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2019-06-01blk-mq: Document the blk_mq_hw_queue_to_node() argumentsBart Van Assche1-1/+5
Document the meaning of the blk_mq_hw_queue_to_node() arguments. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-06-01blk-mq: Fix spelling in a source code commentBart Van Assche1-2/+2
Change one occurrence of 'performace' into 'performance'. Cc: Max Gurtovoy <maxg@mellanox.com> Fixes: fe631457ff3e ("blk-mq: map all HWQ also in hyperthreaded system") # v4.13. Reviewed-by: Chaitanya Kulkarni <chiatanya.kulkarni@wdc.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-01block: add SPDX tags to block layer files missing licensing informationChristoph Hellwig1-0/+1
Various block layer files do not have any licensing information at all. Add SPDX tags for the default kernel GPLv2 license to those. Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: initial support for multiple queue mapsJens Axboe1-4/+5
Add a queue offset to the tag map. This enables users to map iteratively, for each queue map type they support. Bump maximum number of supported maps to 2, we're now fully able to support more than 1 map. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Keith Busch <keith.busch@intel.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-11-07blk-mq: abstract out queue mapJens Axboe1-5/+5
This is in preparation for allowing multiple sets of maps per queue, if so desired. Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-04-10blk-mq: don't keep offline CPUs mapped to hctx 0Ming Lei1-5/+0
From commit 4b855ad37194 ("blk-mq: Create hctx for each present CPU), blk-mq doesn't remap queue after CPU topo is changed, that said when some of these offline CPUs become online, they are still mapped to hctx 0, then hctx 0 may become the bottleneck of IO dispatch and completion. This patch sets up the mapping from the beginning, and aligns to queue mapping for PCI device (blk_mq_pci_map_queues()). Cc: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: Keith Busch <keith.busch@intel.com> Cc: stable@vger.kernel.org Fixes: 4b855ad37194 ("blk-mq: Create hctx for each present CPU) Tested-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-07-24blk-mq: map queues to all present CPUsChristoph Hellwig1-2/+2
We already do this for PCI mappings, and the higher level code now expects that CPU on/offlining doesn't have an affect on the queue mappings. Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Max Gurtovoy <maxg@mellanox.com> Reviewed-by: Max Gurtovoy <maxg@mellanox.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-07-04Merge branch 'irq-core-for-linus' of ↵Linus Torvalds1-6/+4
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq updates from Thomas Gleixner: "The irq department delivers: - Expand the generic infrastructure handling the irq migration on CPU hotplug and convert X86 over to it. (Thomas Gleixner) Aside of consolidating code this is a preparatory change for: - Finalizing the affinity management for multi-queue devices. The main change here is to shut down interrupts which are affine to a outgoing CPU and reenabling them when the CPU comes online again. That avoids moving interrupts pointlessly around and breaking and reestablishing affinities for no value. (Christoph Hellwig) Note: This contains also the BLOCK-MQ and NVME changes which depend on the rework of the irq core infrastructure. Jens acked them and agreed that they should go with the irq changes. - Consolidation of irq domain code (Marc Zyngier) - State tracking consolidation in the core code (Jeffy Chen) - Add debug infrastructure for hierarchical irq domains (Thomas Gleixner) - Infrastructure enhancement for managing generic interrupt chips via devmem (Bartosz Golaszewski) - Constification work all over the place (Tobias Klauser) - Two new interrupt controller drivers for MVEBU (Thomas Petazzoni) - The usual set of fixes, updates and enhancements all over the place" * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (112 commits) irqchip/or1k-pic: Fix interrupt acknowledgement irqchip/irq-mvebu-gicp: Allocate enough memory for spi_bitmap irqchip/gic-v3: Fix out-of-bound access in gic_set_affinity nvme: Allocate queues for all possible CPUs blk-mq: Create hctx for each present CPU blk-mq: Include all present CPUs in the default queue mapping genirq: Avoid unnecessary low level irq function calls genirq: Set irq masked state when initializing irq_desc genirq/timings: Add infrastructure for estimating the next interrupt arrival time genirq/timings: Add infrastructure to track the interrupt timings genirq/debugfs: Remove pointless NULL pointer check irqchip/gic-v3-its: Don't assume GICv3 hardware supports 16bit INTID irqchip/gic-v3-its: Add ACPI NUMA node mapping irqchip/gic-v3-its-platform-msi: Make of_device_ids const irqchip/gic-v3-its: Make of_device_ids const irqchip/irq-mvebu-icu: Add new driver for Marvell ICU irqchip/irq-mvebu-gicp: Add new driver for Marvell GICP dt-bindings/interrupt-controller: Add DT binding for the Marvell ICU genirq/irqdomain: Remove auto-recursive hierarchy support irqchip/MSI: Use irq_domain_update_bus_token instead of an open coded access ...
2017-06-29blk-mq: map all HWQ also in hyperthreaded systemMax Gurtovoy1-46/+22
This patch performs sequential mapping between CPUs and queues. In case the system has more CPUs than HWQs then there are still CPUs to map to HWQs. In hyperthreaded system, map the unmapped CPUs and their siblings to the same HWQ. This actually fixes a bug that found unmapped HWQs in a system with 2 sockets, 18 cores per socket, 2 threads per core (total 72 CPUs) running NVMEoF (opens upto maximum of 64 HWQs). Performance results running fio (72 jobs, 128 iodepth) using null_blk (w/w.o patch): bs IOPS(read submit_queues=72) IOPS(write submit_queues=72) IOPS(read submit_queues=24) IOPS(write submit_queues=24) ----- ---------------------------- ------------------------------ ---------------------------- ----------------------------- 512 4890.4K/4723.5K 4524.7K/4324.2K 4280.2K/4264.3K 3902.4K/3909.5K 1k 4910.1K/4715.2K 4535.8K/4309.6K 4296.7K/4269.1K 3906.8K/3914.9K 2k 4906.3K/4739.7K 4526.7K/4330.6K 4301.1K/4262.4K 3890.8K/3900.1K 4k 4918.6K/4730.7K 4556.1K/4343.6K 4297.6K/4264.5K 3886.9K/3893.9K 8k 4906.4K/4748.9K 4550.9K/4346.7K 4283.2K/4268.8K 3863.4K/3858.2K 16k 4903.8K/4782.6K 4501.5K/4233.9K 4292.3K/4282.3K 3773.1K/3773.5K 32k 4885.8K/4782.4K 4365.9K/4184.2K 4307.5K/4289.4K 3780.3K/3687.3K 64k 4822.5K/4762.7K 2752.8K/2675.1K 4308.8K/4312.3K 2651.5K/2655.7K 128k 2388.5K/2313.8K 1391.9K/1375.7K 2142.8K/2152.2K 1395.5K/1374.2K Signed-off-by: Max Gurtovoy <maxg@mellanox.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-29blk-mq: Include all present CPUs in the default queue mappingChristoph Hellwig1-3/+2
This way we get a nice distribution independent of the current cpu online / offline state. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Jens Axboe <axboe@kernel.dk> Cc: Keith Busch <keith.busch@intel.com> Cc: linux-block@vger.kernel.org Cc: linux-nvme@lists.infradead.org Link: http://lkml.kernel.org/r/20170626102058.10200-2-hch@lst.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-11-09blk-mq: export blk_mq_map_queuesChristoph Hellwig1-0/+1
This will allow SCSI to have a single blk_mq_ops structure that either lets the LLDD map the queues to PCIe MSIx vectors or use the default. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Reviewed-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-09-15blk-mq: allow the driver to pass in a queue mappingChristoph Hellwig1-20/+5
This allows drivers specify their own queue mapping by overriding the setup-time function that builds the mq_map. This can be used for example to build the map based on the MSI-X vector mapping provided by the core interrupt layer for PCI devices. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-12-03blk-mq: Avoid memoryless numa node encoded in hctx numa_nodeRaghavendra K T1-1/+1
In architecture like powerpc, we can have cpus without any local memory attached to it (a.k.a memoryless nodes). In such cases cpu to node mapping can result in memory allocation hints for block hctx->numa_node populated with node values which does not have real memory. Instead use local_memory_node(), which is guaranteed to have memory. local_memory_node is a noop in other architectures that does not support memoryless nodes. Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-09-29blk-mq: avoid inserting requests before establishing new mappingAkinobu Mita1-4/+5
Notifier callbacks for CPU_ONLINE action can be run on the other CPU than the CPU which was just onlined. So it is possible for the process running on the just onlined CPU to insert request and run hw queue before establishing new mapping which is done by blk_mq_queue_reinit_notify(). This can cause a problem when the CPU has just been onlined first time since the request queue was initialized. At this time ctx->index_hw for the CPU, which is the index in hctx->ctxs[] for this ctx, is still zero before blk_mq_queue_reinit_notify() is called by notifier callbacks for CPU_ONLINE action. For example, there is a single hw queue (hctx) and two CPU queues (ctx0 for CPU0, and ctx1 for CPU1). Now CPU1 is just onlined and a request is inserted into ctx1->rq_list and set bit0 in pending bitmap as ctx1->index_hw is still zero. And then while running hw queue, flush_busy_ctxs() finds bit0 is set in pending bitmap and tries to retrieve requests in hctx->ctxs[0]->rq_list. But htx->ctxs[0] is a pointer to ctx0, so the request in ctx1->rq_list is ignored. Fix it by ensuring that new mapping is established before onlined cpu starts running. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Reviewed-by: Ming Lei <tom.leiming@gmail.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Ming Lei <tom.leiming@gmail.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@fb.com>
2015-05-27sched/topology: Rename topology_thread_cpumask() to topology_sibling_cpumask()Bartosz Golaszewski1-1/+1
Rename topology_thread_cpumask() to topology_sibling_cpumask() for more consistency with scheduler code. Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Benoit Cousson <bcousson@baylibre.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jean Delvare <jdelvare@suse.de> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Drokin <oleg.drokin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Russell King <linux@arm.linux.org.uk> Cc: Viresh Kumar <viresh.kumar@linaro.org> Link: http://lkml.kernel.org/r/1432645896-12588-2-git-send-email-bgolaszewski@baylibre.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-12-09blk-mq: Use all available hardware queuesBart Van Assche1-1/+1
Suppose that a system has two CPU sockets, three cores per socket, that it does not support hyperthreading and that four hardware queues are provided by a block driver. With the current algorithm this will lead to the following assignment of CPU cores to hardware queues: HWQ 0: 0 1 HWQ 1: 2 3 HWQ 2: 4 5 HWQ 3: (none) This patch changes the queue assignment into: HWQ 0: 0 1 HWQ 1: 2 HWQ 2: 3 4 HWQ 3: 5 In other words, this patch has the following three effects: - All four hardware queues are used instead of only three. - CPU cores are spread more evenly over hardware queues. For the above example the range of the number of CPU cores associated with a single HWQ is reduced from [0..2] to [1..2]. - If the number of HWQ's is a multiple of the number of CPU sockets it is now guaranteed that all CPU cores associated with a single HWQ reside on the same CPU socket. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Cc: Jens Axboe <axboe@fb.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Ming Lei <ming.lei@canonical.com> Cc: Alexander Gordeev <agordeev@redhat.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2014-11-25blk-mq: use 'nr_cpu_ids' as highest CPU ID count for hwq <-> cpu mapJens Axboe1-1/+1
We currently use num_possible_cpus(), but that breaks on sparc64 where the CPU ID space is discontig. Use nr_cpu_ids as the highest CPU ID instead, so we don't end up reading from invalid memory. Cc: stable@kernel.org # 3.13+ Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-28blk-mq: add file comments and update copyright noticesJens Axboe1-0/+5
None of the blk-mq files have an explanatory comment at the top for what that particular file does. Add that and add appropriate copyright notices as well. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-05-27blk-mq: pass in suggested NUMA node to ->alloc_hctx()Jens Axboe1-0/+16
Drivers currently have to figure this out on their own, and they are missing information to do it properly. The ones that did attempt to do it, do it wrong. So just pass in the suggested node directly to the alloc function. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-04-16blk-mq: split out tag initialization, support shared tagsChristoph Hellwig1-3/+3
Add a new blk_mq_tag_set structure that gets set up before we initialize the queue. A single blk_mq_tag_set structure can be shared by multiple queues. Signed-off-by: Christoph Hellwig <hch@lst.de> Modular export of blk_mq_{alloc,free}_tagset added by me. Signed-off-by: Jens Axboe <axboe@fb.com>
2014-03-20blk-mq: don't dump CPU -> hw queue map on driver loadJens Axboe1-10/+0
Now that we are out of initial debug/bringup mode, remove the verbose dump of the mapping table. Provide the mapping table in sysfs, under the hardware queue directory, in the cpu_list file. Signed-off-by: Jens Axboe <axboe@fb.com>
2013-10-25blk-mq: new multi-queue block IO queueing mechanismJens Axboe1-0/+108
Linux currently has two models for block devices: - The classic request_fn based approach, where drivers use struct request units for IO. The block layer provides various helper functionalities to let drivers share code, things like tag management, timeout handling, queueing, etc. - The "stacked" approach, where a driver squeezes in between the block layer and IO submitter. Since this bypasses the IO stack, driver generally have to manage everything themselves. With drivers being written for new high IOPS devices, the classic request_fn based driver doesn't work well enough. The design dates back to when both SMP and high IOPS was rare. It has problems with scaling to bigger machines, and runs into scaling issues even on smaller machines when you have IOPS in the hundreds of thousands per device. The stacked approach is then most often selected as the model for the driver. But this means that everybody has to re-invent everything, and along with that we get all the problems again that the shared approach solved. This commit introduces blk-mq, block multi queue support. The design is centered around per-cpu queues for queueing IO, which then funnel down into x number of hardware submission queues. We might have a 1:1 mapping between the two, or it might be an N:M mapping. That all depends on what the hardware supports. blk-mq provides various helper functions, which include: - Scalable support for request tagging. Most devices need to be able to uniquely identify a request both in the driver and to the hardware. The tagging uses per-cpu caches for freed tags, to enable cache hot reuse. - Timeout handling without tracking request on a per-device basis. Basically the driver should be able to get a notification, if a request happens to fail. - Optional support for non 1:1 mappings between issue and submission queues. blk-mq can redirect IO completions to the desired location. - Support for per-request payloads. Drivers almost always need to associate a request structure with some driver private command structure. Drivers can tell blk-mq this at init time, and then any request handed to the driver will have the required size of memory associated with it. - Support for merging of IO, and plugging. The stacked model gets neither of these. Even for high IOPS devices, merging sequential IO reduces per-command overhead and thus increases bandwidth. For now, this is provided as a potential 3rd queueing model, with the hope being that, as it matures, it can replace both the classic and stacked model. That would get us back to having just 1 real model for block devices, leaving the stacked approach to dm/md devices (as it was originally intended). Contributions in this patch from the following people: Shaohua Li <shli@fusionio.com> Alexander Gordeev <agordeev@redhat.com> Christoph Hellwig <hch@infradead.org> Mike Christie <michaelc@cs.wisc.edu> Matias Bjorling <m@bjorling.me> Jeff Moyer <jmoyer@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>