1. 18 Dec, 2018 16 commits
    • Eric Biggers's avatar
      dm verity: log the hash algorithm implementation · bbf6a566
      Eric Biggers authored
      Log the hash algorithm's driver name when a dm-verity target is created.
      This will help people determine whether the expected implementation is
      being used.  It can make an enormous difference; e.g., SHA-256 on ARM
      can be 8x faster with the crypto extensions than without.  It can also
      be useful to know if an implementation using an external crypto
      accelerator is being used instead of a software implementation.
      
      Example message:
      
      [   35.281945] device-mapper: verity: sha256 using implementation "sha256-ce"
      
      We've already found the similar message in fs/crypto/keyinfo.c to be
      very useful.
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      bbf6a566
    • Eric Biggers's avatar
      dm crypt: log the encryption algorithm implementation · af331eba
      Eric Biggers authored
      Log the encryption algorithm's driver name when a dm-crypt target is
      created.  This will help people determine whether the expected
      implementation is being used.  In some cases we've seen people do
      benchmarks and reject using encryption for performance reasons, when in
      fact they used a much slower implementation than was possible on the
      hardware.  It can make an enormous difference; e.g., AES-XTS on ARM can
      be over 10x faster with the crypto extensions than without.  It can also
      be useful to know if an implementation using an external crypto
      accelerator is being used instead of a software implementation.
      
      Example message:
      
      [   29.307629] device-mapper: crypt: xts(aes) using implementation "xts-aes-ce"
      
      We've already found the similar message in fs/crypto/keyinfo.c to be
      very useful.
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      af331eba
    • Colin Ian King's avatar
      dm integrity: fix spelling mistake in workqueue name · e8c2566f
      Colin Ian King authored
      Rename the workqueue from dm-intergrity-recalc to dm-integrity-recalc.
      Signed-off-by: default avatarColin Ian King <colin.king@canonical.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      e8c2566f
    • Sweet Tea's avatar
      dm flakey: Properly corrupt multi-page bios. · a00f5276
      Sweet Tea authored
      The flakey target is documented to be able to corrupt the Nth byte in
      a bio, but does not corrupt byte indices after the first biovec in the
      bio. Change the corrupting function to actually corrupt the Nth byte
      no matter in which biovec that index falls.
      
      A test device generating two-page bios, atop a flakey device configured
      to corrupt a byte index on the second page, verified both the failure
      to corrupt before this patch and the expected corruption after this
      change.
      Signed-off-by: default avatarJohn Dorminy <jdorminy@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      a00f5276
    • Milan Broz's avatar
      dm: Check for device sector overflow if CONFIG_LBDAF is not set · ef87bfc2
      Milan Broz authored
      Reference to a device in device-mapper table contains offset in sectors.
      
      If the sector_t is 32bit integer (CONFIG_LBDAF is not set), then
      several device-mapper targets can overflow this offset and validity
      check is then performed on a wrong offset and a wrong table is activated.
      
      See for example (on 32bit without CONFIG_LBDAF) this overflow:
      
        # dmsetup create test --table "0 2048 linear /dev/sdg 4294967297"
        # dmsetup table test
        0 2048 linear 8:96 1
      
      This patch adds explicit check for overflow if the offset is sector_t type.
      Signed-off-by: default avatarMilan Broz <gmazyland@gmail.com>
      Reviewed-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      ef87bfc2
    • AliOS system security's avatar
      dm crypt: use u64 instead of sector_t to store iv_offset · 8d683dcd
      AliOS system security authored
      The iv_offset in the mapping table of crypt target is a 64bit number when
      IV algorithm is plain64, plain64be, essiv or benbi. It will be assigned to
      iv_offset of struct crypt_config, cc_sector of struct convert_context and
      iv_sector of struct dm_crypt_request. These structures members are defined
      as a sector_t. But sector_t is 32bit when CONFIG_LBDAF is not set in 32bit
      kernel. In this situation sector_t is not big enough to store the 64bit
      iv_offset.
      
      Here is a reproducer.
      Prepare test image and device (loop is automatically allocated by cryptsetup):
      
        # dd if=/dev/zero of=tst.img bs=1M count=1
        # echo "tst"|cryptsetup open --type plain -c aes-xts-plain64 \
        --skip 500000000000000000 tst.img test
      
      On 32bit system (use IV offset value that overflows to 64bit; CONFIG_LBDAF if off)
      and device checksum is wrong:
      
        # dmsetup table test --showkeys
        0 2048 crypt aes-xts-plain64 dfa7cfe3c481f2239155739c42e539ae8f2d38f304dcc89d20b26f69daaf0933 3551657984 7:0 0
      
        # sha256sum /dev/mapper/test
        533e25c09176632b3794f35303488c4a8f3f965dffffa6ec2df347c168cb6c19 /dev/mapper/test
      
      On 64bit system (and on 32bit system with the patch), table and checksum is now correct:
      
        # dmsetup table test --showkeys
        0 2048 crypt aes-xts-plain64 dfa7cfe3c481f2239155739c42e539ae8f2d38f304dcc89d20b26f69daaf0933 500000000000000000 7:0 0
      
        # sha256sum /dev/mapper/test
        5d16160f9d5f8c33d8051e65fdb4f003cc31cd652b5abb08f03aa6fce0df75fc /dev/mapper/test
      Signed-off-by: default avatarAliOS system security <alios_sys_security@linux.alibaba.com>
      Tested-and-Reviewed-by: default avatarMilan Broz <gmazyland@gmail.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      8d683dcd
    • Nikos Tsironis's avatar
      dm kcopyd: Fix bug causing workqueue stalls · d7e6b8df
      Nikos Tsironis authored
      When using kcopyd to run callbacks through dm_kcopyd_do_callback() or
      submitting copy jobs with a source size of 0, the jobs are pushed
      directly to the complete_jobs list, which could be under processing by
      the kcopyd thread. As a result, the kcopyd thread can continue running
      completed jobs indefinitely, without releasing the CPU, as long as
      someone keeps submitting new completed jobs through the aforementioned
      paths. Processing of work items, queued for execution on the same CPU as
      the currently running kcopyd thread, is thus stalled for excessive
      amounts of time, hurting performance.
      
      Running the following test, from the device mapper test suite [1],
      
        dmtest run --suite snapshot -n parallel_io_to_many_snaps_N
      
      , with 8 active snapshots, we get, in dmesg, messages like the
      following:
      
      [68899.948523] BUG: workqueue lockup - pool cpus=0 node=0 flags=0x0 nice=0 stuck for 95s!
      [68899.949282] Showing busy workqueues and worker pools:
      [68899.949288] workqueue events: flags=0x0
      [68899.949295]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
      [68899.949306]     pending: vmstat_shepherd, cache_reap
      [68899.949331] workqueue mm_percpu_wq: flags=0x8
      [68899.949337]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
      [68899.949345]     pending: vmstat_update
      [68899.949387] workqueue dm_bufio_cache: flags=0x8
      [68899.949392]   pwq 4: cpus=2 node=0 flags=0x0 nice=0 active=1/256
      [68899.949400]     pending: work_fn [dm_bufio]
      [68899.949423] workqueue kcopyd: flags=0x8
      [68899.949429]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
      [68899.949437]     pending: do_work [dm_mod]
      [68899.949452] workqueue kcopyd: flags=0x8
      [68899.949458]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
      [68899.949466]     in-flight: 13:do_work [dm_mod]
      [68899.949474]     pending: do_work [dm_mod]
      [68899.949487] workqueue kcopyd: flags=0x8
      [68899.949493]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
      [68899.949501]     pending: do_work [dm_mod]
      [68899.949515] workqueue kcopyd: flags=0x8
      [68899.949521]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
      [68899.949529]     pending: do_work [dm_mod]
      [68899.949541] workqueue kcopyd: flags=0x8
      [68899.949547]   pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
      [68899.949555]     pending: do_work [dm_mod]
      [68899.949568] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=95s workers=4 idle: 27130 27223 1084
      
      Fix this by splitting the complete_jobs list into two parts: A user
      facing part, named callback_jobs, and one used internally by kcopyd,
      retaining the name complete_jobs. dm_kcopyd_do_callback() and
      dispatch_job() now push their jobs to the callback_jobs list, which is
      spliced to the complete_jobs list once, every time the kcopyd thread
      wakes up. This prevents kcopyd from hogging the CPU indefinitely and
      causing workqueue stalls.
      
      Re-running the aforementioned test:
      
        * Workqueue stalls are eliminated
        * The maximum writing time among all targets is reduced from 09m37.10s
          to 06m04.85s and the total run time of the test is reduced from
          10m43.591s to 7m19.199s
      
      [1] https://github.com/jthornber/device-mapper-test-suiteSigned-off-by: default avatarNikos Tsironis <ntsironis@arrikto.com>
      Signed-off-by: default avatarIlias Tsitsimpis <iliastsi@arrikto.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      d7e6b8df
    • Nikos Tsironis's avatar
      dm snapshot: Fix excessive memory usage and workqueue stalls · 721b1d98
      Nikos Tsironis authored
      kcopyd has no upper limit to the number of jobs one can allocate and
      issue. Under certain workloads this can lead to excessive memory usage
      and workqueue stalls. For example, when creating multiple dm-snapshot
      targets with a 4K chunk size and then writing to the origin through the
      page cache. Syncing the page cache causes a large number of BIOs to be
      issued to the dm-snapshot origin target, which itself issues an even
      larger (because of the BIO splitting taking place) number of kcopyd
      jobs.
      
      Running the following test, from the device mapper test suite [1],
      
        dmtest run --suite snapshot -n many_snapshots_of_same_volume_N
      
      , with 8 active snapshots, results in the kcopyd job slab cache growing
      to 10G. Depending on the available system RAM this can lead to the OOM
      killer killing user processes:
      
      [463.492878] kthreadd invoked oom-killer: gfp_mask=0x6040c0(GFP_KERNEL|__GFP_COMP),
                    nodemask=(null), order=1, oom_score_adj=0
      [463.492894] kthreadd cpuset=/ mems_allowed=0
      [463.492948] CPU: 7 PID: 2 Comm: kthreadd Not tainted 4.19.0-rc7 #3
      [463.492950] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
      [463.492952] Call Trace:
      [463.492964]  dump_stack+0x7d/0xbb
      [463.492973]  dump_header+0x6b/0x2fc
      [463.492987]  ? lockdep_hardirqs_on+0xee/0x190
      [463.493012]  oom_kill_process+0x302/0x370
      [463.493021]  out_of_memory+0x113/0x560
      [463.493030]  __alloc_pages_slowpath+0xf40/0x1020
      [463.493055]  __alloc_pages_nodemask+0x348/0x3c0
      [463.493067]  cache_grow_begin+0x81/0x8b0
      [463.493072]  ? cache_grow_begin+0x874/0x8b0
      [463.493078]  fallback_alloc+0x1e4/0x280
      [463.493092]  kmem_cache_alloc_node+0xd6/0x370
      [463.493098]  ? copy_process.part.31+0x1c5/0x20d0
      [463.493105]  copy_process.part.31+0x1c5/0x20d0
      [463.493115]  ? __lock_acquire+0x3cc/0x1550
      [463.493121]  ? __switch_to_asm+0x34/0x70
      [463.493129]  ? kthread_create_worker_on_cpu+0x70/0x70
      [463.493135]  ? finish_task_switch+0x90/0x280
      [463.493165]  _do_fork+0xe0/0x6d0
      [463.493191]  ? kthreadd+0x19f/0x220
      [463.493233]  kernel_thread+0x25/0x30
      [463.493235]  kthreadd+0x1bf/0x220
      [463.493242]  ? kthread_create_on_cpu+0x90/0x90
      [463.493248]  ret_from_fork+0x3a/0x50
      [463.493279] Mem-Info:
      [463.493285] active_anon:20631 inactive_anon:4831 isolated_anon:0
      [463.493285]  active_file:80216 inactive_file:80107 isolated_file:435
      [463.493285]  unevictable:0 dirty:51266 writeback:109372 unstable:0
      [463.493285]  slab_reclaimable:31191 slab_unreclaimable:3483521
      [463.493285]  mapped:526 shmem:4903 pagetables:1759 bounce:0
      [463.493285]  free:33623 free_pcp:2392 free_cma:0
      ...
      [463.493489] Unreclaimable slab info:
      [463.493513] Name                      Used          Total
      [463.493522] bio-6                   1028KB       1028KB
      [463.493525] bio-5                   1028KB       1028KB
      [463.493528] dm_snap_pending_exception     236783KB     243789KB
      [463.493531] dm_exception              41KB         42KB
      [463.493534] bio-4                   1216KB       1216KB
      [463.493537] bio-3                 439396KB     439396KB
      [463.493539] kcopyd_job           6973427KB    6973427KB
      ...
      [463.494340] Out of memory: Kill process 1298 (ruby2.3) score 1 or sacrifice child
      [463.494673] Killed process 1298 (ruby2.3) total-vm:435740kB, anon-rss:20180kB, file-rss:4kB, shmem-rss:0kB
      [463.506437] oom_reaper: reaped process 1298 (ruby2.3), now anon-rss:0kB, file-rss:0kB, shmem-rss:0kB
      
      Moreover, issuing a large number of kcopyd jobs results in kcopyd
      hogging the CPU, while processing them. As a result, processing of work
      items, queued for execution on the same CPU as the currently running
      kcopyd thread, is stalled for long periods of time, hurting performance.
      Running the aforementioned test we get, in dmesg, messages like the
      following:
      
      [67501.194592] BUG: workqueue lockup - pool cpus=4 node=0 flags=0x0 nice=0 stuck for 27s!
      [67501.195586] Showing busy workqueues and worker pools:
      [67501.195591] workqueue events: flags=0x0
      [67501.195597]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
      [67501.195611]     pending: cache_reap
      [67501.195641] workqueue mm_percpu_wq: flags=0x8
      [67501.195645]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
      [67501.195656]     pending: vmstat_update
      [67501.195682] workqueue kblockd: flags=0x18
      [67501.195687]   pwq 5: cpus=2 node=0 flags=0x0 nice=-20 active=1/256
      [67501.195698]     pending: blk_timeout_work
      [67501.195753] workqueue kcopyd: flags=0x8
      [67501.195757]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
      [67501.195768]     pending: do_work [dm_mod]
      [67501.195802] workqueue kcopyd: flags=0x8
      [67501.195806]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
      [67501.195817]     pending: do_work [dm_mod]
      [67501.195834] workqueue kcopyd: flags=0x8
      [67501.195838]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
      [67501.195848]     pending: do_work [dm_mod]
      [67501.195881] workqueue kcopyd: flags=0x8
      [67501.195885]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=1/256
      [67501.195896]     pending: do_work [dm_mod]
      [67501.195920] workqueue kcopyd: flags=0x8
      [67501.195924]   pwq 8: cpus=4 node=0 flags=0x0 nice=0 active=2/256
      [67501.195935]     in-flight: 67:do_work [dm_mod]
      [67501.195945]     pending: do_work [dm_mod]
      [67501.195961] pool 8: cpus=4 node=0 flags=0x0 nice=0 hung=27s workers=3 idle: 129 23765
      
      The root cause for these issues is the way dm-snapshot uses kcopyd. In
      particular, the lack of an explicit or implicit limit to the maximum
      number of in-flight COW jobs. The merging path is not affected because
      it implicitly limits the in-flight kcopyd jobs to one.
      
      Fix these issues by using a semaphore to limit the maximum number of
      in-flight kcopyd jobs. We grab the semaphore before allocating a new
      kcopyd job in start_copy() and start_full_bio() and release it after the
      job finishes in copy_callback().
      
      The initial semaphore value is configurable through a module parameter,
      to allow fine tuning the maximum number of in-flight COW jobs. Setting
      this parameter to zero initializes the semaphore to INT_MAX.
      
      A default value of 2048 maximum in-flight kcopyd jobs was chosen. This
      value was decided experimentally as a trade-off between memory
      consumption, stalling the kernel's workqueues and maintaining a high
      enough throughput.
      
      Re-running the aforementioned test:
      
        * Workqueue stalls are eliminated
        * kcopyd's job slab cache uses a maximum of 130MB
        * The time taken by the test to write to the snapshot-origin target is
          reduced from 05m20.48s to 03m26.38s
      
      [1] https://github.com/jthornber/device-mapper-test-suiteSigned-off-by: default avatarNikos Tsironis <ntsironis@arrikto.com>
      Signed-off-by: default avatarIlias Tsitsimpis <iliastsi@arrikto.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      721b1d98
    • Shenghui Wang's avatar
      dm bufio: update comment in dm-bufio.c · ef992373
      Shenghui Wang authored
      * Hashtable has been replaced by rbtree to manage buffers.
        Update the comment.
      * Fix typo in the comment for dm_bufio_issue_flush
      Signed-off-by: default avatarShenghui Wang <shhuiw@foxmail.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      ef992373
    • Shenghui Wang's avatar
      dm writecache: fix typo in error msg for creating writecache_flush_thread · e8ea141a
      Shenghui Wang authored
      The error msg should be "flush thread" instead of "endio thread"
      for writecache_flush_thread.
      Signed-off-by: default avatarShenghui Wang <shhuiw@foxmail.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      e8ea141a
    • Mike Snitzer's avatar
      dm: remove indirect calls from __send_changing_extent_only() · 53b47168
      Mike Snitzer authored
      No need to be so fancy.
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      53b47168
    • wuzhouhui's avatar
      dm mpath: only flush workqueue when needed · 935fcc56
      wuzhouhui authored
      The workqueues are shared by many multipath devices, only flush whole
      workqueue when necessary.  Otherwise, we just flush works as needed.
      Signed-off-by: default avatarwuzhouhui <wuzhouhui14@mails.ucas.ac.cn>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      935fcc56
    • Mike Snitzer's avatar
      2adc5c55
    • Mikulas Patocka's avatar
      dm: avoid indirect call in __dm_make_request · 24113d48
      Mikulas Patocka authored
      Indirect calls are inefficient because of retpolines that are used for
      spectre workaround. This patch replaces an indirect call with a condition
      (that can be predicted by the branch predictor).
      Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
      Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
      24113d48
    • Ming Lei's avatar
      blk-mq: enable IO poll if .nr_queues of type poll > 0 · cd19181b
      Ming Lei authored
      The queue mapping of type poll only exists when set->map[HCTX_TYPE_POLL].nr_queues
      is bigger than zero, so enhance the constraint by checking .nr_queues of type poll
      before enabling IO poll.
      
      Otherwise IO race & timeout can be observed when running block/007.
      
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      cd19181b
    • Jens Axboe's avatar
      blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight() · 3c94d83c
      Jens Axboe authored
      There's a single user of this function, dm, and dm just wants
      to check if IO is inflight, not that it's just allocated.
      
      This fixes a hang with srp/002 in blktests with dm, where it tries
      to suspend but waits for inflight IO to finish first. As it checks
      for just allocated requests, this fails.
      Tested-by: default avatarMike Snitzer <snitzer@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      3c94d83c
  2. 17 Dec, 2018 11 commits
    • Ming Lei's avatar
      blk-mq: skip zero-queue maps in blk_mq_map_swqueue · e5edd5f2
      Ming Lei authored
      From 7e849dd9 ("nvme-pci: don't share queue maps"), the mapping
      table won't be initialized actually if map->nr_queues is zero, so
      we can't use blk_mq_map_queue_type() to retrieve hctx any more.
      
      This way still may cause broken mapping, fix it by skipping zero-queues
      maps in blk_mq_map_swqueue().
      
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Mike Snitzer <snitzer@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      e5edd5f2
    • Dennis Zhou's avatar
      block: fix blk-iolatency accounting underflow · 13369816
      Dennis Zhou authored
      The blk-iolatency controller measures the time from rq_qos_throttle() to
      rq_qos_done_bio() and attributes this time to the first bio that needs
      to create the request. This means if a bio is plug-mergeable or
      bio-mergeable, it gets to bypass the blk-iolatency controller.
      
      The recent series [1], to tag all bios w/ blkgs undermined how iolatency
      was determining which bios it was charging and should process in
      rq_qos_done_bio(). Because all bios are being tagged, this caused the
      atomic_t for the struct rq_wait inflight count to underflow and result
      in a stall.
      
      This patch adds a new flag BIO_TRACKED to let controllers know that a
      bio is going through the rq_qos path. blk-iolatency now checks if this
      flag is set to see if it should process the bio in rq_qos_done_bio().
      
      Overloading BLK_QUEUE_ENTERED works, but makes the flag rules confusing.
      BIO_THROTTLED was another candidate, but the flag is set for all bios
      that have gone through blk-throttle code. Overloading a flag comes with
      the burden of making sure that when either implementation changes, a
      change in setting rules for one doesn't cause a bug in the other. So
      here, we unfortunately opt for adding a new flag.
      
      [1] https://lore.kernel.org/lkml/20181205171039.73066-1-dennis@kernel.org/
      
      Fixes: 5cdf2e3f ("blkcg: associate blkg when associating a device")
      Signed-off-by: default avatarDennis Zhou <dennis@kernel.org>
      Cc: Josef Bacik <josef@toxicpanda.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      13369816
    • Ming Lei's avatar
      blk-mq: fix dispatch from sw queue · c16d6b5a
      Ming Lei authored
      When a request is added to rq list of sw queue(ctx), the rq may be from
      a different type of hctx, especially after multi queue mapping is
      introduced.
      
      So when dispach request from sw queue via blk_mq_flush_busy_ctxs() or
      blk_mq_dequeue_from_ctx(), one request belonging to other queue type of
      hctx can be dispatched to current hctx in case that read queue or poll
      queue is enabled.
      
      This patch fixes this issue by introducing per-queue-type list.
      
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      
      Changed by me to not use separately cacheline aligned lists, just
      place them all in the same cacheline where we had just the one list
      and lock before.
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      c16d6b5a
    • Damien Le Moal's avatar
      block: mq-deadline: Fix write completion handling · 7211aef8
      Damien Le Moal authored
      For a zoned block device using mq-deadline, if a write request for a
      zone is received while another write was already dispatched for the same
      zone, dd_dispatch_request() will return NULL and the newly inserted
      write request is kept in the scheduler queue waiting for the ongoing
      zone write to complete. With this behavior, when no other request has
      been dispatched, rq_list in blk_mq_sched_dispatch_requests() is empty
      and blk_mq_sched_mark_restart_hctx() not called. This in turn leads to
      __blk_mq_free_request() call of blk_mq_sched_restart() to not run the
      queue when the already dispatched write request completes. The newly
      dispatched request stays stuck in the scheduler queue until eventually
      another request is submitted.
      
      This problem does not affect SCSI disk as the SCSI stack handles queue
      restart on request completion. However, this problem is can be triggered
      the nullblk driver with zoned mode enabled.
      
      Fix this by always requesting a queue restart in dd_dispatch_request()
      if no request was dispatched while WRITE requests are queued.
      
      Fixes: 5700f691 ("mq-deadline: Introduce zone locking support")
      Cc: <stable@vger.kernel.org>
      Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
      
      Add missing export of blk_mq_sched_restart()
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      7211aef8
    • Christoph Hellwig's avatar
      nvme-pci: don't share queue maps · 7e849dd9
      Christoph Hellwig authored
      Now that the block layer checks if a queue map has any queues inside
      it there is no more reason to duplicate the maps for the non-default
      types.
      Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      7e849dd9
    • Christoph Hellwig's avatar
      blk-mq: only dispatch to non-defauly queue maps if they have queues · 5aceaeb2
      Christoph Hellwig authored
      We should check if a given queue map actually has queues enabled before
      dispatching to it.  This allows drivers to not initialize optional but
      not used map types, which subsequently will allow fixing problems with
      queue map rebuilds for that case.
      Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      5aceaeb2
    • Ming Lei's avatar
      blk-mq: export hctx->type in debugfs instead of sysfs · 346fc108
      Ming Lei authored
      Now we only export hctx->type via sysfs, and there isn't such info
      in hctx entry under debugfs. We often use debugfs only to diagnose
      queue mapping issue, so add the support in debugfs.
      
      Queue mapping becomes a bit more complicated after multiple queue
      mapping is supported, we may write blktest to verify if queue mapping
      is valid based on blk-mq-debugfs.
      
      Given not necessary to export hctx->type twice, so remove the export
      from sysfs.
      
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Mike Snitzer <snitzer@redhat.com>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      346fc108
    • Ming Lei's avatar
      blk-mq: fix allocation for queue mapping table · 07b35eb5
      Ming Lei authored
      Type of each element in queue mapping table is 'unsigned int,
      intead of 'struct blk_mq_queue_map)', so fix it.
      
      Cc: Jeff Moyer <jmoyer@redhat.com>
      Cc: Mike Snitzer <snitzer@redhat.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      07b35eb5
    • Ming Lei's avatar
      blk-wbt: export internal state via debugfs · d19afebc
      Ming Lei authored
      This information is helpful to either investigate issues, or understand
      wbt's internal behaviour.
      
      Cc: Bart Van Assche <bart.vanassche@wdc.com>
      Cc: Omar Sandoval <osandov@fb.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Josef Bacik <josef@toxicpanda.com>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      d19afebc
    • Ming Lei's avatar
      blk-mq-debugfs: support rq_qos · cc56694f
      Ming Lei authored
      blk-mq-debugfs has been proved as very helpful for debug some
      tough issues, such as IO hang.
      
      We have seen blk-wbt related IO hang several times, even inside
      Red Hat BZ, there is such report not sovled yet, so this patch
      adds support debugfs on rq_qos.
      
      Cc: Bart Van Assche <bart.vanassche@wdc.com>
      Cc: Omar Sandoval <osandov@fb.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Cc: Josef Bacik <josef@toxicpanda.com>
      Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      cc56694f
    • Damien Le Moal's avatar
      block: update sysfs documentation · f9824952
      Damien Le Moal authored
      Add the description of the zoned, nr_zones and chunk_sectors sysfs queue
      attributes to Documentation/block/queue-sysfs.txt. The description of
      the zoned and chunk_sector attributes are mostly copied from
      ABI/testing/sysfs-block (added a typo fix). While at it, also fix a
      typo in the description of the io_poll_delay attribute.
      
      nr_zones description is also added to ABI/testing/sysfs-block and
      contact email address updated for the zoned attribute.
      Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      f9824952
  3. 16 Dec, 2018 8 commits
  4. 14 Dec, 2018 4 commits
  5. 13 Dec, 2018 1 commit