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2011-07-06Documentation: fix cgroup blkio throttle filenamesAndrea Righi
All the blkio.throttle.* file names are incorrectly reported without ".throttle" in the documentation. Fix it. Signed-off-by: Andrea Righi <andrea@betterlinux.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-15Documentation: fix cgroup typos and formattingJörg Sommer
Fix format and spelling. Signed-off-by: Jörg Sommer <joerg@alea.gnuu.de> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-15Documentation: update cgroupfs mount pointJörg Sommer
According to commit 676db4af0430 ("cgroupfs: create /sys/fs/cgroup to mount cgroupfs on") the canonical mountpoint for the cgroup filesystem is /sys/fs/cgroup. Hence, this should be used in the documentation. Signed-off-by: Jörg Sommer <joerg@alea.gnuu.de> Acked-by: Paul Menage <menage@google.com> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-03-08blk-cgroup: Lower minimum weight from 100 to 10.Justin TerAvest
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>
2011-03-01cfq-iosched: Always provide group isolation.Justin TerAvest
Effectively, make group_isolation=1 the default and remove the tunable. The setting group_isolation=0 was because by default we idle on sync-noidle tree and on fast devices, this can be very harmful for throughput. However, this problem can also be addressed by tuning slice_idle and possibly group_idle on faster storage devices. This change simplifies the CFQ code by removing the feature entirely. Signed-off-by: Justin TerAvest <teravest@google.com> Acked-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-11-15blk-cgroup: Allow creation of hierarchical cgroupsVivek Goyal
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: Vivek Goyal <vgoyal@redhat.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com> Reviewed-by: Ciju Rajan K <ciju@linux.vnet.ibm.com> Tested-by: Ciju Rajan K <ciju@linux.vnet.ibm.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-10-22Merge branch 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.37/core' of git://git.kernel.dk/linux-2.6-block: (39 commits) cfq-iosched: Fix a gcc 4.5 warning and put some comments block: Turn bvec_k{un,}map_irq() into static inline functions block: fix accounting bug on cross partition merges block: Make the integrity mapped property a bio flag block: Fix double free in blk_integrity_unregister block: Ensure physical block size is unsigned int blkio-throttle: Fix possible multiplication overflow in iops calculations blkio-throttle: limit max iops value to UINT_MAX blkio-throttle: There is no need to convert jiffies to milli seconds blkio-throttle: Fix link failure failure on i386 blkio: Recalculate the throttled bio dispatch time upon throttle limit change blkio: Add root group to td->tg_list blkio: deletion of a cgroup was causes oops blkio: Do not export throttle files if CONFIG_BLK_DEV_THROTTLING=n block: set the bounce_pfn to the actual DMA limit rather than to max memory block: revert bad fix for memory hotplug causing bounces Fix compile error in blk-exec.c for !CONFIG_DETECT_HUNG_TASK block: set the bounce_pfn to the actual DMA limit rather than to max memory block: Prevent hang_check firing during long I/O cfq: improve fsync performance for small files ... Fix up trivial conflicts due to __rcu sparse annotation in include/linux/genhd.h
2010-09-16blkio: Documentation UpdateVivek Goyal
o Documentation update Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-23cfq-iosched: Documentation help for new tunablesVivek Goyal
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>
2010-04-26blk-cgroup: config options re-arrangementVivek Goyal
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>
2010-04-13io-controller: Document for blkio.weight_deviceGui Jianfeng
Here is the document for blkio.weight_device 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>
2010-04-09blkio: Add more debug-only per-cgroup statsDivyesh Shah
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>
2010-04-09blkio: Add io_queued and avg_queue_size statsDivyesh Shah
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>
2010-04-09blkio: Add io_merged statDivyesh Shah
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>
2010-04-09blkio: Changes to IO controller additional stats patchesDivyesh Shah
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>
2009-12-03blkio: DocumentationVivek Goyal
Signed-off-by: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>