dc6364b517
We don't need to update the original dm request partially when ending
each cloned bio: just update original dm request once when the whole
cloned request is finished. This still allows full support for partial
completion because a new 'completed' counter accounts for incremental
progress as the clone bios complete.
Partial request update can be a bit expensive, so we should try to avoid
it, especially because it is run in softirq context.
Avoiding all the partial request updates fixes both hard lockup and
soft lockups that were easily reproduced while running Laurence's
test[1] on IB/SRP.
BTW, after d4acf3650c ("block: Make blk_mq_delay_kick_requeue_list()
rerun the queue at a quiet time"), we need to make the test more
aggressive for reproducing the lockup:
1) run hammer_write.sh 32 or 64 concurrently.
2) write 8M each time
[1] https://marc.info/?l=linux-block&m=150220185510245&w=2
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
67 lines
1.7 KiB
C
67 lines
1.7 KiB
C
/*
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* Internal header file for device mapper
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*
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* Copyright (C) 2016 Red Hat, Inc. All rights reserved.
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*
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* This file is released under the LGPL.
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*/
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#ifndef DM_RQ_INTERNAL_H
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#define DM_RQ_INTERNAL_H
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#include <linux/bio.h>
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#include <linux/kthread.h>
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#include "dm-stats.h"
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struct mapped_device;
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/*
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* One of these is allocated per request.
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*/
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struct dm_rq_target_io {
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struct mapped_device *md;
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struct dm_target *ti;
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struct request *orig, *clone;
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struct kthread_work work;
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blk_status_t error;
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union map_info info;
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struct dm_stats_aux stats_aux;
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unsigned long duration_jiffies;
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unsigned n_sectors;
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unsigned completed;
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};
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/*
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* For request-based dm - the bio clones we allocate are embedded in these
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* structs.
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*
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* We allocate these with bio_alloc_bioset, using the front_pad parameter when
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* the bioset is created - this means the bio has to come at the end of the
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* struct.
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*/
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struct dm_rq_clone_bio_info {
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struct bio *orig;
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struct dm_rq_target_io *tio;
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struct bio clone;
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};
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bool dm_use_blk_mq_default(void);
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bool dm_use_blk_mq(struct mapped_device *md);
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int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t);
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int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t);
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void dm_mq_cleanup_mapped_device(struct mapped_device *md);
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void dm_start_queue(struct request_queue *q);
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void dm_stop_queue(struct request_queue *q);
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void dm_mq_kick_requeue_list(struct mapped_device *md);
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unsigned dm_get_reserved_rq_based_ios(void);
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ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf);
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ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
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const char *buf, size_t count);
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#endif
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