• Ming Lei's avatar
    block: deactivate blk_stat timer in wbt_disable_default() · 544fbd16
    Ming Lei authored
    rwb_enabled() can't be changed when there is any inflight IO.
    
    wbt_disable_default() may set rwb->wb_normal as zero, however the
    blk_stat timer may still be pending, and the timer function will update
    wrb->wb_normal again.
    
    This patch introduces blk_stat_deactivate() and applies it in
    wbt_disable_default(), then the following IO hang triggered when running
    parted & switching io scheduler can be fixed:
    
    [  369.937806] INFO: task parted:3645 blocked for more than 120 seconds.
    [  369.938941]       Not tainted 4.20.0-rc6-00284-g906c801e5248 #498
    [  369.939797] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
    [  369.940768] parted          D    0  3645   3239 0x00000000
    [  369.941500] Call Trace:
    [  369.941874]  ? __schedule+0x6d9/0x74c
    [  369.942392]  ? wbt_done+0x5e/0x5e
    [  369.942864]  ? wbt_cleanup_cb+0x16/0x16
    [  369.943404]  ? wbt_done+0x5e/0x5e
    [  369.943874]  schedule+0x67/0x78
    [  369.944298]  io_schedule+0x12/0x33
    [  369.944771]  rq_qos_wait+0xb5/0x119
    [  369.945193]  ? karma_partition+0x1c2/0x1c2
    [  369.945691]  ? wbt_cleanup_cb+0x16/0x16
    [  369.946151]  wbt_wait+0x85/0xb6
    [  369.946540]  __rq_qos_throttle+0x23/0x2f
    [  369.947014]  blk_mq_make_request+0xe6/0x40a
    [  369.947518]  generic_make_request+0x192/0x2fe
    [  369.948042]  ? submit_bio+0x103/0x11f
    [  369.948486]  ? __radix_tree_lookup+0x35/0xb5
    [  369.949011]  submit_bio+0x103/0x11f
    [  369.949436]  ? blkg_lookup_slowpath+0x25/0x44
    [  369.949962]  submit_bio_wait+0x53/0x7f
    [  369.950469]  blkdev_issue_flush+0x8a/0xae
    [  369.951032]  blkdev_fsync+0x2f/0x3a
    [  369.951502]  do_fsync+0x2e/0x47
    [  369.951887]  __x64_sys_fsync+0x10/0x13
    [  369.952374]  do_syscall_64+0x89/0x149
    [  369.952819]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [  369.953492] RIP: 0033:0x7f95a1e729d4
    [  369.953996] Code: Bad RIP value.
    [  369.954456] RSP: 002b:00007ffdb570dd48 EFLAGS: 00000246 ORIG_RAX: 000000000000004a
    [  369.955506] RAX: ffffffffffffffda RBX: 000055c2139c6be0 RCX: 00007f95a1e729d4
    [  369.956389] RDX: 0000000000000001 RSI: 0000000000001261 RDI: 0000000000000004
    [  369.957325] RBP: 0000000000000002 R08: 0000000000000000 R09: 000055c2139c6ce0
    [  369.958199] R10: 0000000000000000 R11: 0000000000000246 R12: 000055c2139c0380
    [  369.959143] R13: 0000000000000004 R14: 0000000000000100 R15: 0000000000000008
    
    Cc: stable@vger.kernel.org
    Cc: Paolo Valente <paolo.valente@linaro.org>
    Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
    Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
    544fbd16
blk-wbt.c 17.9 KB