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[ Upstream commit 2a427b49d02995ea4a6ff93a1432c40fa4d36821 ]
When iocg_kick_delay() is called from a CPU different than the one which set
the delay, @now may be in the past of @iocg->delay_at leading to the
following warning:
UBSAN: shift-out-of-bounds in block/blk-iocost.c:1359:23
shift exponent 18446744073709 is too large for 64-bit type 'u64' (aka 'unsigned long long')
...
Call Trace:
<TASK>
dump_stack_lvl+0x79/0xc0
__ubsan_handle_shift_out_of_bounds+0x2ab/0x300
iocg_kick_delay+0x222/0x230
ioc_rqos_merge+0x1d7/0x2c0
__rq_qos_merge+0x2c/0x80
bio_attempt_back_merge+0x83/0x190
blk_attempt_plug_merge+0x101/0x150
blk_mq_submit_bio+0x2b1/0x720
submit_bio_noacct_nocheck+0x320/0x3e0
__swap_writepage+0x2ab/0x9d0
The underflow itself doesn't really affect the behavior in any meaningful
way; however, the past timestamp may exaggerate the delay amount calculated
later in the code, which shouldn't be a material problem given the nature of
the delay mechanism.
If @now is in the past, this CPU is racing another CPU which recently set up
the delay and there's nothing this CPU can contribute w.r.t. the delay.
Let's bail early from iocg_kick_delay() in such cases.
Reported-by: Breno Leitão <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 5160a5a53c0c ("blk-iocost: implement delay adjustment hysteresis")
Link: https://lore.kernel.org/r/ZVvc9L_CYk5LO1fT@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 8d211554679d0b23702bd32ba04aeac0c1c4f660 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit ff1cc97b1f4c10db224f276d9615b22835b8c424 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5f2779dfa7b8cc7dfd4a1b6586d86e0d193266f3 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 984af1e66b4126cf145153661cc24c213e2ec231 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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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>
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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>
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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>
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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>
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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>
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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>
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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>
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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
...
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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>
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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>
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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>
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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>
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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>
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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>
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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
...
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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>
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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>
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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>
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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>
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ioc_adjust_base_vrate() ignored vrate_min when rq_wait_pct indicates that
there is QD contention. The reasoning was that QD depletion always reliably
indicates device saturation and thus it's safe to override user specified
vrate_min. However, this sometimes leads to unnecessary throttling,
especially on really fast devices, because vrate adjustments have delays and
inertia. It also confuses users because the behavior violates the explicitly
specified configuration.
This patch drops the special case handling so that vrate_min is always
applied.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/YIIo1HuyNmhDeiNx@slm.duckdns.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When initializing iocost for a queue, its rqos should be registered before
the blkcg policy is activated to allow policy data initiailization to lookup
the associated ioc. This unfortunately means that the rqos methods can be
called on bios before iocgs are attached to all existing blkgs.
While the race is theoretically possible on ioc_rqos_throttle(), it mostly
happened in ioc_rqos_merge() due to the difference in how they lookup ioc.
The former determines it from the passed in @rqos and then bails before
dereferencing iocg if the looked up ioc is disabled, which most likely is
the case if initialization is still in progress. The latter looked up ioc by
dereferencing the possibly NULL iocg making it a lot more prone to actually
triggering the bug.
* Make ioc_rqos_merge() use the same method as ioc_rqos_throttle() to look
up ioc for consistency.
* Make ioc_rqos_throttle() and ioc_rqos_merge() test for NULL iocg before
dereferencing it.
* Explain the danger of NULL iocgs in blk_iocost_init().
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Jonathan Lemon <bsd@fb.com>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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It will be helpful to trace the iocg's whole state, including active and
idle state. And we can easily expand the original iocost_iocg_activate
trace event to support a state trace class, including active and idle
state tracing.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Factor out the base vrate change code into a separate function
to fimplify the ioc_timer_fn().
No functional change.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Factor out the iocgs' state check into a separate function to
simplify the ioc_timer_fn().
No functional change.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We only use the hweight based usage ratio to calculate the new
hweight_inuse of the iocg to decide if this iocg can donate some
surplus vtime.
Thus move the usage ratio calculation to the correct place to
avoid unnecessary calculation for some vtime shortage iocgs.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Remove unnecessary advance declaration of struct ioc_gq.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Fix some typos in comments.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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To simplify block device lookup and a few other upcoming areas, make sure
that we always have a struct block_device available for each disk and
each partition, and only find existing block devices in bdget. The only
downside of this is that each device and partition uses a little more
memory. The upside will be that a lot of code can be simplified.
With that all we need to look up the block device is to lookup the inode
and do a few sanity checks on the gendisk, instead of the separate lookup
for the gendisk. For blk-cgroup which wants to access a gendisk without
opening it, a new blkdev_{get,put}_no_open low-level interface is added
to replace the previous get_gendisk use.
Note that the change to look up block device directly instead of the two
step lookup using struct gendisk causes a subtile change in behavior:
accessing a non-existing partition on an existing block device can now
cause a call to request_module. That call is harmless, and in practice
no recent system will access these nodes as they aren't created by udev
and static /dev/ setups are unusual.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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We have defined common interface blk_queue_registered() to
test QUEUE_FLAG_REGISTERED. Just use it.
Signed-off-by: Yufen Yu <yuyufen@huawei.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Remove redundant 'return' statement for 'void' functions.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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An iocg may have 0 debt but non-zero delay. The current debt forgiveness
logic doesn't act on such iocgs. This can lead to unexpected behaviors - an
iocg with a little bit of debt will have its delay canceled through debt
forgiveness but one w/o any debt but active delay will have to wait out
until its delay decays out.
This patch updates the debt handling logic so that it treats delays the same
as debts. If either debt or delay is active, debt forgiveness logic kicks in
and acts on both the same way.
Also, avoid turning the debt and delay directly to zero as that can confuse
state transitions.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Debt forgiveness logic was counting the number of consecutive !busy periods
as the trigger condition. While this usually works, it can easily be thrown
off by temporary fluctuations especially on configurations w/ short periods.
This patch reimplements debt forgiveness so that:
* Use the average usage over the forgiveness period instead of counting
consecutive periods.
* Debt is reduced at around the target rate (1/2 every 100ms) regardless of
ioc period duration.
* Usage threshold is raised to 50%. Combined with the preceding changes and
the switch to average usage, this makes debt forgivness a lot more
effective at reducing the amount of unnecessary idleness.
* Constants are renamed with DFGV_ prefix.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Debt sets the initial delay duration which is decayed over time. The current
debt reduction halved the debt but didn't change the delay. It prevented
future debts from increasing delay but didn't do anything to lower the
existing delay, limiting the mechanism's ability to reduce unnecessary
idling.
Reset iocg->delay to 0 after debt reduction so that iocg_kick_waitq()
recalculates new delay value based on the reduced debt amount.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Debt reduction was blocked if any iocg was short on budget in the past
period to avoid reducing debts while some iocgs are saturated. However, this
ends up unnecessarily blocking debt reduction due to temporary local
imbalances when the device is generally being underutilized, while also
failing to block when the underlying device is overwhelmed and the usage
becomes low from high latency.
Given that debt accumulation mostly happens with swapout bursts which can
significantly deteriorate the underlying device's latency response, the
current logic is not great.
Let's replace it with ioc->busy_level based condition so that we block debt
reduction when the underlying device is being saturated. ioc_forgive_debts()
call is moved after busy_level determination.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Debt reduction logic is going to be improved and expanded. Factor it out
into ioc_forgive_debts() and generalize the comment a bit. No functional
change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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adjust_inuse_and_calc_cost() is responsible for reducing the amount of
donated weights dynamically in period as the budget runs low. Because we
don't want to do full donation calculation in period, we keep latching up
inuse by INUSE_ADJ_STEP_PCT of the active weight of the cgroup until the
resulting hweight_inuse is satisfactory.
Unfortunately, the adj_step calculation was reading the active weight before
acquiring ioc->lock. Because the current thread could have lost race to
activate the iocg to another thread before entering this function, it may
read the active weight as zero before acquiring ioc->lock. When this
happens, the adj_step is calculated as zero and the incremental adjustment
loop becomes an infinite one.
Fix it by fetching the active weight after acquiring ioc->lock.
Fixes: b0853ab4a238 ("blk-iocost: revamp in-period donation snapbacks")
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Conceptually, root_iocg->hweight_donating must be less than WEIGHT_ONE but
all hweight calculations round up and thus it may end up >= WEIGHT_ONE
triggering divide-by-zero and other issues. Bound the value to avoid
surprises.
Fixes: e08d02aa5fc9 ("blk-iocost: implement Andy's method for donation weight updates")
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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These are really cheap to collect and can be useful in debugging iocost
behavior. Add them as debug stats for now.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Update and restore the inuse update tracepoints.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When an iocg accumulates too much vtime or gets deactivated, we throw away
some vtime, which lowers the overall device utilization. As the exact amount
which is being thrown away is known, we can compensate by accelerating the
vrate accordingly so that the extra vtime generated in the current period
matches what got lost.
This significantly improves work conservation when involving high weight
cgroups with intermittent and bursty IO patterns.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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A low weight iocg can amass a large amount of debt, for example, when
anonymous memory gets reclaimed aggressively. If the system has a lot of
memory paired with a slow IO device, the debt can span multiple seconds or
more. If there are no other subsequent IO issuers, the in-debt iocg may end
up blocked paying its debt while the IO device is idle.
This patch implements a mechanism to protect against such pathological
cases. If the device has been sufficiently idle for a substantial amount of
time, the debts are halved. The criteria are on the conservative side as we
want to resolve the rare extreme cases without impacting regular operation
by forgiving debts too readily.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Curently, iocost syncs the delay duration to the outstanding debt amount,
which seemed enough to protect the system from anon memory hogs. However,
that was mostly because the delay calcuation was using hweight_inuse which
quickly converges towards zero under debt for delay duration calculation,
often pusnishing debtors overly harshly for longer than deserved.
The previous patch fixed the delay calcuation and now the protection against
anonymous memory hogs isn't enough because the effect of delay is indirect
and non-linear and a huge amount of future debt can accumulate abruptly
while unthrottled.
This patch implements delay hysteresis so that delay is decayed
exponentially over time instead of getting cleared immediately as debt is
paid off. While the overall behavior is similar to the blk-cgroup
implementation used by blk-iolatency, a lot of the details are different and
due to the empirical nature of the mechanism, it's challenging to adapt the
mechanism for one controller without negatively impacting the other.
As the delay is gradually decayed now, there's no point in running it from
its own hrtimer. Periodic updates are now performed from ioc_timer_fn() and
the dedicated hrtimer is removed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Debt handling had several issues.
* How much inuse a debtor carries wasn't clearly defined. inuse would be
driven down over time from not issuing IOs but it'd be better to clamp it
to minimum immediately once in debt.
* How much can be paid off was determined by hweight_inuse. As inuse was
driven down, the payment amount would fall together regardless of the
debtor's active weight. This means that the debtors were punished harshly.
* ioc_rqos_merge() wasn't calling blkcg_schedule_throttle() after
iocg_kick_delay().
This patch revamps debt handling so that
* Debt handling owns inuse for iocgs in debt and keeps them at zero.
* Payment amount is determined by hweight_active. This is more deterministic
and safer than hweight_inuse but still far from ideal in that it doesn't
factor in possible donations from other iocgs for debt payments. This
likely needs further improvements in the future.
* iocg_rqos_merge() now calls blkcg_schedule_throttle() as necessary.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Andy Newell <newella@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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When the margin drops below the minimum on a donating iocg, donation is
immediately canceled in full. There are a couple shortcomings with the
current behavior.
* It's abrupt. A small temporary budget deficit can lead to a wide swing in
weight allocation and a large surplus.
* It's open coded in the issue path but not implemented for the merge path.
A series of merges at a low inuse can make the iocg incur debts and stall
incorrectly.
This patch reimplements in-period donation snapbacks so that
* inuse adjustment and cost calculations are factored into
adjust_inuse_and_calc_cost() which is called from both the issue and merge
paths.
* Snapbacks are more gradual. It occurs in quarter steps.
* A snapback triggers if the margin goes below the low threshold and is
lower than the budget at the time of the last adjustment.
* For the above, __propagate_weights() stores the margin in
iocg->saved_margin. Move iocg->last_inuse storing together into
__propagate_weights() for consistency.
* Full snapback is guaranteed when there are waiters.
* With precise donation and gradual snapbacks, inuse adjustments are now a
lot more effective and the value of scaling inuse on weight changes isn't
clear. Removed inuse scaling from weight_update().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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