- 14 Mar, 2016 1 commit
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Bryn M. Reeves authored
An "old" (.request_fn) DM 'struct request' stores a pointer to the associated 'struct dm_rq_target_io' in rq->special. dm_requeue_original_request(), previously named dm_requeue_unmapped_original_request(), called dm_unprep_request() to reset rq->special to NULL. But rq_end_stats() would go on to hit a NULL pointer deference because its call to tio_from_request() returned NULL. Fix this by calling rq_end_stats() _before_ dm_unprep_request() Signed-off-by:
Bryn M. Reeves <bmr@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Fixes: e262f347 ("dm stats: add support for request-based DM devices") Cc: stable@vger.kernel.org # 4.2+
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- 11 Mar, 2016 1 commit
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Mike Snitzer authored
Commit 0a927c2f ("dm thin: return -ENOSPC when erroring retry list due to out of data space") was a step in the right direction but didn't go far enough. Add a new 'out_of_data_space' flag to 'struct pool' and set it if/when the pool runs of of data space. This fixes cell_error() and error_retry_list() to not blindly return -EIO. We cannot rely on the 'error_if_no_space' feature flag since it is transient (in that it can be reset once space is added, plus it only controls whether errors are issued, it doesn't reflect whether the pool is actually out of space). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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- 10 Mar, 2016 14 commits
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Joe Thornber authored
Otherwise operations may be attempted that will only ever go on to crash (since the metadata device is either missing or unreliable if 'fail_io' is set). Signed-off-by:
Joe Thornber <ejt@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Cc: stable@vger.kernel.org
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
clone_bio() now checks if bio_integrity_clone() returned an error rather than just drop it on the floor. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Joe Thornber authored
If a transaction abort has failed then we can no longer use the metadata device. Typically this happens if the superblock is unreadable. This fix addresses a crash seen during metadata device failure testing. Fixes: 8a01a6af ("dm thin: prefetch missing metadata pages") Cc: stable@vger.kernel.org # 3.19+ Signed-off-by:
Joe Thornber <ejt@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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DingXiang authored
Otherwise loading a "snapshot" table using the same device for the origin and COW devices, e.g.: echo "0 20971520 snapshot 253:3 253:3 P 8" | dmsetup create snap will trigger: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 [ 1958.979934] IP: [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot] [ 1958.989655] PGD 0 [ 1958.991903] Oops: 0000 [#1] SMP ... [ 1959.059647] CPU: 9 PID: 3556 Comm: dmsetup Tainted: G IO 4.5.0-rc5.snitm+ #150 ... [ 1959.083517] task: ffff8800b9660c80 ti: ffff88032a954000 task.ti: ffff88032a954000 [ 1959.091865] RIP: 0010:[<ffffffffa040efba>] [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot] [ 1959.104295] RSP: 0018:ffff88032a957b30 EFLAGS: 00010246 [ 1959.110219] RAX: 0000000000000000 RBX: 0000000000000008 RCX: 0000000000000001 [ 1959.118180] RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffff880329334a00 [ 1959.126141] RBP: ffff88032a957b50 R08: 0000000000000000 R09: 0000000000000001 [ 1959.134102] R10: 000000000000000a R11: f000000000000000 R12: ffff880330884d80 [ 1959.142061] R13: 0000000000000008 R14: ffffc90001c13088 R15: ffff880330884d80 [ 1959.150021] FS: 00007f8926ba3840(0000) GS:ffff880333440000(0000) knlGS:0000000000000000 [ 1959.159047] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1959.165456] CR2: 0000000000000098 CR3: 000000032f48b000 CR4: 00000000000006e0 [ 1959.173415] Stack: [ 1959.175656] ffffc90001c13040 ffff880329334a00 ffff880330884ed0 ffff88032a957bdc [ 1959.183946] ffff88032a957bb8 ffffffffa040f225 ffff880329334a30 ffff880300000000 [ 1959.192233] ffffffffa04133e0 ffff880329334b30 0000000830884d58 00000000569c58cf [ 1959.200521] Call Trace: [ 1959.203248] [<ffffffffa040f225>] dm_exception_store_create+0x1d5/0x240 [dm_snapshot] [ 1959.211986] [<ffffffffa040d310>] snapshot_ctr+0x140/0x630 [dm_snapshot] [ 1959.219469] [<ffffffffa0005c44>] ? dm_split_args+0x64/0x150 [dm_mod] [ 1959.226656] [<ffffffffa0005ea7>] dm_table_add_target+0x177/0x440 [dm_mod] [ 1959.234328] [<ffffffffa0009203>] table_load+0x143/0x370 [dm_mod] [ 1959.241129] [<ffffffffa00090c0>] ? retrieve_status+0x1b0/0x1b0 [dm_mod] [ 1959.248607] [<ffffffffa0009e35>] ctl_ioctl+0x255/0x4d0 [dm_mod] [ 1959.255307] [<ffffffff813304e2>] ? memzero_explicit+0x12/0x20 [ 1959.261816] [<ffffffffa000a0c3>] dm_ctl_ioctl+0x13/0x20 [dm_mod] [ 1959.268615] [<ffffffff81215eb6>] do_vfs_ioctl+0xa6/0x5c0 [ 1959.274637] [<ffffffff81120d2f>] ? __audit_syscall_entry+0xaf/0x100 [ 1959.281726] [<ffffffff81003176>] ? do_audit_syscall_entry+0x66/0x70 [ 1959.288814] [<ffffffff81216449>] SyS_ioctl+0x79/0x90 [ 1959.294450] [<ffffffff8167e4ae>] entry_SYSCALL_64_fastpath+0x12/0x71 ... [ 1959.323277] RIP [<ffffffffa040efba>] dm_exception_store_set_chunk_size+0x7a/0x110 [dm_snapshot] [ 1959.333090] RSP <ffff88032a957b30> [ 1959.336978] CR2: 0000000000000098 [ 1959.344121] ---[ end trace b049991ccad1169e ]--- Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1195899 Cc: stable@vger.kernel.org Signed-off-by:
Ding Xiang <dingxiang@huawei.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Joe Thornber authored
smq seems to be performing better than the old mq policy in all situations, as well as using a quarter of the memory. Make 'mq' an alias for 'smq' when choosing a cache policy. The tunables that were present for the old mq are faked, and have no effect. mq should be considered deprecated now. Signed-off-by:
Joe Thornber <ejt@redhat.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Bob Liu authored
md->queue and q are the same thing in dm_old_init_request_queue() and dm_mq_init_request_queue(). Also drop the temporary 'struct request_queue *q' in dm_old_init_request_queue(). Signed-off-by:
Bob Liu <bob.liu@oracle.com> Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Saves 16 bytes by eliminating 4 4byte holes but more importantly: numerous members that crossed cachelines were fixed. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Change the map pointer in 'struct mapped_device' from 'struct dm_table __rcu *' to 'void __rcu *' to avoid the need for the dummy definition. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Allows user to control which NUMA node the memory for DM device structures (e.g. mapped_device, request_queue, gendisk, blk_mq_tag_set) is allocated from. Defaults to NUMA_NO_NODE (-1). Allowable range is from -1 until the last online NUMA node id. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
fail_path() will print a "Failing path ..." message but reinstate_path() doesn't print a "Reinstating path ...". Add that message to reinstate_path() to add symmetry and aid system debugging. Remove reinstate_path()'s check for the path_selector providing .reinstate_path hook. All path selectors provide this and any future ones must too. activate_path() calls pg_init_done() with SCSI_DH_DEV_OFFLINED but pg_init_done() doesn't expicitly handle it in its swicth statement. Add SCSI_DH_DEV_OFFLINED to the default case. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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- 23 Feb, 2016 15 commits
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Now that dm-mpath core is lockless in the per-IO fast path it is critical, for performance, to have the .select_path hook (rr_select_path) also be as lockless as possible. The new percpu members of 'struct selector' allow for lockless support of 'repeat_count' governed repeat use of a previously selected path. If a path fails while it is 'current_path' the worst case is concurrent IO might be mapped to the failed path until the .fail_path hook (rr_fail_path) is called. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
If a path selector has any use for a repeat_count it should be handled locally and not depend on the dm-mpath core to be concerned with it. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Proper locking of the lists used by the path selectors should be handled within the selectors (relying on dm-mpath.c code's use of the m->lock spinlock was reckless). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Preparation for making __multipath_map() avoid taking the m->lock spinlock -- in favor of using RCU locking. repeat_count was primarily for bio-based DM multipath's benefit. There is really no need for it anymore now that DM multipath is request-based. As such, repeat_count > 1 is no longer honored and a warning is displayed if the user attempts to use a value > 1. This is a temporary change for the round-robin path-selector (as a later commit will restore its support for repeat_count > 1). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
There isn't any need to support both old .request_fn and blk-mq paths in the blk-mq specific portion of __multipath_map(). Call blk_mq_alloc_request() directly rather than use blk_get_request(). Similarly, call blk_mq_free_request(), rather than blk_put_request(), in multipath_release_clone(). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Refactor and rename existing interfaces to be more specific and self-documenting. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Allow the multipath target to avoid making small allocations for each 'struct dm_mpath_io' that is needed for each request. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
This will allow DM multipath to use a portion of the blk-mq pdu space for target data (e.g. struct dm_mpath_io). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Request-based DM will also make use of per_bio_data_size. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Rename various methods to have either a "dm_old" or "dm_mq" prefix. Improve code comments to assist with understanding the duality of code that handles both "dm_old" and "dm_mq" cases. It is no much easier to quickly look at the code and _know_ that a given method is either 1) "dm_old" only 2) "dm_mq" only 3) common to both. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Remove all fiddley code that propped up this support for a blk-mq request-queue ontop of all .request_fn devices. Testing has proven this niche request-based dm-mq mode to be buggy, when testing fault tolerance with DM multipath, and there is no point trying to preserve it. Should help improve efficiency of pure dm-mq code and make code maintenance less delicate. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
old_stop_queue() was checking blk_queue_stopped() without holding the q->queue_lock. dm_requeue_original_request() needed to check blk_queue_stopped(), with q->queue_lock held, before calling blk_mq_kick_requeue_list(). And a side-effect of that change is start_queue() must also call blk_mq_kick_requeue_list(). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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- 22 Feb, 2016 9 commits
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Mike Snitzer authored
The blk_mq_tag_set is only needed for dm-mq support. There is point wasting space in 'struct mapped_device' for non-dm-mq devices. Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> # check kzalloc return
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Mike Snitzer authored
Allow user to change these values via module params or sysfs. 'dm_mq_nr_hw_queues' defaults to 1 (max 32). 'dm_mq_queue_depth' defaults to 2048 (up from 64, which proved far too small under moderate sized workloads -- the dm-multipath device would continuously block waiting for tags (requests) to become available). The maximum is BLK_MQ_MAX_DEPTH (currently 10240). Keep in mind the total number of pre-allocated requests per request-based dm-mq device is 'dm_mq_nr_hw_queues' * 'dm_mq_queue_depth' (currently 2048). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
DM multipath is the only request-based DM target -- which only supports tables with a single target that is immutable. Leverage this fact in dm_request_fn(). Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
DM multipath is the only dm-mq target. But that aside, request-based DM only supports tables with a single target that is immutable. Leverage this fact in dm_mq_queue_rq() by using the 'immutable_target' stored in the mapped_device when the table was made active. This saves the need to even take the read-side of the SRCU via dm_{get,put}_live_table. If the active DM table does not have an immutable target (e.g. "error" target was swapped in) then fallback to the slow-path where the target is looked up from the live table. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
The DM_TARGET_WILDCARD feature indicates that the "error" target may replace any target; even immutable targets. This feature will be useful to preserve the ability to replace the "multipath" target even once it is formally converted over to having the DM_TARGET_IMMUTABLE feature. Also, implicit in the DM_TARGET_WILDCARD feature flag being set is that .map, .map_rq, .clone_and_map_rq and .release_clone_rq are all defined in the target_type. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
The request-based DM support for checking queue congestion doesn't require access to the live DM table. Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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Mike Snitzer authored
Request-based DM's blk-mq support (dm-mq) was reported to be 50% slower than if an underlying null_blk device were used directly. One of the reasons for this drop in performance is that blk_insert_clone_request() was calling blk_mq_insert_request() with @async=true. This forced the use of kblockd_schedule_delayed_work_on() to run the blk-mq hw queues which ushered in ping-ponging between process context (fio in this case) and kblockd's kworker to submit the cloned request. The ftrace function_graph tracer showed: kworker-2013 => fio-12190 fio-12190 => kworker-2013 ... kworker-2013 => fio-12190 fio-12190 => kworker-2013 ... Fixing blk_insert_clone_request()'s blk_mq_insert_request() call to _not_ use kblockd to submit the cloned requests isn't enough to eliminate the observed context switches. In addition to this dm-mq specific blk-core fix, there are 2 DM core fixes to dm-mq that (when paired with the blk-core fix) completely eliminate the observed context switching: 1) don't blk_mq_run_hw_queues in blk-mq request completion Motivated by desire to reduce overhead of dm-mq, punting to kblockd just increases context switches. In my testing against a really fast null_blk device there was no benefit to running blk_mq_run_hw_queues() on completion (and no other blk-mq driver does this). So hopefully this change doesn't induce the need for yet another revert like commit 621739b0 ! 2) use blk_mq_complete_request() in dm_complete_request() blk_complete_request() doesn't offer the traditional q->mq_ops vs .request_fn branching pattern that other historic block interfaces do (e.g. blk_get_request). Using blk_mq_complete_request() for blk-mq requests is important for performance. It should be noted that, like blk_complete_request(), blk_mq_complete_request() doesn't natively handle partial completions -- but the request-based DM-multipath target does provide the required partial completion support by dm.c:end_clone_bio() triggering requeueing of the request via dm-mpath.c:multipath_end_io()'s return of DM_ENDIO_REQUEUE. dm-mq fix #2 is _much_ more important than #1 for eliminating the context switches. Before: cpu : usr=15.10%, sys=59.39%, ctx=7905181, majf=0, minf=475 After: cpu : usr=20.60%, sys=79.35%, ctx=2008, majf=0, minf=472 With these changes multithreaded async read IOPs improved from ~950K to ~1350K for this dm-mq stacked on null_blk test-case. The raw read IOPs of the underlying null_blk device for the same workload is ~1950K. Fixes: 7fb4898e ("block: add blk-mq support to blk_insert_cloned_request()") Fixes: bfebd1cd ("dm: add full blk-mq support to request-based DM") Cc: stable@vger.kernel.org # 4.1+ Reported-by:
Sagi Grimberg <sagig@dev.mellanox.co.il> Signed-off-by:
Mike Snitzer <snitzer@redhat.com> Acked-by:
Jens Axboe <axboe@kernel.dk>
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Mike Snitzer authored
Rename dm_get_live_table_for_ioctl to dm_grab_bdev_for_ioctl and have it do the dm_{get,put}_live_table() rather than split those operations. The dm_grab_bdev_for_ioctl() callers only care about the block_device associated with a singleton DM device so there isn't any need to retain a reference to the live DM table. It is sufficient to: 1) dm_get_live_table() 2) bdgrab() the bdev associated with the singleton table's target 3) dm_put_live_table() 4) bdput() the bdev Signed-off-by:
Mike Snitzer <snitzer@redhat.com>
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