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2023-01-29drbd: make limits unsignedChristoph Böhmwalder
These are almost always used as unsigned integers, so mark them as such. Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-4-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29drbd: fix DRBD_VOLUME_MAX 65535 -> 65534Robert Altnoeder
The protocol uses -1 as a reserved value for 'no specific volume', and since the protocol field is a 16 bit unsigned value, -1 is converted to 65535. Therefore, limit the range of valid volume numbers to [0, 65534]. Signed-off-by: Robert Altnoeder <robert.altnoeder@linbit.com> Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-3-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29drbd: adjust drbd_limits license headerChristoph Böhmwalder
See also commit 93c68cc46a07 ("drbd: use consistent license"). We only want to license drbd under GPL-2.0, so use the corresponding SPDX header consistently. Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-2-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29drbd: split off drbd_config into separate fileChristoph Böhmwalder
To be more similar to what we do in the out-of-tree module and ease the upstreaming process. Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123506.144082-4-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29drbd: drop API_VERSION defineChristoph Böhmwalder
Use the genetlink api version as defined in drbd_genl_api.h. Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123506.144082-3-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29drbd: split off drbd_buildtag into separate fileChristoph Böhmwalder
To be more similar to what we do in the out-of-tree module and ease the upstreaming process. Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123506.144082-2-christoph.boehmwalder@linbit.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block: add a BUILD_BUG_ON() for adding more bio flags than we have spaceJens Axboe
We have BIO_FLAG_LAST in the enum for bio specific flags, but it's not used to check that we're not exceeding the size of them. Add such a check. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block: save user max_sectors limitKeith Busch
The user can set the max_sectors limit to any valid value via sysfs /sys/block/<dev>/queue/max_sectors_kb attribute. If the device limits are ever rescanned, though, the limit reverts back to the potentially artificially low BLK_DEF_MAX_SECTORS value. Preserve the user's setting as the max_sectors limit as long as it's valid. The user can reset back to defaults by writing 0 to the sysfs file. Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20230105205146.3610282-3-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block: make BLK_DEF_MAX_SECTORS unsignedKeith Busch
This is used as an unsigned value, so define it that way to avoid having to cast it. Suggested-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Keith Busch <kbusch@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20230105205146.3610282-2-kbusch@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: balance I/O injection among underutilized actuatorsDavide Zini
Upon the invocation of its dispatch function, BFQ returns the next I/O request of the in-service bfq_queue, unless some exception holds. One such exception is that there is some underutilized actuator, different from the actuator for which the in-service queue contains I/O, and that some other bfq_queue happens to contain I/O for such an actuator. In this case, the next I/O request of the latter bfq_queue, and not of the in-service bfq_queue, is returned (I/O is injected from that bfq_queue). To find such an actuator, a linear scan, in increasing index order, is performed among actuators. Performing a linear scan entails a prioritization among actuators: an underutilized actuator may be considered for injection only if all actuators with a lower index are currently fully utilized, or if there is no pending I/O for any lower-index actuator that happens to be underutilized. This commits breaks this prioritization and tends to distribute injection uniformly across actuators. This is obtained by adding the following condition to the linear scan: even if an actuator A is underutilized, A is however skipped if its load is higher than that of the next actuator. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Davide Zini <davidezini2@gmail.com> Link: https://lore.kernel.org/r/20230103145503.71712-9-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: inject I/O to underutilized actuatorsDavide Zini
The main service scheme of BFQ for sync I/O is serving one sync bfq_queue at a time, for a while. In particular, BFQ enforces this scheme when it deems the latter necessary to boost throughput or to preserve service guarantees. Unfortunately, when BFQ enforces this policy, only one actuator at a time gets served for a while, because each bfq_queue contains I/O only for one actuator. The other actuators may remain underutilized. Actually, BFQ may serve (inject) extra I/O, taken from other bfq_queues, in parallel with that of the in-service queue. This injection mechanism may provide the ground for dealing also with the above actuator-underutilization problem. Yet BFQ does not take the actuator load into account when choosing which queue to pick extra I/O from. In addition, BFQ may happen to inject extra I/O only when the in-service queue is temporarily empty. In view of these facts, this commit extends the injection mechanism in such a way that the latter: (1) takes into account also the actuator load; (2) checks such a load on each dispatch, and injects I/O for an underutilized actuator, if there is one and there is I/O for it. To perform the check in (2), this commit introduces a load threshold, currently set to 4. A linear scan of each actuator is performed, until an actuator is found for which the following two conditions hold: the load of the actuator is below the threshold, and there is at least one non-in-service queue that contains I/O for that actuator. If such a pair (actuator, queue) is found, then the head request of that queue is returned for dispatch, instead of the head request of the in-service queue. We have set the threshold, empirically, to the minimum possible value for which an actuator is fully utilized, or close to be fully utilized. By doing so, injected I/O 'steals' as few drive-queue slots as possibile to the in-service queue. This reduces as much as possible the probability that the service of I/O from the in-service bfq_queue gets delayed because of slot exhaustion, i.e., because all the slots of the drive queue are filled with I/O injected from other queues (NCQ provides for 32 slots). This new mechanism also counters actuator underutilization in the case of asymmetric configurations of bfq_queues. Namely if there are few bfq_queues containing I/O for some actuators and many bfq_queues containing I/O for other actuators. Or if the bfq_queues containing I/O for some actuators have lower weights than the other bfq_queues. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Davide Zini <davidezini2@gmail.com> Link: https://lore.kernel.org/r/20230103145503.71712-8-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: retrieve independent access ranges from request queueFederico Gavioli
This patch implements the code to gather the content of the independent_access_ranges structure from the request_queue and copy it into the queue's bfq_data. This copy is done at queue initialization. We copy the access ranges into the bfq_data to avoid taking the queue lock each time we access the ranges. This implementation, however, puts a limit to the maximum independent ranges supported by the scheduler. Such a limit is equal to the constant BFQ_MAX_ACTUATORS. This limit was placed to avoid the allocation of dynamic memory. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Co-developed-by: Rory Chen <rory.c.chen@seagate.com> Signed-off-by: Rory Chen <rory.c.chen@seagate.com> Signed-off-by: Federico Gavioli <f.gavioli97@gmail.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20230103145503.71712-7-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: split also async bfq_queues on a per-actuator basisDavide Zini
Similarly to sync bfq_queues, also async bfq_queues need to be split on a per-actuator basis. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Signed-off-by: Davide Zini <davidezini2@gmail.com> Link: https://lore.kernel.org/r/20230103145503.71712-6-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: turn bfqq_data into an array in bfq_io_cqPaolo Valente
When a bfq_queue Q is merged with another queue, several pieces of information are saved about Q. These pieces are stored in the bfqq_data field in the bfq_io_cq data structure of the process associated with Q. Yet, with a multi-actuator drive, a process may get associated with multiple bfq_queues: one queue for each of the N actuators. Each of these queues may undergo a merge. So, the bfq_io_cq data structure must be able to accommodate the above information for N queues. This commit solves this problem by turning the bfqq_data scalar field into an array of N elements (and by changing code so as to handle this array). This solution is written under the assumption that bfq_queues associated with different actuators cannot be cross-merged. This assumption holds naturally with basic queue merging: the latter is triggered by spatial locality, and sectors for different actuators are not close to each other (apart from the corner case of the last sectors served by a given actuator and the first sectors served by the next actuator). As for stable cross-merging, the assumption here is that it is disabled. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Gabriele Felici <felicigb@gmail.com> Signed-off-by: Gianmarco Lusvardi <glusvardi@posteo.net> Signed-off-by: Giulio Barabino <giuliobarabino99@gmail.com> Signed-off-by: Emiliano Maccaferri <inbox@emilianomaccaferri.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20230103145503.71712-5-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: move io_cq-persistent bfqq data into a dedicated structPaolo Valente
With a multi-actuator drive, a process may get associated with multiple bfq_queues: one queue for each of the N actuators. So, the bfq_io_cq data structure must be able to accommodate its per-queue persistent information for N queues. Currently it stores this information for just one queue, in several scalar fields. This is a preparatory commit for moving to accommodating persistent information for N queues. In particular, this commit packs all the above scalar fields into a single data structure. Then there is now only one field, in bfq_io_cq, that stores all the above information. This scalar field will then be turned into an array by a following commit. Suggested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Gianmarco Lusvardi <glusvardi@posteo.net> Signed-off-by: Giulio Barabino <giuliobarabino99@gmail.com> Signed-off-by: Emiliano Maccaferri <inbox@emilianomaccaferri.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20230103145503.71712-4-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: forbid stable merging of queues associated with different actuatorsPaolo Valente
If queues associated with different actuators are merged, then control is lost on each actuator. Therefore some actuator may be underutilized, and throughput may decrease. This problem cannot occur with basic queue merging, because the latter is triggered by spatial locality, and sectors for different actuators are not close to each other. Yet it may happen with stable merging. To address this issue, this commit prevents stable merging from occurring among queues associated with different actuators. Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20230103145503.71712-3-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29block, bfq: split sync bfq_queues on a per-actuator basisPaolo Valente
Single-LUN multi-actuator SCSI drives, as well as all multi-actuator SATA drives appear as a single device to the I/O subsystem [1]. Yet they address commands to different actuators internally, as a function of Logical Block Addressing (LBAs). A given sector is reachable by only one of the actuators. For example, Seagate’s Serial Advanced Technology Attachment (SATA) version contains two actuators and maps the lower half of the SATA LBA space to the lower actuator and the upper half to the upper actuator. Evidently, to fully utilize actuators, no actuator must be left idle or underutilized while there is pending I/O for it. The block layer must somehow control the load of each actuator individually. This commit lays the ground for allowing BFQ to provide such a per-actuator control. BFQ associates an I/O-request sync bfq_queue with each process doing synchronous I/O, or with a group of processes, in case of queue merging. Then BFQ serves one bfq_queue at a time. While in service, a bfq_queue is emptied in request-position order. Yet the same process, or group of processes, may generate I/O for different actuators. In this case, different streams of I/O (each for a different actuator) get all inserted into the same sync bfq_queue. So there is basically no individual control on when each stream is served, i.e., on when the I/O requests of the stream are picked from the bfq_queue and dispatched to the drive. This commit enables BFQ to control the service of each actuator individually for synchronous I/O, by simply splitting each sync bfq_queue into N queues, one for each actuator. In other words, a sync bfq_queue is now associated to a pair (process, actuator). As a consequence of this split, the per-queue proportional-share policy implemented by BFQ will guarantee that the sync I/O generated for each actuator, by each process, receives its fair share of service. This is just a preparatory patch. If the I/O of the same process happens to be sent to different queues, then each of these queues may undergo queue merging. To handle this event, the bfq_io_cq data structure must be properly extended. In addition, stable merging must be disabled to avoid loss of control on individual actuators. Finally, also async queues must be split. These issues are described in detail and addressed in next commits. As for this commit, although multiple per-process bfq_queues are provided, the I/O of each process or group of processes is still sent to only one queue, regardless of the actuator the I/O is for. The forwarding to distinct bfq_queues will be enabled after addressing the above issues. [1] https://www.linaro.org/blog/budget-fair-queueing-bfq-linux-io-scheduler-optimizations-for-multi-actuator-sata-hard-drives/ Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Gabriele Felici <felicigb@gmail.com> Signed-off-by: Carmine Zaccagnino <carmine@carminezacc.com> Signed-off-by: Paolo Valente <paolo.valente@linaro.org> Link: https://lore.kernel.org/r/20230103145503.71712-2-paolo.valente@linaro.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: always go async for unsupported open flagsDylan Yudaken
No point in issuing -> return -EAGAIN -> go async, when it can be done upfront. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127135227.3646353-5-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: always go async for unsupported fadvise flagsDylan Yudaken
No point in issuing -> return -EAGAIN -> go async, when it can be done upfront. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127135227.3646353-4-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: for requests that require async, force itDylan Yudaken
Some requests require being run async as they do not support non-blocking. Instead of trying to issue these requests, getting -EAGAIN and then queueing them for async issue, rather just force async upfront. Add WARN_ON_ONCE to make sure surprising code paths do not come up, however in those cases the bug would end up being a blocking io_uring_enter(2) which should not be critical. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127135227.3646353-3-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: if a linked request has REQ_F_FORCE_ASYNC then run it asyncDylan Yudaken
REQ_F_FORCE_ASYNC was being ignored for re-queueing linked requests. Instead obey that flag. Signed-off-by: Dylan Yudaken <dylany@meta.com> Link: https://lore.kernel.org/r/20230127135227.3646353-2-dylany@meta.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: add reschedule point to handle_tw_list()Jens Axboe
If CONFIG_PREEMPT_NONE is set and the task_work chains are long, we could be running into issues blocking others for too long. Add a reschedule check in handle_tw_list(), and flush the ctx if we need to reschedule. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: add a conditional reschedule to the IOPOLL cancelation loopJens Axboe
If the kernel is configured with CONFIG_PREEMPT_NONE, we could be sitting in a tight loop reaping events but not giving them a chance to finish. This results in a trace ala: rcu: INFO: rcu_sched self-detected stall on CPU rcu: 2-...!: (5249 ticks this GP) idle=935c/1/0x4000000000000000 softirq=4265/4274 fqs=1 (t=5251 jiffies g=465 q=4135 ncpus=4) rcu: rcu_sched kthread starved for 5249 jiffies! g465 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_sched state:R running task stack:0 pid:12 ppid:2 flags:0x00000008 Call trace: __switch_to+0xb0/0xc8 __schedule+0x43c/0x520 schedule+0x4c/0x98 schedule_timeout+0xbc/0xdc rcu_gp_fqs_loop+0x308/0x344 rcu_gp_kthread+0xd8/0xf0 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 rcu: Stack dump where RCU GP kthread last ran: Task dump for CPU 0: task:kworker/u8:10 state:R running task stack:0 pid:89 ppid:2 flags:0x0000000a Workqueue: events_unbound io_ring_exit_work Call trace: __switch_to+0xb0/0xc8 0xffff0000c8fefd28 CPU: 2 PID: 95 Comm: kworker/u8:13 Not tainted 6.2.0-rc5-00042-g40316e337c80-dirty #2759 Hardware name: linux,dummy-virt (DT) Workqueue: events_unbound io_ring_exit_work pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : io_do_iopoll+0x344/0x360 lr : io_do_iopoll+0xb8/0x360 sp : ffff800009bebc60 x29: ffff800009bebc60 x28: 0000000000000000 x27: 0000000000000000 x26: ffff0000c0f67d48 x25: ffff0000c0f67840 x24: ffff800008950024 x23: 0000000000000001 x22: 0000000000000000 x21: ffff0000c27d3200 x20: ffff0000c0f67840 x19: ffff0000c0f67800 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000001 x13: 0000000000000001 x12: 0000000000000000 x11: 0000000000000179 x10: 0000000000000870 x9 : ffff800009bebd60 x8 : ffff0000c27d3ad0 x7 : fefefefefefefeff x6 : 0000646e756f626e x5 : ffff0000c0f67840 x4 : 0000000000000000 x3 : ffff0000c2398000 x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: io_do_iopoll+0x344/0x360 io_uring_try_cancel_requests+0x21c/0x334 io_ring_exit_work+0x90/0x40c process_one_work+0x1a4/0x254 worker_thread+0x1ec/0x258 kthread+0xb8/0xc8 ret_from_fork+0x10/0x20 Add a cond_resched() in the cancelation IOPOLL loop to fix this. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: return normal tw run linking optimisationPavel Begunkov
io_submit_flush_completions() may produce new task_work items, so it's a good idea to recheck the task_work list after flushing completions. The optimisation is not new and was accidentially removed by f88262e60bb9 ("io_uring: lockless task list") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a7ed5ede84de190832cc33ebbcdd6e91cd90f5b6.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: refactor tctx_task_workPavel Begunkov
Merge almost identical sections of tctx_task_work(), this will make code modifications later easier and also inlines handle_tw_list(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/d06592d91e3e7559e7a4dbb8907d110863008dc7.1674484266.git.asml.silence@gmail.com [axboe: fold in setting count to zero patch from Tom Rix] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: refactor io_put_task helpersPavel Begunkov
Add a helper for putting refs from the target task context, rename __io_put_task() and add a couple of comments around. Use the remote version for __io_req_complete_post(), the local is only needed for __io_submit_flush_completions(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/3bf92ebd594769d8a5d648472a8e335f2031d542.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: refactor req allocationPavel Begunkov
Follow the io_get_sqe pattern returning the result via a pointer and hide request cache refill inside io_alloc_req(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8c37c2e8a3cb5e4cd6a8ae3b91371227a92708a6.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: improve io_get_sqePavel Begunkov
Return an SQE from io_get_sqe() as a parameter and use the return value to determine if it failed or not. This enables the compiler to compile out the sqe NULL check when we know that the return SQE is valid. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/9cceb11329240ea097dffef6bf0a675bca14cf42.1674484266.git.asml.silence@gmail.com [axboe: remove bogus const modifier on return value] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: kill outdated comment about overflow flushPavel Begunkov
__io_cqring_overflow_flush() doesn't return anything anymore, remove outdate comment. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/4ce2bcbb17eac80cdf883fd1459d5ee6586e238c.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: use user visible tail in io_uring_poll()Pavel Begunkov
We return POLLIN from io_uring_poll() depending on whether there are CQEs for the userspace, and so we should use the user visible tail pointer instead of a transient cached value. Cc: stable@vger.kernel.org Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/228ffcbf30ba98856f66ffdb9a6a60ead1dd96c0.1674484266.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: pass in io_issue_def to io_assign_file()Jens Axboe
This generates better code for me, avoiding an extra load on arm64, and both call sites already have this variable available for easy passing. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: Enable KASAN for request cacheBreno Leitao
Every io_uring request is represented by struct io_kiocb, which is cached locally by io_uring (not SLAB/SLUB) in the list called submit_state.freelist. This patch simply enabled KASAN for this free list. This list is initially created by KMEM_CACHE, but later, managed by io_uring. This patch basically poisons the objects that are not used (i.e., they are the free list), and unpoisons it when the object is allocated/removed from the list. Touching these poisoned objects while in the freelist will cause a KASAN warning. Suggested-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: handle TIF_NOTIFY_RESUME when checking for task_workJens Axboe
If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work() for PF_IO_WORKER threads. They never return to usermode, hence never get a chance to process any items that are marked by this flag. Most notably this includes the final put of files, but also any throttling markers set by block cgroups. Cc: stable@vger.kernel.org # 5.10+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring/msg-ring: ensure flags passing works for task_work completionsJens Axboe
If the target ring is using IORING_SETUP_SINGLE_ISSUER and we're posting a message from a different thread, then we need to ensure that the fallback task_work that posts the CQE knwos about the flags passing as well. If not we'll always be posting 0 as the flags. Fixes: 3563d7ed58a5 ("io_uring/msg_ring: Pass custom flags to the cqe") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: Split io_issue_def structBreno Leitao
This patch removes some "cold" fields from `struct io_issue_def`. The plan is to keep only highly used fields into `struct io_issue_def`, so, it may be hot in the cache. The hot fields are basically all the bitfields and the callback functions for .issue and .prep. The other less frequently used fields are now located in a secondary and cold struct, called `io_cold_def`. This is the size for the structs: Before: io_issue_def = 56 bytes After: io_issue_def = 24 bytes; io_cold_def = 40 bytes Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20230112144411.2624698-2-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: Rename struct io_op_defBreno Leitao
The current io_op_def struct is becoming huge and the name is a bit generic. The goal of this patch is to rename this struct to `io_issue_def`. This struct will contain the hot functions associated with the issue code path. For now, this patch only renames the structure, and an upcoming patch will break up the structure in two, moving the non-issue fields to a secondary struct. Signed-off-by: Breno Leitao <leitao@debian.org> Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/20230112144411.2624698-1-leitao@debian.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: refactor __io_req_complete_postPavel Begunkov
Keep parts of __io_req_complete_post() relying on req->flags together so the value can be cached. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/2b4fbb42f404a0e75c4d9f0a5b16f314a839d0a9.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: optimise ctx flags layoutPavel Begunkov
There may be different cost for reeading just one byte or more, so it's benificial to keep ctx flag bits that we access together in a single byte. That affected code generation of __io_cq_unlock_post_flush() and removed one memory load. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/bbe8ca4705704690319d65e45845f9fc9d35f420.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: simplify fallback executionPavel Begunkov
Lock the ring with uring_lock in io_fallback_req_func(), which should make it a bit safer and easier. With that we also don't need refs pinning as io_ring_exit_work() will wait until uring_lock is freed. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/56170e6a0cbfc8edee2794c6613e8f6f1d76d276.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: don't export io_put_task()Pavel Begunkov
io_put_task() is only used in uring.c so enclose it there together with __io_put_task(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/43c7f9227e2ab215f1a6069dadbc5382bed346fe.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: return back links tw run optimisationPavel Begunkov
io_submit_flush_completions() may queue new requests for tw execution, especially true for linked requests. Recheck the tw list for emptiness after flushing completions. Note that this doesn't really fix the commit referenced below, but it does reinstate an optimization that existed before that got merged. Fixes: f88262e60bb9 ("io_uring: lockless task list") Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/6328acdbb5e60efc762b18003382de077e6e1367.1673887636.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: make io_sqpoll_wait_sq return voidQuanfa Fu
Change the return type to void since it always return 0, and no need to do the checking in syscall io_uring_enter. Signed-off-by: Quanfa Fu <quanfafu@gmail.com> Link: https://lore.kernel.org/r/20230115071519.554282-1-quanfafu@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: optimise deferred tw executionPavel Begunkov
We needed fake nodes in __io_run_local_work() and to avoid unecessary wake ups while the task already running task_works, but we don't need them anymore since wake ups are protected by cq_waiting, which is always cleared by the time we're executing deferred task_work items. Note that because of loose sync around cq_waiting clearing io_req_local_work_add() may wake the task more than once, but that's fine and should be rare to not hurt perf. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/8839534891f0a2f1076e78554a31ea7e099f7de5.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: add io_req_local_work_add wake fast pathPavel Begunkov
Don't wake the master task after queueing a deferred tw unless it's currently waiting in io_cqring_wait. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/717702d772825a6647e6c315b4690277ba84c3fc.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: waitqueue-less cq waitingPavel Begunkov
With DEFER_TASKRUN only ctx->submitter_task might be waiting for CQEs, we can use this to optimise io_cqring_wait(). Replace ->cq_wait waitqueue with waking the task directly. It works but misses an important optimisation covered by the following patch, so this patch without follow ups might hurt performance. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/103d174d35d919d4cb0922d8a9c93a8f0c35f74a.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: wake up optimisationsPavel Begunkov
Flush completions is done either from the submit syscall or by the task_work, both are in the context of the submitter task, and when it goes for a single threaded rings like implied by ->task_complete, there won't be any waiters on ->cq_wait but the master task. That means that there can be no tasks sleeping on cq_wait while we run __io_submit_flush_completions() and so waking up can be skipped. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/60ad9768ec74435a0ddaa6eec0ffa7729474f69f.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: add lazy poll_wq activationPavel Begunkov
Even though io_poll_wq_wake()'s waitqueue_active reuses a barrier we do for another waitqueue, it's not going to be the case in the future and so we want to have a fast path for it when the ring has never been polled. Move poll_wq wake ups into __io_commit_cqring_flush() using a new flag called ->poll_activated. The idea behind the flag is to set it when the ring was polled for the first time. This requires additional sync to not miss events, which is done here by using task_work for ->task_complete rings, and by default enabling the flag for all other types of rings. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/060785e8e9137a920b232c0c7f575b131af19cac.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: separate wq for ring pollingPavel Begunkov
Don't use ->cq_wait for ring polling but add a separate wait queue for it. We need it for following patches. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/dea0be0bf990503443c5c6c337fc66824af7d590.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: move io_run_local_work_lockedPavel Begunkov
io_run_local_work_locked() is only used in io_uring.c, move it there. With that we can also make __io_run_local_work() static. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/91757bcb33e5774e49fed6f2b6e058630608119b.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29io_uring: mark io_run_local_work staticPavel Begunkov
io_run_local_work is enclosed in io_uring.c, we don't need to export it. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/b477fb81f5e77044f724a06fe245d5c078659364.1673274244.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>