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db2351eb |
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26-May-2021 |
Mikulas Patocka <mpatocka@redhat.com> |
dm kcopyd: avoid useless atomic operations The functions set_bit and clear_bit are atomic. We don't need atomicity when making flags for dm-kcopyd. So, change them to direct manipulation of the flags. Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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#
174364f6 |
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07-Jul-2020 |
Damien Le Moal <damien.lemoal@wdc.com> |
dm zoned: Fix zone reclaim trigger Only triggering reclaim based on the percentage of unmapped cache zones can fail to detect cases where reclaim is needed, e.g. if the target has only 2 or 3 cache zones and only one unmapped cache zone, the percentage of free cache zones is higher than DMZ_RECLAIM_LOW_UNMAP_ZONES (30%) and reclaim does not trigger. This problem, combined with the fact that dmz_schedule_reclaim() is called from dmz_handle_bio() without the map lock held, leads to a race between zone allocation and dmz_should_reclaim() result. Depending on the workload applied, this race can lead to the write path waiting forever for a free zone without reclaim being triggered. Fix this by moving dmz_schedule_reclaim() inside dmz_alloc_zone() under the map lock. This results in checking the need for zone reclaim whenever a new data or buffer zone needs to be allocated. Also fix dmz_reclaim_percentage() to always return 0 if the number of unmapped cache (or random) zones is less than or equal to 1. Suggested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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#
ce34c9b4 |
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02-Jul-2020 |
Wei Yongjun <weiyongjun1@huawei.com> |
dm zoned: fix unused but set variable warnings Fix unused but set variable warnings: drivers/md/dm-zoned-reclaim.c:504:42: warning: variable nr_rnd set but not used [-Wunused-but-set-variable] 504 | unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0; | ^~~~~~ drivers/md/dm-zoned-reclaim.c:504:24: warning: variable nr_unmap_rnd set but not used [-Wunused-but-set-variable] 504 | unsigned int p_unmap, nr_unmap_rnd = 0, nr_rnd = 0; | ^~~~~~~~~~~~ Fixes: f97809aec589 ("dm zoned: per-device reclaim") Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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c69cb1d1 |
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07-Jun-2020 |
Damien Le Moal <damien.lemoal@wdc.com> |
dm zoned: fix uninitialized pointer dereference Make sure that the local variable rzone in dmz_do_reclaim() is always initialized before being used for printing debug messages. Fixes: f97809aec589 ("dm zoned: per-device reclaim") Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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69875d44 |
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02-Jun-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: select reclaim zone based on device index per-device reclaim should select zones on that device only. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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22c1ef66 |
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02-Jun-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: allocate zone by device index When allocating a zone, pass in an indicator on which device the zone should be allocated; this increases performance for a multi-device setup because reclaim will now allocate zones on the device for which reclaim is running. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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bd82fdab |
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02-Jun-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: move random and sequential zones into struct dmz_dev Random and sequential zones should be part of the respective device structure to make arbitration between devices possible. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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f97809ae |
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02-Jun-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: per-device reclaim Instead of having one reclaim workqueue for the entire set we should be allocating a reclaim workqueue per device; doing so will reduce contention and should boost performance for a multi-device setup. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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8f22272a |
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02-Jun-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: add device pointer to struct dm_zone Add a pointer, to the containing device, within struct dm_zone and kill dmz_zone_to_dev(). Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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c3ff479d |
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02-Jun-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: improve logging messages for reclaim Instead of just reporting the errno, add some more verbose debugging message in the reclaim path. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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a16b7dee |
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19-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: terminate reclaim on congestion When dmz_get_chunk_mapping() selects a zone which is under reclaim we should terminate the reclaim copy process. Since we're changing the zone itself, reclaim needs to run afterwards again anyway. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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c5c78859 |
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19-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: start reclaim with sequential zones Sequential zones perform better for reclaim, so start off using them and only use random zones as a fallback when cache zones are present. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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90a9b869 |
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19-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: reclaim random zones when idle When the system is idle we should be starting reclaiming random zones, too. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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34f5affd |
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19-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: separate random and cache zones Instead of lumping emulated zones together with random zones we should be handling them as separate 'cache' zones. This improves code readability and allows an easier implementation of different cache policies. Also add additional allocation flags, to separate the type (cache, random, or sequential) from the purpose (eg reclaim). Also switch the allocation policy to not use random zones as buffer zones if cache zones are present. This avoids a performance drop when all cache zones are used. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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489dc0f0 |
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19-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: return NULL if dmz_get_zone_for_reclaim() fails to find a zone The only case where dmz_get_zone_for_reclaim() cannot return a zone is if the respective lists are empty. So we should just return a simple NULL value here as we really don't have an error code which would make sense. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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49de3b7d |
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14-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: remove spurious newlines from debugging messages DMDEBUG will already add a newline to the logging messages, so we shouldn't be adding it to the message itself. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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6c805f77 |
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11-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: remove 'dev' argument from reclaim Use the dmz_zone_to_dev() mapping function to remove the 'dev' argument from reclaim. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bob Liu <bob.liu@oracle.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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d0e21ce4 |
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11-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: Introduce dmz_dev_is_dying() and dmz_check_dev() Introduce accessors dmz_dev_is_dying() and dmz_check_dev() to avoid having to reference the devices directly. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bob Liu <bob.liu@oracle.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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2234e732 |
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11-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: introduce dmz_metadata_label() to format device name Introduce dmz_metadata_label() to format the device-mapper device name and use it instead of the device name of the underlying device. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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36820560 |
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11-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: move fields from struct dmz_dev to dmz_metadata Move fields from the device structure into the metadata structure and provide accessor functions. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Bob Liu <bob.liu@oracle.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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b7122873 |
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11-May-2020 |
Hannes Reinecke <hare@suse.de> |
dm zoned: store zone id within the zone structure and kill dmz_id() Instead of calculating the zone index by the offset within the zone array store the index within the structure itself. With that the helper dmz_id() is pointless and can be replaced with accessing the ->id value directly. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Bob Liu <bob.liu@oracle.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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e7fad909 |
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06-Nov-2019 |
Dmitry Fomichev <dmitry.fomichev@wdc.com> |
dm zoned: reduce overhead of backing device checks Commit 75d66ffb48efb3 added backing device health checks and as a part of these checks, check_events() block ops template call is invoked in dm-zoned mapping path as well as in reclaim and flush path. Calling check_events() with ATA or SCSI backing devices introduces a blocking scsi_test_unit_ready() call being made in sd_check_events(). Even though the overhead of calling scsi_test_unit_ready() is small for ATA zoned devices, it is much larger for SCSI and it affects performance in a very negative way. Fix this performance regression by executing check_events() only in case of any I/O errors. The function dmz_bdev_is_dying() is modified to call only blk_queue_dying(), while calls to check_events() are made in a new helper function, dmz_check_bdev(). Reported-by: zhangxiaoxu <zhangxiaoxu5@huawei.com> Fixes: 75d66ffb48efb3 ("dm zoned: properly handle backing device failure") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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ad1bd578 |
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02-Aug-2019 |
Dmitry Fomichev <dmitry.fomichev@wdc.com> |
dm zoned: fix a few typos Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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bae9a0aa |
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02-Aug-2019 |
Dmitry Fomichev <dmitry.fomichev@wdc.com> |
dm zoned: add SPDX license identifiers Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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75d66ffb |
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10-Aug-2019 |
Dmitry Fomichev <dmitry.fomichev@wdc.com> |
dm zoned: properly handle backing device failure dm-zoned is observed to lock up or livelock in case of hardware failure or some misconfiguration of the backing zoned device. This patch adds a new dm-zoned target function that checks the status of the backing device. If the request queue of the backing device is found to be in dying state or the SCSI backing device enters offline state, the health check code sets a dm-zoned target flag prompting all further incoming I/O to be rejected. In order to detect backing device failures timely, this new function is called in the request mapping path, at the beginning of every reclaim run and before performing any metadata I/O. The proper way out of this situation is to do dmsetup remove <dm-zoned target> and recreate the target when the problem with the backing device is resolved. Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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b234c6d7 |
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10-Aug-2019 |
Dmitry Fomichev <dmitry.fomichev@wdc.com> |
dm zoned: improve error handling in reclaim There are several places in reclaim code where errors are not propagated to the main function, dmz_reclaim(). This function is responsible for unlocking zones that might be still locked at the end of any failed reclaim iterations. As the result, some device zones may be left permanently locked for reclaim, degrading target's capability to reclaim zones. This patch fixes these issues as follows - Make sure that dmz_reclaim_buf(), dmz_reclaim_seq_data() and dmz_reclaim_rnd_data() return error codes to the caller. dmz_reclaim() function is renamed to dmz_do_reclaim() to avoid clashing with "struct dmz_reclaim" and is modified to return the error to the caller. dmz_get_zone_for_reclaim() now returns an error instead of NULL pointer and reclaim code checks for that error. Error logging/debug messages are added where necessary. Fixes: 3b1a94c88b79 ("dm zoned: drive-managed zoned block device target") Cc: stable@vger.kernel.org Signed-off-by: Dmitry Fomichev <dmitry.fomichev@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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7209049d |
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31-Jul-2018 |
Mike Snitzer <snitzer@redhat.com> |
dm kcopyd: return void from dm_kcopyd_copy() dm_kcopyd_copy() only ever returns 0 so there is no need for callers to account for possible failure. Same goes for dm_kcopyd_zero(). Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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4218a955 |
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24-Jul-2017 |
Damien Le Moal <damien.lemoal@wdc.com> |
dm zoned: use GFP_NOIO in I/O path Use GFP_NOIO for memory allocations in the I/O path. Other memory allocations in the initialization path can use GFP_KERNEL. Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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3b1a94c8 |
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07-Jun-2017 |
Damien Le Moal <damien.lemoal@wdc.com> |
dm zoned: drive-managed zoned block device target The dm-zoned device mapper target provides transparent write access to zoned block devices (ZBC and ZAC compliant block devices). dm-zoned hides to the device user (a file system or an application doing raw block device accesses) any constraint imposed on write requests by the device, equivalent to a drive-managed zoned block device model. Write requests are processed using a combination of on-disk buffering using the device conventional zones and direct in-place processing for requests aligned to a zone sequential write pointer position. A background reclaim process implemented using dm_kcopyd_copy ensures that conventional zones are always available for executing unaligned write requests. The reclaim process overhead is minimized by managing buffer zones in a least-recently-written order and first targeting the oldest buffer zones. Doing so, blocks under regular write access (such as metadata blocks of a file system) remain stored in conventional zones, resulting in no apparent overhead. dm-zoned implementation focus on simplicity and on minimizing overhead (CPU, memory and storage overhead). For a 14TB host-managed disk with 256 MB zones, dm-zoned memory usage per disk instance is at most about 3 MB and as little as 5 zones will be used internally for storing metadata and performing buffer zone reclaim operations. This is achieved using zone level indirection rather than a full block indirection system for managing block movement between zones. dm-zoned primary target is host-managed zoned block devices but it can also be used with host-aware device models to mitigate potential device-side performance degradation due to excessive random writing. Zoned block devices can be formatted and checked for use with the dm-zoned target using the dmzadm utility available at: https://github.com/hgst/dm-zoned-tools Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> [Mike Snitzer partly refactored Damien's original work to cleanup the code] Signed-off-by: Mike Snitzer <snitzer@redhat.com>
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