. The real reason for the fix is that it also avoids a race in generic cgroup code. During remount/umount rebind_subsystems() is called and it can do following with and rcu protection. cgrp->subsys[i] = NULL; That means if somebody got hold of cgroup under rcu and then it tried to do cgroup->subsys[] to get to blkio_cgroup, it would get NULL which is wrong. I was running into this race condition with ltp running on a upstream derived kernel and that lead to crash. So ideally we should also fix cgroup generic code to wait for rcu grace period before setting pointer to NULL. Li Zefan is not very keen on introducing synchronize_wait() as he thinks it will slow down moun/remount/umount operations. So for the time being atleast fix the kernel crash by taking a more direct route to blkio_cgroup. One tester had reported a crash while running LTP on a derived kernel and with this fix crash is no more seen while the test has been running for over 6 days. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: Add unaccounted time to timeslice_used.Justin TerAvest2011-03-121-2/+10
| | | | | | | | | | | | There are two kind of times that tasks are not charged for: the first seek and the extra time slice used over the allocated timeslice. Both of these exported as a new unaccounted_time stat. I think it would be good to have this reported in 'time' as well, but that is probably a separate discussion. Signed-off-by: Justin TerAvest <teravest@google.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: Lower minimum weight from 100 to 10.Justin TerAvest2011-03-081-1/+1
| | | | | | | | | | We've found that we still get good, useful isolation at weights this low. I'd like to adjust the minimum so that any other changes can take these values into account. Signed-off-by: Justin TerAvest <teravest@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkio-throttle: limit max iops value to UINT_MAXVivek Goyal2010-10-011-0/+3
| | | | | | | - Limit max iops value to UINT_MAX and return error to user if value is more than that instead of accepting bigger values and truncating implicitly. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blkio: Recalculate the throttled bio dispatch time upon throttle limit changeVivek Goyal2010-10-011-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | o Currently any cgroup throttle limit changes are processed asynchronousy and the change does not take affect till a new bio is dispatched from same group. o It might happen that a user sets a redicuously low limit on throttling. Say 1 bytes per second on reads. In such cases simple operations like mount a disk can wait for a very long time. o Once bio is throttled, there is no easy way to come out of that wait even if user increases the read limit later. o This patch fixes it. Now if a user changes the cgroup limits, we recalculate the bio dispatch time according to new limits. o Can't take queueu lock under blkcg_lock, hence after the change I wake up the dispatch thread again which recalculates the time. So there are some variables being synchronized across two threads without lock and I had to make use of barriers. Hoping I have used barriers correctly. Any review of memory barrier code especially will help. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: cgroup changes for IOPS limit supportVivek Goyal2010-09-161-0/+13
| | | | | | | o cgroup changes for IOPS throttling rules. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: Introduce cgroup changes for throttling policyVivek Goyal2010-09-161-1/+29
| | | | | | | | | o cgroup chagnes for throttle policy. o Introduces READ and WRITE bytes per second throttling rules. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: Prepare the base for supporting more than one IO control policiesVivek Goyal2010-09-161-2/+34
| | | | | | | | | | | | | o This patch prepares the base for introducing new IO control policies. Currently all the code is written knowing there is only one policy and that is proportional bandwidth. Creating infrastructure for newer policies to come in. o Also there were many functions which were generated using macro. It was very confusing. Got rid of those. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* blk-cgroup: config options re-arrangementVivek Goyal2010-04-261-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes few usability and configurability issues. o All the cgroup based controller options are configurable from "Genral Setup/Control Group Support/" menu. blkio is the only exception. Hence make this option visible in above menu and make it configurable from there to bring it inline with rest of the cgroup based controllers. o Get rid of CONFIG_DEBUG_CFQ_IOSCHED. This option currently does two things. - Enable printing of cgroup paths in blktrace - Enables CONFIG_DEBUG_BLK_CGROUP, which in turn displays additional stat files in cgroup. If we are using group scheduling, blktrace data is of not really much use if cgroup information is not present. To get this data, currently one has to also enable CONFIG_DEBUG_CFQ_IOSCHED, which in turn brings the overhead of all the additional debug stat files which is not desired. Hence, this patch moves printing of cgroup paths under CONFIG_CFQ_GROUP_IOSCHED. This allows us to get rid of CONFIG_DEBUG_CFQ_IOSCHED completely. Now all the debug stat files are controlled only by CONFIG_DEBUG_BLK_CGROUP which can be enabled through config menu. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Divyesh Shah <dpshah@google.com> Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Fix another BUG_ON() crash due to cfqq movement across groupsVivek Goyal2010-04-261-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | o Once in a while, I was hitting a BUG_ON() in blkio code. empty_time was assuming that upon slice expiry, group can't be marked empty already (except forced dispatch). But this assumption is broken if cfqq can move (group_isolation=0) across groups after receiving a request. I think most likely in this case we got a request in a cfqq and accounted the rq in one group, later while adding the cfqq to tree, we moved the queue to a different group which was already marked empty and after dispatch from slice we found group already marked empty and raised alarm. This patch does not error out if group is already marked empty. This can introduce some empty_time stat error only in case of group_isolation=0. This is better than crashing. In case of group_isolation=1 we should still get same stats as before this patch. [ 222.308546] ------------[ cut here ]------------ [ 222.309311] kernel BUG at block/blk-cgroup.c:236! [ 222.309311] invalid opcode: 0000 [#1] SMP [ 222.309311] last sysfs file: /sys/devices/virtual/block/dm-3/queue/scheduler [ 222.309311] CPU 1 [ 222.309311] Modules linked in: dm_round_robin dm_multipath qla2xxx scsi_transport_fc dm_zero dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan] [ 222.309311] [ 222.309311] Pid: 4780, comm: fio Not tainted 2.6.34-rc4-blkio-config #68 0A98h/HP xw8600 Workstation [ 222.309311] RIP: 0010:[<ffffffff8121ad88>] [<ffffffff8121ad88>] blkiocg_set_start_empty_time+0x50/0x83 [ 222.309311] RSP: 0018:ffff8800ba6e79f8 EFLAGS: 00010002 [ 222.309311] RAX: 0000000000000082 RBX: ffff8800a13b7990 RCX: ffff8800a13b7808 [ 222.309311] RDX: 0000000000002121 RSI: 0000000000000082 RDI: ffff8800a13b7a30 [ 222.309311] RBP: ffff8800ba6e7a18 R08: 0000000000000000 R09: 0000000000000001 [ 222.309311] R10: 000000000002f8c8 R11: ffff8800ba6e7ad8 R12: ffff8800a13b78ff [ 222.309311] R13: ffff8800a13b7990 R14: 0000000000000001 R15: ffff8800a13b7808 [ 222.309311] FS: 00007f3beec476f0(0000) GS:ffff880001e40000(0000) knlGS:0000000000000000 [ 222.309311] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 222.309311] CR2: 000000000040e7f0 CR3: 00000000a12d5000 CR4: 00000000000006e0 [ 222.309311] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 222.309311] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 [ 222.309311] Process fio (pid: 4780, threadinfo ffff8800ba6e6000, task ffff8800b3d6bf00) [ 222.309311] Stack: [ 222.309311] 0000000000000001 ffff8800bab17a48 ffff8800bab17a48 ffff8800a13b7800 [ 222.309311] <0> ffff8800ba6e7a68 ffffffff8121da35 ffff880000000001 00ff8800ba5c5698 [ 222.309311] <0> ffff8800ba6e7a68 ffff8800a13b7800 0000000000000000 ffff8800bab17a48 [ 222.309311] Call Trace: [ 222.309311] [<ffffffff8121da35>] __cfq_slice_expired+0x2af/0x3ec [ 222.309311] [<ffffffff8121fd7b>] cfq_dispatch_requests+0x2c8/0x8e8 [ 222.309311] [<ffffffff8120f1cd>] ? spin_unlock_irqrestore+0xe/0x10 [ 222.309311] [<ffffffff8120fb1a>] ? blk_insert_cloned_request+0x70/0x7b [ 222.309311] [<ffffffff81210461>] blk_peek_request+0x191/0x1a7 [ 222.309311] [<ffffffffa0002799>] dm_request_fn+0x38/0x14c [dm_mod] [ 222.309311] [<ffffffff810ae61f>] ? sync_page_killable+0x0/0x35 [ 222.309311] [<ffffffff81210fd4>] __generic_unplug_device+0x32/0x37 [ 222.309311] [<ffffffff81211274>] generic_unplug_device+0x2e/0x3c [ 222.309311] [<ffffffffa00011a6>] dm_unplug_all+0x42/0x5b [dm_mod] [ 222.309311] [<ffffffff8120ca37>] blk_unplug+0x29/0x2d [ 222.309311] [<ffffffff8120ca4d>] blk_backing_dev_unplug+0x12/0x14 [ 222.309311] [<ffffffff81109a7a>] block_sync_page+0x35/0x39 [ 222.309311] [<ffffffff810ae616>] sync_page+0x41/0x4a [ 222.309311] [<ffffffff810ae62d>] sync_page_killable+0xe/0x35 [ 222.309311] [<ffffffff8158aa59>] __wait_on_bit_lock+0x46/0x8f [ 222.309311] [<ffffffff810ae4f5>] __lock_page_killable+0x66/0x6d [ 222.309311] [<ffffffff81056f9c>] ? wake_bit_function+0x0/0x33 [ 222.309311] [<ffffffff810ae528>] lock_page_killable+0x2c/0x2e [ 222.309311] [<ffffffff810afbc5>] generic_file_aio_read+0x361/0x4f0 [ 222.309311] [<ffffffff810ea044>] do_sync_read+0xcb/0x108 [ 222.309311] [<ffffffff811e42f7>] ? security_file_permission+0x16/0x18 [ 222.309311] [<ffffffff810ea6ab>] vfs_read+0xab/0x108 [ 222.309311] [<ffffffff810ea7c8>] sys_read+0x4a/0x6e [ 222.309311] [<ffffffff81002b5b>] system_call_fastpath+0x16/0x1b [ 222.309311] Code: 58 01 00 00 00 48 89 c6 75 0a 48 83 bb 60 01 00 00 00 74 09 48 8d bb a0 00 00 00 eb 35 41 fe cc 74 0d f6 83 c0 01 00 00 04 74 04 <0f> 0b eb fe 48 89 75 e8 e8 be e0 de ff 66 83 8b c0 01 00 00 04 [ 222.309311] RIP [<ffffffff8121ad88>] blkiocg_set_start_empty_time+0x50/0x83 [ 222.309311] RSP <ffff8800ba6e79f8> [ 222.309311] ---[ end trace 32b4f71dffc15712 ]--- Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Acked-by: Divyesh Shah <dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Initialize blkg->stats_lock for the root cfqg tooDivyesh Shah2010-04-161-2/+0
| | | | | | | | This fixes the lockdep warning reported by Gui Jianfeng. Signed-off-by: Divyesh Shah <dpshah@google.com> Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* block: Update to io-controller statsDivyesh Shah2010-04-131-6/+6
| | | | | | | | | | | | | | | | | | | Changelog from v1: o Call blkiocg_update_idle_time_stats() at cfq_rq_enqueued() instead of at dispatch time. Changelog from original patchset: (in response to Vivek Goyal's comments) o group blkiocg_update_blkio_group_dequeue_stats() with other DEBUG functions o rename blkiocg_update_set_active_queue_stats() to blkiocg_update_avg_queue_size_stats() o s/request/io/ in blkiocg_update_request_add_stats() and blkiocg_update_request_remove_stats() o Call cfq_del_timer() at request dispatch() instead of blkiocg_update_idle_time_stats() Signed-off-by: Divyesh Shah<dpshah@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* io-controller: Add a new interface "weight_device" for IO-ControllerGui Jianfeng2010-04-131-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, IO Controller makes use of blkio.weight to assign weight for all devices. Here a new user interface "blkio.weight_device" is introduced to assign different weights for different devices. blkio.weight becomes the default value for devices which are not configured by "blkio.weight_device" You can use the following format to assigned specific weight for a given device: #echo "major:minor weight" > blkio.weight_device major:minor represents device number. And you can remove weight for a given device as following: #echo "major:minor 0" > blkio.weight_device V1->V2 changes: - use user interface "weight_device" instead of "policy" suggested by Vivek - rename some struct suggested by Vivek - rebase to 2.6-block "for-linus" branch - remove an useless list_empty check pointed out by Li Zefan - some trivial typo fix V2->V3 changes: - Move policy_*_node() functions up to get rid of forward declarations - rename related functions by adding prefix "blkio_" Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Add more debug-only per-cgroup statsDivyesh Shah2010-04-091-0/+54
| | | | | | | | | | | | | | | | | | | | | | | | | | | 1) group_wait_time - This is the amount of time the cgroup had to wait to get a timeslice for one of its queues from when it became busy, i.e., went from 0 to 1 request queued. This is different from the io_wait_time which is the cumulative total of the amount of time spent by each IO in that cgroup waiting in the scheduler queue. This stat is a great way to find out any jobs in the fleet that are being starved or waiting for longer than what is expected (due to an IO controller bug or any other issue). 2) empty_time - This is the amount of time a cgroup spends w/o any pending requests. This stat is useful when a job does not seem to be able to use its assigned disk share by helping check if that is happening due to an IO controller bug or because the job is not submitting enough IOs. 3) idle_time - This is the amount of time spent by the IO scheduler idling for a given cgroup in anticipation of a better request than the exising ones from other queues/cgroups. All these stats are recorded using start and stop events. When reading these stats, we do not add the delta between the current time and the last start time if we're between the start and stop events. We avoid doing this to make sure that these numbers are always monotonically increasing when read. Since we're using sched_clock() which may use the tsc as its source, it may induce some inconsistency (due to tsc resync across cpus) if we included the current delta. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Add io_queued and avg_queue_size statsDivyesh Shah2010-04-091-1/+19
| | | | | | | | | | | | | These stats are useful for getting a feel for the queue depth of the cgroup, i.e., how filled up its queues are at a given instant and over the existence of the cgroup. This ability is useful when debugging problems in the wild as it helps understand the application's IO pattern w/o having to read through the userspace code (coz its tedious or just not available) or w/o the ability to run blktrace (since you may not have root access and/or not want to disturb performance). Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Add io_merged statDivyesh Shah2010-04-091-1/+7
| | | | | | | | | | | | | | | | This includes both the number of bios merged into requests belonging to this cgroup as well as the number of requests merged together. In the past, we've observed different merging behavior across upstream kernels, some by design some actual bugs. This stat helps a lot in debugging such problems when applications report decreased throughput with a new kernel version. This needed adding an extra elevator function to capture bios being merged as I did not want to pollute elevator code with blkiocg knowledge and hence needed the accounting invocation to come from CFQ. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Changes to IO controller additional stats patchesDivyesh Shah2010-04-091-25/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | that include some minor fixes and addresses all comments. Changelog: (most based on Vivek Goyal's comments) o renamed blkiocg_reset_write to blkiocg_reset_stats o more clarification in the documentation on io_service_time and io_wait_time o Initialize blkg->stats_lock o rename io_add_stat to blkio_add_stat and declare it static o use bool for direction and sync o derive direction and sync info from existing rq methods o use 12 for major:minor string length o define io_service_time better to cover the NCQ case o add a separate reset_stats interface o make the indexed stats a 2d array to simplify macro and function pointer code o blkio.time now exports in jiffies as before o Added stats description in patch description and Documentation/cgroup/blkio-controller.txt o Prefix all stats functions with blkio and make them static as applicable o replace IO_TYPE_MAX with IO_TYPE_TOTAL o Moved #define constant to top of blk-cgroup.c o Pass dev_t around instead of char * o Add note to documentation file about resetting stats o use BLK_CGROUP_MODULE in addition to BLK_CGROUP config option in #ifdef statements o Avoid struct request specific knowledge in blk-cgroup. blk-cgroup.h now has rq_direction() and rq_sync() functions which are used by CFQ and when using io-controller at a higher level, bio_* functions can be added. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Increment the blkio cgroup stats for real nowDivyesh Shah2010-04-021-3/+11
| | | | | | | | | | We also add start_time_ns and io_start_time_ns fields to struct request here to record the time when a request is created and when it is dispatched to device. We use ns uints here as ms and jiffies are not very useful for non-rotational media. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Add io controller stats likeDivyesh Shah2010-04-021-8/+31
| | | | | | | | | | | | | | - io_service_time - io_wait_time - io_serviced - io_service_bytes These stats are accumulated per operation type helping us to distinguish between read and write, and sync and async IO. This patch does not increment any of these stats. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Remove per-cfqq nr_sectors as we'll be passingDivyesh Shah2010-04-021-4/+2
| | | | | | | | | that info at request dispatch with other stats now. This patch removes the existing support for accounting sectors for a blkio_group. This will be added back differently in the next two patches. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* cgroups: blkio subsystem as moduleBen Blum2010-03-121-2/+8
| | | | | | | | | | | | | | | | | | Modify the Block I/O cgroup subsystem to be able to be built as a module. As the CFQ disk scheduler optionally depends on blk-cgroup, config options in block/Kconfig, block/Kconfig.iosched, and block/blk-cgroup.h are enhanced to support the new module dependency. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Paul Menage <menage@google.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cfq: Remove useless css reference getGui Jianfeng2010-02-261-3/+0
| | | | | | | | | | | There's no need to take css reference here, for the caller has already called rcu_read_lock() to prevent cgroup from being removed. Signed-off-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Implement dynamic io controlling policy registrationVivek Goyal2009-12-041-0/+24
| | | | | | | | | | | | | | | | | | | | o One of the goals of block IO controller is that it should be able to support mulitple io control policies, some of which be operational at higher level in storage hierarchy. o To begin with, we had one io controlling policy implemented by CFQ, and I hard coded the CFQ functions called by blkio. This created issues when CFQ is compiled as module. o This patch implements a basic dynamic io controlling policy registration functionality in blkio. This is similar to elevator functionality where ioschedulers register the functions dynamically. o Now in future, when more IO controlling policies are implemented, these can dynakically register with block IO controller. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Export some symbols from blkio as its user CFQ can be a moduleVivek Goyal2009-12-041-0/+3
| | | | | | | | | o blkio controller is inside the kernel and cfq makes use of interfaces exported by blkio. CFQ can be a module too, hence export symbols used by CFQ. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* cfq-iosched: fix compile problem with !CONFIG_CGROUPJens Axboe2009-12-031-0/+10
| | | | Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Export disk time and sectors used by a group to user spaceVivek Goyal2009-12-031-2/+20
| | | | | | | | | | | o Export disk time and sector used by a group to user space through cgroup interface. o Also export a "dequeue" interface to cgroup which keeps track of how many a times a group was deleted from service tree. Helps in debugging. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Some debugging aids for CFQVivek Goyal2009-12-031-0/+13
| | | | | | | o Some debugging aids for CFQ. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Take care of cgroup deletion and cfq group reference countingVivek Goyal2009-12-031-0/+1
| | | | | | | | | | o One can choose to change elevator or delete a cgroup. Implement group reference counting so that both elevator exit and cgroup deletion can take place gracefully. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Nauman Rafique <nauman@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
* blkio: Introduce blkio controller cgroup interfaceVivek Goyal2009-12-031-0/+58
o This is basic implementation of blkio controller cgroup interface. This is the common interface visible to user space and should be used by different IO control policies as we implement those. Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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