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2022-09-23iocost_monitor: reorder BlkgIteratorElijah Conners1-5/+5
In order to comply with PEP 8, the first parameter of a class should be __init__. Signed-off-by: Elijah Conners <business@elijahpepe.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2020-09-01blk-iocost: update iocost_monitor.pyTejun Heo1-35/+19
iocost went through significant internal changes. Update iocost_monitor.py accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-07-30iocost_monitor: start from the oldest usage indexChengming Zhou1-1/+1
iocg usage_idx is the latest usage index, we should start from the oldest usage index to show the consecutive NR_USAGE_SLOTS usages. Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-09Merge branch 'block-5.7' into for-5.8/blockJens Axboe1-1/+6
Pull in block-5.7 fixes for 5.8. Mostly to resolve a conflict with the blk-iocost changes, but we also need the base of the bdi use-after-free as well as we build on top of it. * block-5.7: nvme: fix possible hang when ns scanning fails during error recovery nvme-pci: fix "slimmer CQ head update" bdi: add a ->dev_name field to struct backing_dev_info bdi: use bdi_dev_name() to get device name bdi: move bdi_dev_name out of line vboxsf: don't use the source name in the bdi name iocost: protect iocg->abs_vdebt with iocg->waitq.lock block: remove the bd_openers checks in blk_drop_partitions nvme: prevent double free in nvme_alloc_ns() error handling null_blk: Cleanup zoned device initialization null_blk: Fix zoned command handling block: remove unused header blk-iocost: Fix error on iocost_ioc_vrate_adj bdev: Reduce time holding bd_mutex in sync in blkdev_close() buffer: remove useless comment and WB_REASON_FREE_MORE_MEM, reason. Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-05iocost: protect iocg->abs_vdebt with iocg->waitq.lockTejun Heo1-1/+6
abs_vdebt is an atomic_64 which tracks how much over budget a given cgroup is and controls the activation of use_delay mechanism. Once a cgroup goes over budget from forced IOs, it has to pay it back with its future budget. The progress guarantee on debt paying comes from the iocg being active - active iocgs are processed by the periodic timer, which ensures that as time passes the debts dissipate and the iocg returns to normal operation. However, both iocg activation and vdebt handling are asynchronous and a sequence like the following may happen. 1. The iocg is in the process of being deactivated by the periodic timer. 2. A bio enters ioc_rqos_throttle(), calls iocg_activate() which returns without anything because it still sees that the iocg is already active. 3. The iocg is deactivated. 4. The bio from #2 is over budget but needs to be forced. It increases abs_vdebt and goes over the threshold and enables use_delay. 5. IO control is enabled for the iocg's subtree and now IOs are attributed to the descendant cgroups and the iocg itself no longer issues IOs. This leaves the iocg with stuck abs_vdebt - it has debt but inactive and no further IOs which can activate it. This can end up unduly punishing all the descendants cgroups. The usual throttling path has the same issue - the iocg must be active while throttled to ensure that future event will wake it up - and solves the problem by synchronizing the throttling path with a spinlock. abs_vdebt handling is another form of overage handling and shares a lot of characteristics including the fact that it isn't in the hottest path. This patch fixes the above and other possible races by strictly synchronizing abs_vdebt and use_delay handling with iocg->waitq.lock. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Vlad Dmitriev <vvd@fb.com> Cc: stable@vger.kernel.org # v5.4+ Fixes: e1518f63f246 ("blk-iocost: Don't let merges push vtime into the future") Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-30iocost_monitor: drop string wrap around numbers when outputting jsonTejun Heo1-21/+21
Wrapping numbers in strings is used by some to work around bit-width issues in some enviroments. The problem isn't innate to json and the workaround seems to cause more integration problems than help. Let's drop the string wrapping. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-30iocost_monitor: exit successfully if interval is zeroTejun Heo1-1/+5
This is to help external tools to decide whether iocost_monitor has all its requirements met or not based on the exit status of an -i0 run. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-17iocost: Fix iocost_monitor.py due to helper type mismatchTejun Heo1-2/+2
iocost_monitor.py broke with recent versions of drgn due to helper being stricter about types. Fix it so that it uses the correct type. Signed-off-by: Tejun Heo <tj@kernel.org> Suggested-by: Omar Sandoval <osandov@fb.com>
2019-09-10iocost_monitor: Report debtTejun Heo1-1/+4
Report debt and rename del_ms row to delay for consistency. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-10iocost_monitor: Report more info with higher accuracyTejun Heo1-7/+11
When outputting json: * Don't truncate numbers. * Report address of iocg to ease drilling down further. When outputting table: * Use math.ceil() for delay_ms so that small delays don't read as 0. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-09-10iocost_monitor: Always use strings for json valuesTejun Heo1-20/+20
Json has limited accuracy for numbers and can silently truncate 64bit values, which can be extremely confusing. Let's consistently use string encapsulated values for json output. While at it, convert an unnecesary f-string to str(). Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-08-28blkcg: add tools/cgroup/iocost_monitor.pyTejun Heo1-0/+270
Instead of mucking with debugfs and ->pd_stat(), add drgn based monitoring script. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>