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path: root/block/blk-iocost.c
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2023-08-09blk-iocost: fix queue stats accountingChengming Zhou
The q->stats->accounting is not only used by iocost, but iocost only increase this counter, never decrease it. So queue stats accounting will always enabled after using iocost once. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230804070609.31623-1-chengming.zhou@linux.dev Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-07-20blk-iocost: skip empty flush bio in iocostChengming Zhou
The flush bio may have data, may have no data (empty flush), we couldn't calculate cost for empty flush bio. So we'd better just skip it for now. Another side effect is that empty flush bio's bio_end_sector() is 0, cause iocg->cursor reset to 0, may break the cost calculation of other bios. This isn't good enough, since flush bio still consume the device bandwidth, but flush request is special, can be merged randomly in the flush state machine, we don't know how to calculate cost for it for now. Its completion time also has flaws, which may include the pre-flush or post-flush completion time, but I don't know if we need to fix that and how to fix it. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230720121441.1408522-1-chengming.zhou@linux.dev Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-26blk-iocost: move wbt_enable/disable_default() out of spinlockYu Kuai
There are following smatch warning: block/blk-wbt.c:843 wbt_init() warn: sleeping in atomic context ioc_qos_write() <- disables preempt -> wbt_enable_default() -> wbt_init() wbt_init() will be called from wbt_enable_default() if wbt is not initialized, currently this is only possible in blk_register_queue(), hence wbt_init() will never be called from iocost and this warning is false positive. However, we might support rq_qos destruction dynamically in the future, and it's better to prevent that, hence move wbt_enable_default() outside 'ioc->lock'. This is safe because queue is still freezed. Reported-by: Dan Carpenter <error27@gmail.com> Link: https://lore.kernel.org/lkml/Y+Ja5SRs886CEz7a@kadam/ Signed-off-by: Yu Kuai <yukuai3@huawei.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230527010644.647900-5-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-06-05blk-iocost: use spin_lock_irqsave in adjust_inuse_and_calc_costLi Nan
adjust_inuse_and_calc_cost() use spin_lock_irq() and IRQ will be enabled when unlock. DEADLOCK might happen if we have held other locks and disabled IRQ before invoking it. Fix it by using spin_lock_irqsave() instead, which can keep IRQ state consistent with before when unlock. ================================ WARNING: inconsistent lock state 5.10.0-02758-g8e5f91fd772f #26 Not tainted -------------------------------- inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage. kworker/2:3/388 [HC0[0]:SC0[0]:HE0:SE1] takes: ffff888118c00c28 (&bfqd->lock){?.-.}-{2:2}, at: spin_lock_irq ffff888118c00c28 (&bfqd->lock){?.-.}-{2:2}, at: bfq_bio_merge+0x141/0x390 {IN-HARDIRQ-W} state was registered at: __lock_acquire+0x3d7/0x1070 lock_acquire+0x197/0x4a0 __raw_spin_lock_irqsave _raw_spin_lock_irqsave+0x3b/0x60 bfq_idle_slice_timer_body bfq_idle_slice_timer+0x53/0x1d0 __run_hrtimer+0x477/0xa70 __hrtimer_run_queues+0x1c6/0x2d0 hrtimer_interrupt+0x302/0x9e0 local_apic_timer_interrupt __sysvec_apic_timer_interrupt+0xfd/0x420 run_sysvec_on_irqstack_cond sysvec_apic_timer_interrupt+0x46/0xa0 asm_sysvec_apic_timer_interrupt+0x12/0x20 irq event stamp: 837522 hardirqs last enabled at (837521): [<ffffffff84b9419d>] __raw_spin_unlock_irqrestore hardirqs last enabled at (837521): [<ffffffff84b9419d>] _raw_spin_unlock_irqrestore+0x3d/0x40 hardirqs last disabled at (837522): [<ffffffff84b93fa3>] __raw_spin_lock_irq hardirqs last disabled at (837522): [<ffffffff84b93fa3>] _raw_spin_lock_irq+0x43/0x50 softirqs last enabled at (835852): [<ffffffff84e00558>] __do_softirq+0x558/0x8ec softirqs last disabled at (835845): [<ffffffff84c010ff>] asm_call_irq_on_stack+0xf/0x20 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&bfqd->lock); <Interrupt> lock(&bfqd->lock); *** DEADLOCK *** 3 locks held by kworker/2:3/388: #0: ffff888107af0f38 ((wq_completion)kthrotld){+.+.}-{0:0}, at: process_one_work+0x742/0x13f0 #1: ffff8881176bfdd8 ((work_completion)(&td->dispatch_work)){+.+.}-{0:0}, at: process_one_work+0x777/0x13f0 #2: ffff888118c00c28 (&bfqd->lock){?.-.}-{2:2}, at: spin_lock_irq #2: ffff888118c00c28 (&bfqd->lock){?.-.}-{2:2}, at: bfq_bio_merge+0x141/0x390 stack backtrace: CPU: 2 PID: 388 Comm: kworker/2:3 Not tainted 5.10.0-02758-g8e5f91fd772f #26 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 Workqueue: kthrotld blk_throtl_dispatch_work_fn Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 print_usage_bug valid_state mark_lock_irq.cold+0x32/0x3a mark_lock+0x693/0xbc0 mark_held_locks+0x9e/0xe0 __trace_hardirqs_on_caller lockdep_hardirqs_on_prepare.part.0+0x151/0x360 trace_hardirqs_on+0x5b/0x180 __raw_spin_unlock_irq _raw_spin_unlock_irq+0x24/0x40 spin_unlock_irq adjust_inuse_and_calc_cost+0x4fb/0x970 ioc_rqos_merge+0x277/0x740 __rq_qos_merge+0x62/0xb0 rq_qos_merge bio_attempt_back_merge+0x12c/0x4a0 blk_mq_sched_try_merge+0x1b6/0x4d0 bfq_bio_merge+0x24a/0x390 __blk_mq_sched_bio_merge+0xa6/0x460 blk_mq_sched_bio_merge blk_mq_submit_bio+0x2e7/0x1ee0 __submit_bio_noacct_mq+0x175/0x3b0 submit_bio_noacct+0x1fb/0x270 blk_throtl_dispatch_work_fn+0x1ef/0x2b0 process_one_work+0x83e/0x13f0 process_scheduled_works worker_thread+0x7e3/0xd80 kthread+0x353/0x470 ret_from_fork+0x1f/0x30 Fixes: b0853ab4a238 ("blk-iocost: revamp in-period donation snapbacks") Signed-off-by: Li Nan <linan122@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Yu Kuai <yukuai3@huawei.com> Link: https://lore.kernel.org/r/20230527091904.3001833-1-linan666@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-04-13blkcg: Restructure blkg_conf_prep() and friendsTejun Heo
We want to support lazy init of rq-qos policies so that iolatency is enabled lazily on configuration instead of gendisk initialization. The way blkg config helpers are structured now is a bit awkward for that. Let's restructure: * blkcg_conf_open_bdev() is renamed to blkg_conf_open_bdev(). The blkcg_ prefix was used because the bdev opening step is blkg-independent. However, the distinction is too subtle and confuses more than helps. Let's switch to blkg prefix so that it's consistent with the type and other helper names. * struct blkg_conf_ctx now remembers the original input string and is always initialized by the new blkg_conf_init(). * blkg_conf_open_bdev() is updated to take a pointer to blkg_conf_ctx like blkg_conf_prep() and can be called multiple times safely. Instead of modifying the double pointer to input string directly, blkg_conf_open_bdev() now sets blkg_conf_ctx->body. * blkg_conf_finish() is renamed to blkg_conf_exit() for symmetry and now must be called on all blkg_conf_ctx's which were initialized with blkg_conf_init(). Combined, this allows the users to either open the bdev first or do it altogether with blkg_conf_prep() which will help implementing lazy init of rq-qos policies. blkg_conf_init/exit() will also be used implement synchronization against device removal. This is necessary because iolat / iocost are configured through cgroupfs instead of one of the files under /sys/block/DEVICE. As cgroupfs operations aren't synchronized with block layer, the lazy init and other configuration operations may race against device removal. This patch makes blkg_conf_init/exit() used consistently for all cgroup-orginating configurations making them a good place to implement explicit synchronization. Users are updated accordingly. No behavior change is intended by this patch. v2: bfq wasn't updated in v1 causing a build error. Fixed. v3: Update the description to include future use of blkg_conf_init/exit() as synchronization points. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Yu Kuai <yukuai1@huaweicloud.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230413000649.115785-3-tj@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-28blk-iocost: Pass gendisk to ioc_refresh_paramsBreno Leitao
Current kernel (d2980d8d826554fa6981d621e569a453787472f8) crashes when blk_iocost_init for `nvme1` disk. BUG: kernel NULL pointer dereference, address: 0000000000000050 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page blk_iocost_init (include/asm-generic/qspinlock.h:128 include/linux/spinlock.h:203 include/linux/spinlock_api_smp.h:158 include/linux/spinlock.h:400 block/blk-iocost.c:2884) ioc_qos_write (block/blk-iocost.c:3198) ? kretprobe_perf_func (kernel/trace/trace_kprobe.c:1566) ? kernfs_fop_write_iter (include/linux/slab.h:584 fs/kernfs/file.c:311) ? __kmem_cache_alloc_node (mm/slab.h:? mm/slub.c:3452 mm/slub.c:3491) ? _copy_from_iter (arch/x86/include/asm/uaccess_64.h:46 arch/x86/include/asm/uaccess_64.h:52 lib/iov_iter.c:183 lib/iov_iter.c:628) ? kretprobe_dispatcher (kernel/trace/trace_kprobe.c:1693) cgroup_file_write (kernel/cgroup/cgroup.c:4061) kernfs_fop_write_iter (fs/kernfs/file.c:334) vfs_write (include/linux/fs.h:1849 fs/read_write.c:491 fs/read_write.c:584) ksys_write (fs/read_write.c:637) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) This happens because ioc_refresh_params() is being called without a properly initialized ioc->rqos, which is happening later in the callee side. ioc_refresh_params() -> ioc_autop_idx() tries to access ioc->rqos.disk->queue but ioc->rqos.disk is NULL, causing the BUG above. Create function, called ioc_refresh_params_disk(), that is similar to ioc_refresh_params() but where the "struct gendisk" could be passed as an explicit argument. This function will be called when ioc->rqos.disk is not initialized. Fixes: ce57b558604e ("blk-rq-qos: make rq_qos_add and rq_qos_del more useful") Signed-off-by: Breno Leitao <leitao@debian.org> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230228111654.1778120-1-leitao@debian.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-14Revert "blk-cgroup: pin the gendisk in struct blkcg_gq"Christoph Hellwig
This reverts commit 84d7d462b16dd5f0bf7c7ca9254bf81db2c952a2. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20230214183308.1658775-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-cgroup: pass a gendisk to pd_alloc_fnChristoph Hellwig
No need to the request_queue here, pass a gendisk and extract the node ids from that. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-18-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-cgroup: pass a gendisk to blkcg_{de,}activate_policyChristoph Hellwig
Prepare for storing the blkcg information in the gendisk instead of the request_queue. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-17-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-rq-qos: store a gendisk instead of request_queue in struct rq_qosChristoph Hellwig
This is what about half of the users already want, and it's only going to grow more. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-16-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-rq-qos: constify rq_qos_opsChristoph Hellwig
These op vectors are constant, so mark them const. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-15-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-rq-qos: make rq_qos_add and rq_qos_del more usefulChristoph Hellwig
Switch to passing a gendisk, and make rq_qos_add initialize all required fields and drop the not required q argument from rq_qos_del. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-14-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-wbt: pass a gendisk to wbt_{enable,disable}_defaultChristoph Hellwig
Pass a gendisk to wbt_enable_default and wbt_disable_default to prepare for phasing out usage of the request_queue in the blk-cgroup code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-02-03blk-cgroup: pin the gendisk in struct blkcg_gqChristoph Hellwig
Currently each blkcg_gq holds a request_queue reference, which is what is used in the policies. But a lot of these interfaces will move over to use a gendisk, so store a disk in struct blkcg_gq and hold a reference to it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20230203150400.3199230-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29blk-iocost: change div64_u64 to DIV64_U64_ROUND_UP in ioc_refresh_params()Li Nan
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.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29blk-iocost: fix divide by 0 error in calc_lcoefs()Li Nan
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.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29blk-iocost: read params inside lock in sysfs apisYu Kuai
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.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29blk-iocost: don't allow to configure bio based deviceYu Kuai
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.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29blk-iocost: check return value of match_u64()Yu Kuai
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.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2023-01-29blk-iocost: avoid 64-bit division in ioc_timer_fnArnd Bergmann
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.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-25treewide: Convert del_timer*() to timer_shutdown*()Steven Rostedt (Google)
Due to several bugs caused by timers being re-armed after they are shutdown and just before they are freed, a new state of timers was added called "shutdown". After a timer is set to this state, then it can no longer be re-armed. The following script was run to find all the trivial locations where del_timer() or del_timer_sync() is called in the same function that the object holding the timer is freed. It also ignores any locations where the timer->function is modified between the del_timer*() and the free(), as that is not considered a "trivial" case. This was created by using a coccinelle script and the following commands: $ cat timer.cocci @@ expression ptr, slab; identifier timer, rfield; @@ ( - del_timer(&ptr->timer); + timer_shutdown(&ptr->timer); | - del_timer_sync(&ptr->timer); + timer_shutdown_sync(&ptr->timer); ) ... when strict when != ptr->timer ( kfree_rcu(ptr, rfield); | kmem_cache_free(slab, ptr); | kfree(ptr); ) $ spatch timer.cocci . > /tmp/t.patch $ patch -p1 < /tmp/t.patch Link: https://lore.kernel.org/lkml/20221123201306.823305113@linutronix.de/ Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org> Acked-by: Pavel Machek <pavel@ucw.cz> [ LED ] Acked-by: Kalle Valo <kvalo@kernel.org> [ wireless ] Acked-by: Paolo Abeni <pabeni@redhat.com> [ networking ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-12-14block/blk-iocost (gcc13): keep large values in a new enumJiri Slaby (SUSE)
Since gcc13, each member of an enum has the same type as the enum [1]. And that is inherited from its members. Provided: VTIME_PER_SEC_SHIFT = 37, VTIME_PER_SEC = 1LLU << VTIME_PER_SEC_SHIFT, ... AUTOP_CYCLE_NSEC = 10LLU * NSEC_PER_SEC, the named type is unsigned long. This generates warnings with gcc-13: block/blk-iocost.c: In function 'ioc_weight_prfill': block/blk-iocost.c:3037:37: error: format '%u' expects argument of type 'unsigned int', but argument 4 has type 'long unsigned int' block/blk-iocost.c: In function 'ioc_weight_show': block/blk-iocost.c:3047:34: error: format '%u' expects argument of type 'unsigned int', but argument 3 has type 'long unsigned int' So split the anonymous enum with large values to a separate enum, so that they don't affect other members. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=36113 Cc: Martin Liska <mliska@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Josef Bacik <josef@toxicpanda.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: cgroups@vger.kernel.org Cc: linux-block@vger.kernel.org Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org> Link: https://lore.kernel.org/r/20221213120826.17446-1-jirislaby@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-01blk-iocost: Correct comment in blk_iocost_initKemeng Shi
There is no iocg_pd_init function. The pd_alloc_fn function pointer of iocost policy is set with ioc_pd_init. Just correct it. Signed-off-by: Kemeng Shi <shikemeng@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221018121932.10792-6-shikemeng@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-01blk-iocost: Remove vrate member in struct ioc_nowKemeng Shi
If we trace vtime_base_rate instead of vtime_rate, there is nowhere which accesses now->vrate except function ioc_now using now->vrate locally. Just remove it. Signed-off-by: Kemeng Shi <shikemeng@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221018121932.10792-5-shikemeng@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-01blk-iocost: Trace vtime_base_rate instead of vtime_rateKemeng Shi
Since commit ac33e91e2daca ("blk-iocost: implement vtime loss compensation") rename original vtime_rate to vtime_base_rate and current vtime_rate is original vtime_rate with compensation. The current rate showed in tracepoint is mixed with vtime_rate and vtime_base_rate: 1) In function ioc_adjust_base_vrate, the first trace_iocost_ioc_vrate_adj shows vtime_rate, the second trace_iocost_ioc_vrate_adj shows vtime_base_rate. 2) In function iocg_activate shows vtime_rate by calling TRACE_IOCG_PATH(iocg_activate... 3) In function ioc_check_iocgs shows vtime_rate by calling TRACE_IOCG_PATH(iocg_idle... Trace vtime_base_rate instead of vtime_rate as: 1) Before commit ac33e91e2daca ("blk-iocost: implement vtime loss compensation"), the traced rate is without compensation, so still show rate without compensation. 2) The vtime_base_rate is more stable while vtime_rate heavily depends on excess budeget on current period which may change abruptly in next period. Signed-off-by: Kemeng Shi <shikemeng@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221018121932.10792-4-shikemeng@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-01blk-iocost: Reset vtime_base_rate in ioc_refresh_paramsKemeng Shi
Since commit ac33e91e2daca("blk-iocost: implement vtime loss compensation") split vtime_rate into vtime_rate and vtime_base_rate, we need reset both vtime_base_rate and vtime_rate when device parameters are refreshed. If vtime_base_rate is no reset here, vtime_rate will be overwritten with old vtime_base_rate soon in ioc_refresh_vrate. Signed-off-by: Kemeng Shi <shikemeng@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221018121932.10792-3-shikemeng@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-12-01blk-iocost: Fix typo in commentKemeng Shi
soley -> solely Signed-off-by: Kemeng Shi <shikemeng@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221018121932.10792-2-shikemeng@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-iocost: read 'ioc->params' inside 'ioc->lock' in ioc_timer_fn()Yu Kuai
'ioc->params' is updated in ioc_refresh_params(), which is proteced by 'ioc->lock', however, ioc_timer_fn() read params outside the lock. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221012094035.390056-5-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-iocost: prevent configuration update concurrent with io throttlingYu Kuai
This won't cause any severe problem currently, however, this doesn't seems appropriate: 1) 'ioc->params' is read from multiple places without holding 'ioc->lock', unexpected value might be read if writing it concurrently. 2) If configuration is changed while io is throttling, the functionality might be affected. For example, if module params is updated and cost becomes smaller, waiting for timer that is caculated under old configuration is not appropriate. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221012094035.390056-4-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-iocost: don't release 'ioc->lock' while updating paramsYu Kuai
ioc_qos_write() and ioc_cost_model_write() are the same: 1) hold lock to read 'ioc->params' to local variable; 2) update params to local variable without lock; 3) hold lock to write local variable to 'ioc->params'; In theroy, if user updates params concurrenty, the params might be lost: t1: update params a t2: update params b spin_lock_irq(&ioc->lock); memcpy(qos, ioc->params.qos, sizeof(qos)) spin_unlock_irq(&ioc->lock); qos[a] = xxx; spin_lock_irq(&ioc->lock); memcpy(qos, ioc->params.qos, sizeof(qos)) spin_unlock_irq(&ioc->lock); qos[b] = xxx; spin_lock_irq(&ioc->lock); memcpy(ioc->params.qos, qos, sizeof(qos)); ioc_refresh_params(ioc, true); spin_unlock_irq(&ioc->lock); spin_lock_irq(&ioc->lock); // updates of a will be lost memcpy(ioc->params.qos, qos, sizeof(qos)); ioc_refresh_params(ioc, true); spin_unlock_irq(&ioc->lock); Althrough this is not common case, the problem can by fixed easily by holding the lock through the read, update, write process. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221012094035.390056-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-10-23blk-iocost: disable writeback throttlingYu Kuai
Commit b5dc5d4d1f4f ("block,bfq: Disable writeback throttling") disable wbt for bfq, because different write-throttling heuristics should not work together. For the same reason, wbt and iocost should not work together as well, unless admin really want to do that, dispite that performance is affected. Signed-off-by: Yu Kuai <yukuai3@huawei.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20221012094035.390056-2-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-26blk-cgroup: pass a gendisk to blkcg_schedule_throttleChristoph Hellwig
Pass the gendisk to blkcg_schedule_throttle as part of moving the blk-cgroup infrastructure to be gendisk based. Remove the unused !BLK_CGROUP stub while we're at it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220921180501.1539876-17-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-26blk-iocost: cleanup ioc_qos_writeChristoph Hellwig
Use a local disk variable instead of retrieving the disk and request_queue over and over by various means. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220921180501.1539876-12-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-26blk-iocost: pass a gendisk to blk_iocost_initChristoph Hellwig
Pass the gendisk to blk_iocost_init 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: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220921180501.1539876-11-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-26blk-iocost: simplify ioc_nameChristoph Hellwig
Just directly dereference the disk name instead of going through multiple hoops to find the same value. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220921180501.1539876-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-09-20blk-iocost: Remove unnecessary (void*) conversionsLi zeming
The key pointer is void and hence does not need an explicit cast. Signed-off-by: Li zeming <zeming@nfschina.com> Link: https://lore.kernel.org/r/20220919012825.2936-1-zeming@nfschina.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-07-20block: don't allow the same type rq_qos add more than onceJinke Han
In our test of iocost, we encountered some list add/del corruptions of inner_walk list in ioc_timer_fn. The reason can be described as follows: cpu 0 cpu 1 ioc_qos_write ioc_qos_write ioc = q_to_ioc(queue); if (!ioc) { ioc = kzalloc(); ioc = q_to_ioc(queue); if (!ioc) { ioc = kzalloc(); ... rq_qos_add(q, rqos); } ... rq_qos_add(q, rqos); ... } When the io.cost.qos file is written by two cpus concurrently, rq_qos may be added to one disk twice. In that case, there will be two iocs enabled and running on one disk. They own different iocgs on their active list. In the ioc_timer_fn function, because of the iocgs from two iocs have the same root iocg, the root iocg's walk_list may be overwritten by each other and this leads to list add/del corruptions in building or destroying the inner_walk list. And so far, the blk-rq-qos framework works in case that one instance for one type rq_qos per queue by default. This patch make this explicit and also fix the crash above. Signed-off-by: Jinke Han <hanjinke.666@bytedance.com> Reviewed-by: Muchun Song <songmuchun@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20220720093616.70584-1-hanjinke.666@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-06-27blk-iocost: Simplify ioc_rqos_done()Bart Van Assche
Leave out the superfluous "& REQ_OP_MASK" code. The definition of req_op() shows that that code is superfluous: #define req_op(req) ((req)->cmd_flags & REQ_OP_MASK) Compile-tested only. Cc: Tejun Heo <tj@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20220615225549.1054905-2-bvanassche@acm.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-05-23Merge tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block updates from Jens Axboe: "Here are the core block changes for 5.19. This contains: - blk-throttle accounting fix (Laibin) - Series removing redundant assignments (Michal) - Expose bio cache via the bio_set, so that DM can use it (Mike) - Finish off the bio allocation interface cleanups by dealing with the weirdest member of the family. bio_kmalloc combines a kmalloc for the bio and bio_vecs with a hidden bio_init call and magic cleanup semantics (Christoph) - Clean up the block layer API so that APIs consumed by file systems are (almost) only struct block_device based, so that file systems don't have to poke into block layer internals like the request_queue (Christoph) - Clean up the blk_execute_rq* API (Christoph) - Clean up various lose end in the blk-cgroup code to make it easier to follow in preparation of reworking the blkcg assignment for bios (Christoph) - Fix use-after-free issues in BFQ when processes with merged queues get moved to different cgroups (Jan) - BFQ fixes (Jan) - Various fixes and cleanups (Bart, Chengming, Fanjun, Julia, Ming, Wolfgang, me)" * tag 'for-5.19/block-2022-05-22' of git://git.kernel.dk/linux-block: (83 commits) blk-mq: fix typo in comment bfq: Remove bfq_requeue_request_body() bfq: Remove superfluous conversion from RQ_BIC() bfq: Allow current waker to defend against a tentative one bfq: Relax waker detection for shared queues blk-cgroup: delete rcu_read_lock_held() WARN_ON_ONCE() blk-throttle: Set BIO_THROTTLED when bio has been throttled blk-cgroup: Remove unnecessary rcu_read_lock/unlock() blk-cgroup: always terminate io.stat lines block, bfq: make bfq_has_work() more accurate block, bfq: protect 'bfqd->queued' by 'bfqd->lock' block: cleanup the VM accounting in submit_bio block: Fix the bio.bi_opf comment block: reorder the REQ_ flags blk-iocost: combine local_stat and desc_stat to stat block: improve the error message from bio_check_eod block: allow passing a NULL bdev to bio_alloc_clone/bio_init_clone block: remove superfluous calls to blkcg_bio_issue_init kthread: unexport kthread_blkcg blk-cgroup: cleanup blkcg_maybe_throttle_current ...
2022-05-17blk-cgroup: always terminate io.stat linesWolfgang Bumiller
With the removal of seq_get_buf in blkcg_print_one_stat, we cannot make adding the newline conditional on there being relevant stats because the name was already written out unconditionally. Otherwise we may end up with multiple device names in one line which is confusing and doesn't follow the nested-keyed file format. Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com> Fixes: 252c651a4c85 ("blk-cgroup: stop using seq_get_buf") Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220111083159.42340-1-w.bumiller@proxmox.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-05-11blk-iocost: combine local_stat and desc_stat to statChengming Zhou
When we flush usage, wait, indebt stat in iocg_flush_stat(), we use local_stat and desc_stat, which has no point since the leaf iocg only has local_stat and the inner iocg only has desc_stat. Also we don't need to flush percpu abs_vusage for these inner iocgs. This patch combine local_stat and desc_stat to stat, only flush percpu abs_vusage for active leaf iocgs, then build inner walk list to propagate. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220510034757.21761-1-zhouchengming@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-04-27iocost: don't reset the inuse weight of under-weighted debtorsTejun Heo
When an iocg is in debt, its inuse weight is owned by debt handling and should stay at 1. This invariant was broken when determining the amount of surpluses at the beginning of donation calculation - when an iocg's hierarchical weight is too low, the iocg is excluded from donation calculation and its inuse is reset to its active regardless of its indebtedness, triggering warnings like the following: WARNING: CPU: 5 PID: 0 at block/blk-iocost.c:1416 iocg_kick_waitq+0x392/0x3a0 ... RIP: 0010:iocg_kick_waitq+0x392/0x3a0 Code: 00 00 be ff ff ff ff 48 89 4d a8 e8 98 b2 70 00 48 8b 4d a8 85 c0 0f 85 4a fe ff ff 0f 0b e9 43 fe ff ff 0f 0b e9 4d fe ff ff <0f> 0b e9 50 fe ff ff e8 a2 ae 70 00 66 90 0f 1f 44 00 00 55 48 89 RSP: 0018:ffffc90000200d08 EFLAGS: 00010016 ... <IRQ> ioc_timer_fn+0x2e0/0x1470 call_timer_fn+0xa1/0x2c0 ... As this happens only when an iocg's hierarchical weight is negligible, its impact likely is limited to triggering the warnings. Fix it by skipping resetting inuse of under-weighted debtors. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Rik van Riel <riel@surriel.com> Fixes: c421a3eb2e27 ("blk-iocost: revamp debt handling") Cc: stable@vger.kernel.org # v5.10+ Link: https://lore.kernel.org/r/YmjODd4aif9BzFuO@slm.duckdns.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-02-11block: partition include/linux/blk-cgroup.hMing Lei
Partition include/linux/blk-cgroup.h into two parts: one is public part, the other is block layer private part. Suggested by Christoph Hellwig. Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20220211101149.2368042-4-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-12-14iocost: Fix divide-by-zero on donation from low hweight cgroupTejun Heo
The donation calculation logic assumes that the donor has non-zero after-donation hweight, so the lowest active hweight a donating cgroup can have is 2 so that it can donate 1 while keeping the other 1 for itself. Earlier, we only donated from cgroups with sizable surpluses so this condition was always true. However, with the precise donation algorithm implemented, f1de2439ec43 ("blk-iocost: revamp donation amount determination") made the donation amount calculation exact enabling even low hweight cgroups to donate. This means that in rare occasions, a cgroup with active hweight of 1 can enter donation calculation triggering the following warning and then a divide-by-zero oops. WARNING: CPU: 4 PID: 0 at block/blk-iocost.c:1928 transfer_surpluses.cold+0x0/0x53 [884/94867] ... RIP: 0010:transfer_surpluses.cold+0x0/0x53 Code: 92 ff 48 c7 c7 28 d1 ab b5 65 48 8b 34 25 00 ae 01 00 48 81 c6 90 06 00 00 e8 8b 3f fe ff 48 c7 c0 ea ff ff ff e9 95 ff 92 ff <0f> 0b 48 c7 c7 30 da ab b5 e8 71 3f fe ff 4c 89 e8 4d 85 ed 74 0 4 ... Call Trace: <IRQ> ioc_timer_fn+0x1043/0x1390 call_timer_fn+0xa1/0x2c0 __run_timers.part.0+0x1ec/0x2e0 run_timer_softirq+0x35/0x70 ... iocg: invalid donation weights in /a/b: active=1 donating=1 after=0 Fix it by excluding cgroups w/ active hweight < 2 from donating. Excluding these extreme low hweight donations shouldn't affect work conservation in any meaningful way. Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: f1de2439ec43 ("blk-iocost: revamp donation amount determination") Cc: stable@vger.kernel.org # v5.10+ Link: https://lore.kernel.org/r/Ybfh86iSvpWKxhVM@slm.duckdns.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18block: convert the rest of block to bdev_get_queuePavel Begunkov
Convert bdev->bd_disk->queue to bdev_get_queue(), it's uses a cached queue pointer and so is faster. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/addf6ea988c04213697ba3684c853e4ed7642a39.1634219547.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-30Merge tag 'for-5.15/block-2021-08-30' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block updates from Jens Axboe: "Nothing major in here - lots of good cleanups and tech debt handling, which is also evident in the diffstats. In particular: - Add disk sequence numbers (Matteo) - Discard merge fix (Ming) - Relax disk zoned reporting restrictions (Niklas) - Bio error handling zoned leak fix (Pavel) - Start of proper add_disk() error handling (Luis, Christoph) - blk crypto fix (Eric) - Non-standard GPT location support (Dmitry) - IO priority improvements and cleanups (Damien)o - blk-throtl improvements (Chunguang) - diskstats_show() stack reduction (Abd-Alrhman) - Loop scheduler selection (Bart) - Switch block layer to use kmap_local_page() (Christoph) - Remove obsolete disk_name helper (Christoph) - block_device refcounting improvements (Christoph) - Ensure gendisk always has a request queue reference (Christoph) - Misc fixes/cleanups (Shaokun, Oliver, Guoqing)" * tag 'for-5.15/block-2021-08-30' of git://git.kernel.dk/linux-block: (129 commits) sg: pass the device name to blk_trace_setup block, bfq: cleanup the repeated declaration blk-crypto: fix check for too-large dun_bytes blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN blk-zoned: allow zone management send operations without CAP_SYS_ADMIN block: mark blkdev_fsync static block: refine the disk_live check in del_gendisk mmc: sdhci-tegra: Enable MMC_CAP2_ALT_GPT_TEGRA mmc: block: Support alternative_gpt_sector() operation partitions/efi: Support non-standard GPT location block: Add alternative_gpt_sector() operation bio: fix page leak bio_add_hw_page failure block: remove CONFIG_DEBUG_BLOCK_EXT_DEVT block: remove a pointless call to MINOR() in device_add_disk null_blk: add error handling support for add_disk() virtio_blk: add error handling support for add_disk() block: add error handling for device_add_disk / add_disk block: return errors from disk_alloc_events block: return errors from blk_integrity_add block: call blk_register_queue earlier in device_add_disk ...
2021-08-16blk-cgroup: stop using seq_get_bufChristoph Hellwig
seq_get_buf is a crutch that undoes all the memory safety of the seq_file interface. Use the normal seq_printf interfaces instead. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210810152623.1796144-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09blk-iocost: fix lockdep warning on blkcg->lockMing Lei
blkcg->lock depends on q->queue_lock which may depend on another driver lock required in irq context, one example is dm-thin: Chain exists of: &pool->lock#3 --> &q->queue_lock --> &blkcg->lock Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&blkcg->lock); local_irq_disable(); lock(&pool->lock#3); lock(&q->queue_lock); <Interrupt> lock(&pool->lock#3); Fix the issue by using spin_lock_irq(&blkcg->lock) in ioc_weight_write(). Cc: Tejun Heo <tj@kernel.org> Reported-by: Bruno Goncalves <bgoncalv@redhat.com> Link: https://lore.kernel.org/linux-block/CA+QYu4rzz6079ighEanS3Qq_Dmnczcf45ZoJoHKVLVATTo1e4Q@mail.gmail.com/T/#u Signed-off-by: Ming Lei <ming.lei@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20210803070608.1766400-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-07-27blk-iocost: fix operation ordering in iocg_wake_fn()Tejun Heo
iocg_wake_fn() open-codes wait_queue_entry removal and wakeup because it wants the wq_entry to be always removed whether it ended up waking the task or not. finish_wait() tests whether wq_entry needs removal without grabbing the wait_queue lock and expects the waker to use list_del_init_careful() after all waking operations are complete, which iocg_wake_fn() didn't do. The operation order was wrong and the regular list_del_init() was used. The result is that if a waiter wakes up racing the waker, it can free pop the wq_entry off stack before the waker is still looking at it, which can lead to a backtrace like the following. [7312084.588951] general protection fault, probably for non-canonical address 0x586bf4005b2b88: 0000 [#1] SMP ... [7312084.647079] RIP: 0010:queued_spin_lock_slowpath+0x171/0x1b0 ... [7312084.858314] Call Trace: [7312084.863548] _raw_spin_lock_irqsave+0x22/0x30 [7312084.872605] try_to_wake_up+0x4c/0x4f0 [7312084.880444] iocg_wake_fn+0x71/0x80 [7312084.887763] __wake_up_common+0x71/0x140 [7312084.895951] iocg_kick_waitq+0xe8/0x2b0 [7312084.903964] ioc_rqos_throttle+0x275/0x650 [7312084.922423] __rq_qos_throttle+0x20/0x30 [7312084.930608] blk_mq_make_request+0x120/0x650 [7312084.939490] generic_make_request+0xca/0x310 [7312084.957600] submit_bio+0x173/0x200 [7312084.981806] swap_readpage+0x15c/0x240 [7312084.989646] read_swap_cache_async+0x58/0x60 [7312084.998527] swap_cluster_readahead+0x201/0x320 [7312085.023432] swapin_readahead+0x2df/0x450 [7312085.040672] do_swap_page+0x52f/0x820 [7312085.058259] handle_mm_fault+0xa16/0x1420 [7312085.066620] do_page_fault+0x2c6/0x5c0 [7312085.074459] page_fault+0x2f/0x40 Fix it by switching to list_del_init_careful() and putting it at the end. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Rik van Riel <riel@surriel.com> Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org # v5.4+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-05-11blk-iocost: fix weight updates of inner active iocgsTejun Heo
When the weight of an active iocg is updated, weight_updated() is called which in turn calls __propagate_weights() to update the active and inuse weights so that the effective hierarchical weights are update accordingly. The current implementation is incorrect for inner active nodes. For an active leaf iocg, inuse can be any value between 1 and active and the difference represents how much the iocg is donating. When weight is updated, as long as inuse is clamped between 1 and the new weight, we're alright and this is what __propagate_weights() currently implements. However, that's not how an active inner node's inuse is set. An inner node's inuse is solely determined by the ratio between the sums of inuse's and active's of its children - ie. they're results of propagating the leaves' active and inuse weights upwards. __propagate_weights() incorrectly applies the same clamping as for a leaf when an active inner node's weight is updated. Consider a hierarchy which looks like the following with saturating workloads in AA and BB. R / \ A B | | AA BB 1. For both A and B, active=100, inuse=100, hwa=0.5, hwi=0.5. 2. echo 200 > A/io.weight 3. __propagate_weights() update A's active to 200 and leave inuse at 100 as it's already between 1 and the new active, making A:active=200, A:inuse=100. As R's active_sum is updated along with A's active, A:hwa=2/3, B:hwa=1/3. However, because the inuses didn't change, the hwi's remain unchanged at 0.5. 4. The weight of A is now twice that of B but AA and BB still have the same hwi of 0.5 and thus are doing the same amount of IOs. Fix it by making __propgate_weights() always calculate the inuse of an active inner iocg based on the ratio of child_inuse_sum to child_active_sum. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Dan Schatzberg <dschatzberg@fb.com> Fixes: 7caa47151ab2 ("blkcg: implement blk-iocost") Cc: stable@vger.kernel.org # v5.4+ Link: https://lore.kernel.org/r/YJsxnLZV1MnBcqjj@slm.duckdns.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-11-24 20:40:11 +0000