- 29 Jan, 2023 40 commits
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Christoph Hellwig authored
s390 iterates over the bio using bio_for_each_segment and doesn't need any bio splitting. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> Link: https://lore.kernel.org/r/20230123075356.60847-1-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Hellwig authored
ps3vram iterates over the bio one segment, that is page aligned and max page sized chunk, a time. Because of that there is no point in calling bio_split_to_limits, or explicitly setting the default limits that are only used by bio_split_to_limits. Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Geoff Levand <geoff@infradead.org> Link: https://lore.kernel.org/r/20230123074718.57951-1-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Jens Axboe authored
We ran into an issue where a production workload would randomly grind to a halt and not continue until the pending IO had timed out. This turned out to be a complicated interaction between queue freezing and polled IO: 1) You have an application that does polled IO. At any point in time, there may be polled IO pending. 2) You have a monitoring application that issues a passthrough command, which is marked with side effects such that it needs to freeze the queue. 3) Passthrough command is started, which calls blk_freeze_queue_start() on the device. At this point the queue is marked frozen, and any attempt to enter the queue will fail (for non-blocking) or block. 4) Now the driver calls blk_mq_freeze_queue_wait(), which will return when the queue is quiesced and pending IO has completed. 5) The pending IO is polled IO, but any attempt to poll IO through the normal iocb_bio_iopoll() -> bio_poll() will fail when it gets to bio_queue_enter() as the queue is frozen. Rather than poll and complete IO, the polling threads will sit in a tight loop attempting to poll, but failing to enter the queue to do so. The end result is that progress for either application will be stalled until all pending polled IO has timed out. This causes obvious huge latency issues for the application doing polled IO, but also long delays for passthrough command. Fix this by treating queue enter for polled IO just like we do for timeouts. This allows quick quiesce of the queue as we still poll and complete this IO, while still disallowing queueing up new IO. Reviewed-by: Keith Busch <kbusch@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Li Nan authored
vrate_min is calculated by DIV64_U64_ROUND_UP, but vrate_max is calculated by div64_u64. Vrate_min may be 1 greater than vrate_max if the input values min and max of cost.qos are equal. Signed-off-by: Li Nan <linan122@huawei.com> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230117070806.3857142-6-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Li Nan authored
echo max of u64 to cost.model can cause divide by 0 error. # echo 8:0 rbps=18446744073709551615 > /sys/fs/cgroup/io.cost.model divide error: 0000 [#1] PREEMPT SMP RIP: 0010:calc_lcoefs+0x4c/0xc0 Call Trace: <TASK> ioc_refresh_params+0x2b3/0x4f0 ioc_cost_model_write+0x3cb/0x4c0 ? _copy_from_iter+0x6d/0x6c0 ? kernfs_fop_write_iter+0xfc/0x270 cgroup_file_write+0xa0/0x200 kernfs_fop_write_iter+0x17d/0x270 vfs_write+0x414/0x620 ksys_write+0x73/0x160 __x64_sys_write+0x1e/0x30 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd calc_lcoefs() uses the input value of cost.model in DIV_ROUND_UP_ULL, overflow would happen if bps plus IOC_PAGE_SIZE is greater than ULLONG_MAX, it can cause divide by 0 error. Fix the problem by setting basecost Signed-off-by: Li Nan <linan122@huawei.com> Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230117070806.3857142-5-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Yu Kuai authored
Otherwise, user might get abnormal values if params is updated concurrently. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230117070806.3857142-4-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Yu Kuai authored
iocost is based on rq_qos, which can only work for request based device, thus it doesn't make sense to configure iocost for bio based device. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230117070806.3857142-3-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Yu Kuai authored
This patch fixs that the return value of match_u64() from ioc_qos_write() is not checked, Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230117070806.3857142-2-yukuai1@huaweicloud.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Arnd Bergmann authored
The behavior of 'enum' types has changed in gcc-13, so now the UNBUSY_THR_PCT constant is interpreted as a 64-bit number because it is defined as part of the same enum definition as some other constants that do not fit within a 32-bit integer. This in turn leads to some inefficient code on 32-bit architectures as well as a link error: arm-linux-gnueabi/bin/arm-linux-gnueabi-ld: block/blk-iocost.o: in function `ioc_timer_fn': blk-iocost.c:(.text+0x68e8): undefined reference to `__aeabi_uldivmod' arm-linux-gnueabi-ld: blk-iocost.c:(.text+0x6908): undefined reference to `__aeabi_uldivmod' Split the enum definition to keep the 64-bit timing constants in a separate enum type from those constants that can clearly fit within a smaller type. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230118080706.3303186-1-arnd@kernel.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
Fix the following warning: Documentation/block/ublk.rst:157: WARNING: Enumerated list ends without a blank line; unexpected unindent. Documentation/block/ublk.rst:171: WARNING: Enumerated list ends without a blank line; unexpected unindent. Fixes: 56f5160bc1b8 ("ublk_drv: add mechanism for supporting unprivileged ublk device") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230118042318.127900-1-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Pankaj Raghav authored
Add a generic bdev_zone_no() helper to calculate zone number for a given sector in a block device. This helper internally uses disk_zone_no() to find the zone number. Use the helper bdev_zone_no() to calculate nr of zones. This lets us make modifications to the math if needed in one place. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Link: https://lore.kernel.org/r/20230110143635.77300-4-p.raghav@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Pankaj Raghav authored
Instead of open coding to check for zone start, add a helper to improve readability and store the logic in one place. Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20230110143635.77300-3-p.raghav@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Pankaj Raghav authored
Remove the superfluous request queue check in bdev_is_zoned() as bdev_get_queue() can never return NULL. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Pankaj Raghav <p.raghav@samsung.com> Link: https://lore.kernel.org/r/20230110143635.77300-2-p.raghav@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Anuj Gupta authored
This patch modifies the present check, so that bio-cache is not limited to iopoll. Signed-off-by: Anuj Gupta <anuj20.g@samsung.com> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> Link: https://lore.kernel.org/r/20230117120638.72254-3-anuj20.g@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Anuj Gupta authored
This patch sets REQ_ALLOC_CACHE flag for uring-passthru requests. This is a prep-patch so that normal / IRQ-driven uring-passthru I/Os can also leverage bio-cache. Signed-off-by: Anuj Gupta <anuj20.g@samsung.com> Signed-off-by: Kanchan Joshi <joshi.k@samsung.com> Link: https://lore.kernel.org/r/20230117120638.72254-2-anuj20.g@samsung.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
unprivileged ublk device is helpful for container use case, such as: ublk device created in one unprivileged container can be controlled and accessed by this container only. Implement this feature by adding flag of UBLK_F_UNPRIVILEGED_DEV, and if this flag isn't set, any control command has been run from privileged user. Otherwise, any control command can be sent from any unprivileged user, but the user has to be permitted to access the ublk char device to be controlled. In case of UBLK_F_UNPRIVILEGED_DEV: 1) for command UBLK_CMD_ADD_DEV, it is always allowed, and user needs to provide owner's uid/gid in this command, so that udev can set correct ownership for the created ublk device, since the device owner uid/gid can be queried via command of UBLK_CMD_GET_DEV_INFO. 2) for other control commands, they can only be run successfully if the current user is allowed to access the specified ublk char device, for running the permission check, path of the ublk char device has to be provided by these commands. Also add one control of command UBLK_CMD_GET_DEV_INFO2 which always include the char dev path in payload since userspace may not have knowledge if this device is created in unprivileged mode. For applying this mechanism, system administrator needs to take the following policies: 1) chmod 0666 /dev/ublk-control 2) change ownership of ublkcN & ublkbN - chown owner_uid:owner_gid /dev/ublkcN - chown owner_uid:owner_gid /dev/ublkbN Both can be done via one simple udev rule. Userspace: https://github.com/ming1/ubdsrv/tree/unprivileged-ublk 'ublk add -t $TYPE --un_privileged=1' is for creating one un-privileged ublk device if the user is un-privileged. Link: https://lore.kernel.org/linux-block/YoOr6jBfgVm8GvWg@stefanha-x1.localdomain/Suggested-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230106041711.914434-7-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
Prepare for supporting unprivileged ublk device by limiting max number ublk devices added. Otherwise too many ublk devices could be added by un-trusted user, which can be thought as one DoS. Reviewed-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230106041711.914434-6-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
Userspace side only knows device ID, but the associated path of ublkc* and ublkb* could be changed by udev, and that depends on userspace's policy, so add parameter of UBLK_PARAM_TYPE_DEVT for retrieving major/minor of the ublkc* and ublkb*, then user may figure out major/minor of the ublk disks he/she owns. With major/minor, it is easy to find the device node path. Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230106041711.914434-5-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
It is annoying for each control command handler to get/put ublk device and deal with failure. Control command handler is simplified a lot by moving ublk_get_device_from_id into ublk_ctrl_uring_cmd(). Reviewed-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230106041711.914434-4-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
If any ubq daemon is unprivileged, the ublk char device is allowed for unprivileged user actually, and we can't trust the current user, so not probe partitions. Fixes: 71f28f31 ("ublk_drv: add io_uring based userspace block driver") Reviewed-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230106041711.914434-3-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Ming Lei authored
No one uses 'nr_aborted_queues' any more, so remove it. Reviewed-by: ZiyangZhang <ZiyangZhang@linux.alibaba.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20230106041711.914434-2-ming.lei@redhat.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Jens Axboe authored
If we're doing a large IO request which needs to be split into multiple bios for issue, then we can run into the same situation as the below marked commit fixes - parts will complete just fine, one or more parts will fail to allocate a request. This will result in a partially completed read or write request, where the caller gets EAGAIN even though parts of the IO completed just fine. Do the same for large bios as we do for splits - fail a NOWAIT request with EAGAIN. This isn't technically fixing an issue in the below marked patch, but for stable purposes, we should have either none of them or both. This depends on: 613b1488 ("block: handle bio_split_to_limits() NULL return") Cc: stable@vger.kernel.org # 5.15+ Fixes: 9cea62b2 ("block: don't allow splitting of a REQ_NOWAIT bio") Link: https://github.com/axboe/liburing/issues/766Reported-and-tested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Andreas Gruenbacher authored
Signed-off-by: Andreas Gruenbacher <agruen@linbit.com> Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-9-christoph.boehmwalder@linbit.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Lars Ellenberg authored
Trying to remove an "empty" (just initialized, or "cleared") interval from the tree, this results in an endless loop. As we typically protect the tree with a spinlock_irq, the result is a hung system. Be nice to error cleanup code paths, ignore removal of empty intervals. Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com> Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-8-christoph.boehmwalder@linbit.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-7-christoph.boehmwalder@linbit.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
This require_context attribute originated in a proposed sparse patch by Philipp Reisner back in 2008. Johannes Berg had a different solution to a similar problem, and that patch "won" in the end; so the require_context thing never got merged. The whole history can be read at [0]. DRBD kept using these annotations anyway for a while. Nowadays, on a modern unmodified sparse, they obviously do nothing, and they are hardly used anymore anyway. So, just remove the definitions of these macros. [0] https://www.spinics.net/lists/linux-sparse/msg01150.htmlSigned-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-6-christoph.boehmwalder@linbit.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Reviewed-by: Joel Colledge <joel.colledge@linbit.com> Link: https://lore.kernel.org/r/20230113123538.144276-5-christoph.boehmwalder@linbit.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Robert Altnoeder authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
See also commit 93c68cc4 ("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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Böhmwalder authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Jens Axboe authored
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>
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Keith Busch authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Keith Busch authored
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.comSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Davide Zini authored
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.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Davide Zini authored
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.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Federico Gavioli authored
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.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>
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Davide Zini authored
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.orgSigned-off-by: Jens Axboe <axboe@kernel.dk>
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