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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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8c772a9bfc
Our test reported the following stack, and vmcore showed that ->inflight counter is -1. [ffffc9003fcc38d0] __schedule at ffffffff8173d95d [ffffc9003fcc3958] schedule at ffffffff8173de26 [ffffc9003fcc3970] io_schedule at ffffffff810bb6b6 [ffffc9003fcc3988] blkcg_iolatency_throttle at ffffffff813911cb [ffffc9003fcc3a20] rq_qos_throttle at ffffffff813847f3 [ffffc9003fcc3a48] blk_mq_make_request at ffffffff8137468a [ffffc9003fcc3b08] generic_make_request at ffffffff81368b49 [ffffc9003fcc3b68] submit_bio at ffffffff81368d7d [ffffc9003fcc3bb8] ext4_io_submit at ffffffffa031be00 [ext4] [ffffc9003fcc3c00] ext4_writepages at ffffffffa03163de [ext4] [ffffc9003fcc3d68] do_writepages at ffffffff811c49ae [ffffc9003fcc3d78] __filemap_fdatawrite_range at ffffffff811b6188 [ffffc9003fcc3e30] filemap_write_and_wait_range at ffffffff811b6301 [ffffc9003fcc3e60] ext4_sync_file at ffffffffa030cee8 [ext4] [ffffc9003fcc3ea8] vfs_fsync_range at ffffffff8128594b [ffffc9003fcc3ee8] do_fsync at ffffffff81285abd [ffffc9003fcc3f18] sys_fsync at ffffffff81285d50 [ffffc9003fcc3f28] do_syscall_64 at ffffffff81003c04 [ffffc9003fcc3f50] entry_SYSCALL_64_after_swapgs at ffffffff81742b8e The ->inflight counter may be negative (-1) if 1) blk-iolatency was disabled when the IO was issued, 2) blk-iolatency was enabled before this IO reached its endio, 3) the ->inflight counter is decreased from 0 to -1 in endio() In fact the hang can be easily reproduced by the below script, H=/sys/fs/cgroup/unified/ P=/sys/fs/cgroup/unified/test echo "+io" > $H/cgroup.subtree_control mkdir -p $P echo $$ > $P/cgroup.procs xfs_io -f -d -c "pwrite 0 4k" /dev/sdg echo "`cat /sys/block/sdg/dev` target=1000000" > $P/io.latency xfs_io -f -d -c "pwrite 0 4k" /dev/sdg This fixes the problem by freezing the queue so that while enabling/disabling iolatency, there is no inflight rq running. Note that quiesce_queue is not needed as this only updating iolatency configuration about which dispatching request_queue doesn't care. Signed-off-by: Liu Bo <bo.liu@linux.alibaba.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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.. | ||
partitions | ||
badblocks.c | ||
bfq-cgroup.c | ||
bfq-iosched.c | ||
bfq-iosched.h | ||
bfq-wf2q.c | ||
bio-integrity.c | ||
bio.c | ||
blk-cgroup.c | ||
blk-core.c | ||
blk-exec.c | ||
blk-flush.c | ||
blk-integrity.c | ||
blk-ioc.c | ||
blk-iolatency.c | ||
blk-lib.c | ||
blk-map.c | ||
blk-merge.c | ||
blk-mq-cpumap.c | ||
blk-mq-debugfs-zoned.c | ||
blk-mq-debugfs.c | ||
blk-mq-debugfs.h | ||
blk-mq-pci.c | ||
blk-mq-rdma.c | ||
blk-mq-sched.c | ||
blk-mq-sched.h | ||
blk-mq-sysfs.c | ||
blk-mq-tag.c | ||
blk-mq-tag.h | ||
blk-mq-virtio.c | ||
blk-mq.c | ||
blk-mq.h | ||
blk-pm.c | ||
blk-pm.h | ||
blk-rq-qos.c | ||
blk-rq-qos.h | ||
blk-settings.c | ||
blk-softirq.c | ||
blk-stat.c | ||
blk-stat.h | ||
blk-sysfs.c | ||
blk-throttle.c | ||
blk-timeout.c | ||
blk-wbt.c | ||
blk-wbt.h | ||
blk-zoned.c | ||
blk.h | ||
bounce.c | ||
bsg-lib.c | ||
bsg.c | ||
cmdline-parser.c | ||
compat_ioctl.c | ||
elevator.c | ||
genhd.c | ||
ioctl.c | ||
ioprio.c | ||
Kconfig | ||
Kconfig.iosched | ||
kyber-iosched.c | ||
Makefile | ||
mq-deadline.c | ||
opal_proto.h | ||
partition-generic.c | ||
scsi_ioctl.c | ||
sed-opal.c | ||
t10-pi.c |