- Sep 10, 2024
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Yu Kuai authored
last_low_overflow_time is not used anymore after commit bf20ab53 ("blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW"). Signed-off-by:
Yu Kuai <yukuai3@huawei.com> Acked-by:
Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20240903135149.271857-2-yukuai1@huaweicloud.com Signed-off-by:
Jens Axboe <axboe@kernel.dk>
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- May 31, 2024
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Waiman Long authored
Commit bf20ab53 ("blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW") attempts to revert the code change introduced by commit cd5ab1b0 ("blk-throttle: add .low interface"). However, it leaves behind the bps_conf[] and iops_conf[] fields in the throtl_grp structure which aren't set anywhere in the new blk-throttle.c code but are still being used by tg_prfill_limit() to display the limits in io.max. Now io.max always displays the following values if a block queue is used: <m>:<n> rbps=0 wbps=0 riops=0 wiops=0 Fix this problem by removing bps_conf[] and iops_conf[] and use bps[] and iops[] instead to complete the revert. Fixes: bf20ab53 ("blk-throttle: remove CONFIG_BLK_DEV_THROTTLING_LOW") Reported-by:
Justin Forbes <jforbes@redhat.com> Closes: https://github.com/containers/podman/issues/22701#issuecomment-2120627789 Signed-off-by:
Waiman Long <longman@redhat.com> Acked-by:
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- May 09, 2024
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Yu Kuai authored
Other cgroup policy like bfq, iocost are lazy-initialized when they are configured for the first time for the device, but blk-throttle is initialized unconditionally from blkcg_init_disk(). Delay initialization of blk-throttle as well, to save some cpu and memory overhead if it's not configured. Noted that once it's initialized, it can't be destroyed until disk removal, even if it's disabled. Signed-off-by:
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Yu Kuai authored
One the one hand, it's marked EXPERIMENTAL since 2017, and looks like there are no users since then, and no testers and no developers, it's just not active at all. On the other hand, even if the config is disabled, there are still many fields in throtl_grp and throtl_data and many functions that are only used for throtl low. At last, currently blk-throtl is initialized during disk initialization, and destroyed during disk removal, and it exposes many functions to be called directly from block layer. Remove throtl low to make code much more cleaner and follow up work much easier. Signed-off-by:
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- Aug 30, 2023
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Yu Kuai authored
'carryover_bytes/ios' can be negative, indicate that some bio is dispatched in advance within slice while configuration is updated. Print a huge value is not user-friendly. Signed-off-by:
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- Jun 25, 2023
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Jinke Han authored
After commit f382fb0b ("block: remove legacy IO schedulers"), blkio.throttle.io_serviced and blkio.throttle.io_service_bytes become the only stable io stats interface of cgroup v1, and these statistics are done in the blk-throttle code. But the current code only counts the bios that are actually throttled. When the user does not add the throttle limit, the io stats for cgroup v1 has nothing. I fix it according to the statistical method of v2, and made it count all ios accurately. Fixes: a7b36ee6 ("block: move blk-throtl fast path inline") Tested-by:
Andrea Righi <andrea.righi@canonical.com> Signed-off-by:
Jinke Han <hanjinke.666@bytedance.com> Acked-by:
Muchun Song <songmuchun@bytedance.com> Acked-by:
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- Sep 27, 2022
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Christoph Hellwig authored
Pass the gendisk to blk_throtl_cancel_bios as part of moving the blk-cgroup infrastructure to be gendisk based. Signed-off-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
Andreas Herrmann <aherrmann@suse.de> Acked-by:
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Christoph Hellwig authored
Pass the gendisk to blk_throtl_register_queue as part of moving the blk-cgroup infrastructure to be gendisk based. Signed-off-by:
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Christoph Hellwig authored
Pass the gendisk to blk_throtl_init and blk_throtl_exit as part of moving the blk-cgroup infrastructure to be gendisk based. Signed-off-by:
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- Sep 24, 2022
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Yu Kuai authored
"tg->has_rules" is extended to "tg->has_rules_iops/bps", thus bios that don't need to be throttled can be checked accurately. With this patch, bio will be throttled if: 1) Bio is read/write, and corresponding read/write iops limit exist. 2) If corresponding doesn't exist, corresponding bps limit exist and bio is not throttled before. Signed-off-by:
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Yu Kuai authored
Currently, "tg->has_rules" and "tg->flags & THROTL_TG_HAS_IOPS_LIMIT" both try to bypass bios that don't need to be throttled, however, they are a little redundant and both not perfect: 1) "tg->has_rules" only distinguish read and write, but not iops and bps limit. 2) "tg->flags & THROTL_TG_HAS_IOPS_LIMIT" only check if iops limit exist, read and write is not distinguished, and bps limit is not checked. tg->has_rules will extended to distinguish bps and iops in the following patch. There is no need to keep the flag. Signed-off-by:
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- Sep 12, 2022
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Yu Kuai authored
If new configuration is submitted while a bio is throttled, then new waiting time is recalculated regardless that the bio might already wait for some time: tg_conf_updated throtl_start_new_slice tg_update_disptime throtl_schedule_next_dispatch Then io hung can be triggered by always submmiting new configuration before the throttled bio is dispatched. Fix the problem by respecting the time that throttled bio already waited. In order to do that, add new fields to record how many bytes/io are waited, and use it to calculate wait time for throttled bio under new configuration. Some simple test: 1) cd /sys/fs/cgroup/blkio/ echo $$ > cgroup.procs echo "8:0 2048" > blkio.throttle.write_bps_device { sleep 2 echo "8:0 1024" > blkio.throttle.write_bps_device } & dd if=/dev/zero of=/dev/sda bs=8k count=1 oflag=direct 2) cd /sys/fs/cgroup/blkio/ echo $$ > cgroup.procs echo "8:0 1024" > blkio.throttle.write_bps_device { sleep 4 echo "8:0 2048" > blkio.throttle.write_bps_device } & dd if=/dev/zero of=/dev/sda bs=8k count=1 oflag=direct test results: io finish time before this patch with this patch 1) 10s 6s 2) 8s 6s Signed-off-by:Michal Koutný <mkoutny@suse.com> Acked-by:
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Yu Kuai authored
Test scripts: cd /sys/fs/cgroup/blkio/ echo "8:0 1024" > blkio.throttle.write_bps_device echo $$ > cgroup.procs dd if=/dev/zero of=/dev/sda bs=10k count=1 oflag=direct & dd if=/dev/zero of=/dev/sda bs=10k count=1 oflag=direct & Test result: 10240 bytes (10 kB, 10 KiB) copied, 10.0134 s, 1.0 kB/s 10240 bytes (10 kB, 10 KiB) copied, 10.0135 s, 1.0 kB/s The problem is that the second bio is finished after 10s instead of 20s. Root cause: 1) second bio will be flagged: __blk_throtl_bio while (true) { ... if (sq->nr_queued[rw]) -> some bio is throttled already break }; bio_set_flag(bio, BIO_THROTTLED); -> flag the bio 2) flagged bio will be dispatched without waiting: throtl_dispatch_tg tg_may_dispatch tg_with_in_bps_limit if (bps_limit == U64_MAX || bio_flagged(bio, BIO_THROTTLED)) *wait = 0; -> wait time is zero return true; commit 9f5ede3c ("block: throttle split bio in case of iops limit") support to count split bios for iops limit, thus it adds flagged bio checking in tg_with_in_bps_limit() so that split bios will only count once for bps limit, however, it introduce a new problem that io throttle won't work if multiple bios are throttled. In order to fix the problem, handle iops/bps limit in different ways: 1) for iops limit, there is no flag to record if the bio is throttled, and iops is always applied. 2) for bps limit, original bio will be flagged with BIO_BPS_THROTTLED, and io throttle will ignore bio with the flag. Noted this patch also remove the code to set flag in __bio_clone(), it's introduced in commit 111be883 ("block-throttle: avoid double charge"), and author thinks split bio can be resubmited and throttled again, which is wrong because split bio will continue to dispatch from caller. Fixes: 9f5ede3c ("block: throttle split bio in case of iops limit") Cc: <stable@vger.kernel.org> Signed-off-by:
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- Mar 18, 2022
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Yu Kuai authored
Throttled bios can't be issued after del_gendisk() is done, thus it's better to cancel them immediately rather than waiting for throttle is done. For example, if user thread is throttled with low bps while it's issuing large io, and the device is deleted. The user thread will wait for a long time for io to return. Signed-off-by:
Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20220318130144.1066064-4-ming.lei@redhat.com Signed-off-by:
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- Feb 17, 2022
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Ming Lei authored
Revert commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since we have another easier way to address this issue and get better iops throttling result. Acked-by:
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Ming Lei authored
We need to throttle split bio in case of IOPS limit even though the split bio has been marked as BIO_THROTTLED since block layer accounts split bio actually. If only throughput throttle is setup, no need to throttle any more if BIO_THROTTLED is set since we have accounted & considered the whole bio bytes already. Add one flag of THROTL_TG_HAS_IOPS_LIMIT for serving this purpose. Acked-by:
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Ming Lei authored
Commit 111be883 ("block-throttle: avoid double charge") marks bio as BIO_THROTTLED unconditionally if __blk_throtl_bio() is called on this bio, then this bio won't be called into __blk_throtl_bio() any more. This way is to avoid double charge in case of bio splitting. It is reasonable for read/write throughput limit, but not reasonable for IOPS limit because block layer provides io accounting against split bio. Chunguang Xu has already observed this issue and fixed it in commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios"). However, that patch only covers bio splitting in __blk_queue_split(), and we have other kind of bio splitting, such as bio_split() & submit_bio_noacct() and other ways. This patch tries to fix the issue in one generic way by always charging the bio for iops limit in blk_throtl_bio(). This way is reasonable: re-submission & fast-cloned bio is charged if it is submitted to same disk/queue, and BIO_THROTTLED will be cleared if bio->bi_bdev is changed. This new approach can get much more smooth/stable iops limit compared with commit 4f1e9630 ("blk-throtl: optimize IOPS throttle for large IO scenarios") since that commit can't throttle current split bios actually. Also this way won't cause new double bio iops charge in blk_throtl_dispatch_work_fn() in which blk_throtl_bio() won't be called any more. Reported-by:
Ning Li <lining2020x@163.com> Acked-by:
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- Oct 18, 2021
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Jens Axboe authored
Even if no policies are defined, we spend ~2% of the total IO time checking. Move the fast path inline. Acked-by:
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