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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-19 21:00:37 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-06-19 21:00:37 +0000 |
commit | 94ac2ab3fff96814d7460a27a0e9d004abbd4128 (patch) | |
tree | 9a4eb8cc234b540b0f4b93363109cdd37a20540b /drivers/md/dm-vdo/io-submitter.c | |
parent | Adding debian version 6.8.12-1. (diff) | |
download | linux-94ac2ab3fff96814d7460a27a0e9d004abbd4128.tar.xz linux-94ac2ab3fff96814d7460a27a0e9d004abbd4128.zip |
Merging upstream version 6.9.2.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/md/dm-vdo/io-submitter.c')
-rw-r--r-- | drivers/md/dm-vdo/io-submitter.c | 477 |
1 files changed, 477 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/io-submitter.c b/drivers/md/dm-vdo/io-submitter.c new file mode 100644 index 0000000000..9a3716bb3c --- /dev/null +++ b/drivers/md/dm-vdo/io-submitter.c @@ -0,0 +1,477 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2023 Red Hat + */ + +#include "io-submitter.h" + +#include <linux/bio.h> +#include <linux/kernel.h> +#include <linux/mutex.h> + +#include "memory-alloc.h" +#include "permassert.h" + +#include "data-vio.h" +#include "logger.h" +#include "types.h" +#include "vdo.h" +#include "vio.h" + +/* + * Submission of bio operations to the underlying storage device will go through a separate work + * queue thread (or more than one) to prevent blocking in other threads if the storage device has a + * full queue. The plug structure allows that thread to do better batching of requests to make the + * I/O more efficient. + * + * When multiple worker threads are used, a thread is chosen for a I/O operation submission based + * on the PBN, so a given PBN will consistently wind up on the same thread. Flush operations are + * assigned round-robin. + * + * The map (protected by the mutex) collects pending I/O operations so that the worker thread can + * reorder them to try to encourage I/O request merging in the request queue underneath. + */ +struct bio_queue_data { + struct vdo_work_queue *queue; + struct blk_plug plug; + struct int_map *map; + struct mutex lock; + unsigned int queue_number; +}; + +struct io_submitter { + unsigned int num_bio_queues_used; + unsigned int bio_queue_rotation_interval; + struct bio_queue_data bio_queue_data[]; +}; + +static void start_bio_queue(void *ptr) +{ + struct bio_queue_data *bio_queue_data = ptr; + + blk_start_plug(&bio_queue_data->plug); +} + +static void finish_bio_queue(void *ptr) +{ + struct bio_queue_data *bio_queue_data = ptr; + + blk_finish_plug(&bio_queue_data->plug); +} + +static const struct vdo_work_queue_type bio_queue_type = { + .start = start_bio_queue, + .finish = finish_bio_queue, + .max_priority = BIO_Q_MAX_PRIORITY, + .default_priority = BIO_Q_DATA_PRIORITY, +}; + +/** + * count_all_bios() - Determine which bio counter to use. + * @vio: The vio associated with the bio. + * @bio: The bio to count. + */ +static void count_all_bios(struct vio *vio, struct bio *bio) +{ + struct atomic_statistics *stats = &vio->completion.vdo->stats; + + if (is_data_vio(vio)) { + vdo_count_bios(&stats->bios_out, bio); + return; + } + + vdo_count_bios(&stats->bios_meta, bio); + if (vio->type == VIO_TYPE_RECOVERY_JOURNAL) + vdo_count_bios(&stats->bios_journal, bio); + else if (vio->type == VIO_TYPE_BLOCK_MAP) + vdo_count_bios(&stats->bios_page_cache, bio); +} + +/** + * assert_in_bio_zone() - Assert that a vio is in the correct bio zone and not in interrupt + * context. + * @vio: The vio to check. + */ +static void assert_in_bio_zone(struct vio *vio) +{ + VDO_ASSERT_LOG_ONLY(!in_interrupt(), "not in interrupt context"); + assert_vio_in_bio_zone(vio); +} + +/** + * send_bio_to_device() - Update stats and tracing info, then submit the supplied bio to the OS for + * processing. + * @vio: The vio associated with the bio. + * @bio: The bio to submit to the OS. + */ +static void send_bio_to_device(struct vio *vio, struct bio *bio) +{ + struct vdo *vdo = vio->completion.vdo; + + assert_in_bio_zone(vio); + atomic64_inc(&vdo->stats.bios_submitted); + count_all_bios(vio, bio); + bio_set_dev(bio, vdo_get_backing_device(vdo)); + submit_bio_noacct(bio); +} + +/** + * vdo_submit_vio() - Submits a vio's bio to the underlying block device. May block if the device + * is busy. This callback should be used by vios which did not attempt to merge. + */ +void vdo_submit_vio(struct vdo_completion *completion) +{ + struct vio *vio = as_vio(completion); + + send_bio_to_device(vio, vio->bio); +} + +/** + * get_bio_list() - Extract the list of bios to submit from a vio. + * @vio: The vio submitting I/O. + * + * The list will always contain at least one entry (the bio for the vio on which it is called), but + * other bios may have been merged with it as well. + * + * Return: bio The head of the bio list to submit. + */ +static struct bio *get_bio_list(struct vio *vio) +{ + struct bio *bio; + struct io_submitter *submitter = vio->completion.vdo->io_submitter; + struct bio_queue_data *bio_queue_data = &(submitter->bio_queue_data[vio->bio_zone]); + + assert_in_bio_zone(vio); + + mutex_lock(&bio_queue_data->lock); + vdo_int_map_remove(bio_queue_data->map, + vio->bios_merged.head->bi_iter.bi_sector); + vdo_int_map_remove(bio_queue_data->map, + vio->bios_merged.tail->bi_iter.bi_sector); + bio = vio->bios_merged.head; + bio_list_init(&vio->bios_merged); + mutex_unlock(&bio_queue_data->lock); + + return bio; +} + +/** + * submit_data_vio() - Submit a data_vio's bio to the storage below along with + * any bios that have been merged with it. + * + * Context: This call may block and so should only be called from a bio thread. + */ +static void submit_data_vio(struct vdo_completion *completion) +{ + struct bio *bio, *next; + struct vio *vio = as_vio(completion); + + assert_in_bio_zone(vio); + for (bio = get_bio_list(vio); bio != NULL; bio = next) { + next = bio->bi_next; + bio->bi_next = NULL; + send_bio_to_device((struct vio *) bio->bi_private, bio); + } +} + +/** + * get_mergeable_locked() - Attempt to find an already queued bio that the current bio can be + * merged with. + * @map: The bio map to use for merging. + * @vio: The vio we want to merge. + * @back_merge: Set to true for a back merge, false for a front merge. + * + * There are two types of merging possible, forward and backward, which are distinguished by a flag + * that uses kernel elevator terminology. + * + * Return: the vio to merge to, NULL if no merging is possible. + */ +static struct vio *get_mergeable_locked(struct int_map *map, struct vio *vio, + bool back_merge) +{ + struct bio *bio = vio->bio; + sector_t merge_sector = bio->bi_iter.bi_sector; + struct vio *vio_merge; + + if (back_merge) + merge_sector -= VDO_SECTORS_PER_BLOCK; + else + merge_sector += VDO_SECTORS_PER_BLOCK; + + vio_merge = vdo_int_map_get(map, merge_sector); + + if (vio_merge == NULL) + return NULL; + + if (vio->completion.priority != vio_merge->completion.priority) + return NULL; + + if (bio_data_dir(bio) != bio_data_dir(vio_merge->bio)) + return NULL; + + if (bio_list_empty(&vio_merge->bios_merged)) + return NULL; + + if (back_merge) { + return (vio_merge->bios_merged.tail->bi_iter.bi_sector == merge_sector ? + vio_merge : NULL); + } + + return (vio_merge->bios_merged.head->bi_iter.bi_sector == merge_sector ? + vio_merge : NULL); +} + +static int map_merged_vio(struct int_map *bio_map, struct vio *vio) +{ + int result; + sector_t bio_sector; + + bio_sector = vio->bios_merged.head->bi_iter.bi_sector; + result = vdo_int_map_put(bio_map, bio_sector, vio, true, NULL); + if (result != VDO_SUCCESS) + return result; + + bio_sector = vio->bios_merged.tail->bi_iter.bi_sector; + return vdo_int_map_put(bio_map, bio_sector, vio, true, NULL); +} + +static int merge_to_prev_tail(struct int_map *bio_map, struct vio *vio, + struct vio *prev_vio) +{ + vdo_int_map_remove(bio_map, prev_vio->bios_merged.tail->bi_iter.bi_sector); + bio_list_merge(&prev_vio->bios_merged, &vio->bios_merged); + return map_merged_vio(bio_map, prev_vio); +} + +static int merge_to_next_head(struct int_map *bio_map, struct vio *vio, + struct vio *next_vio) +{ + /* + * Handle "next merge" and "gap fill" cases the same way so as to reorder bios in a way + * that's compatible with using funnel queues in work queues. This avoids removing an + * existing completion. + */ + vdo_int_map_remove(bio_map, next_vio->bios_merged.head->bi_iter.bi_sector); + bio_list_merge_head(&next_vio->bios_merged, &vio->bios_merged); + return map_merged_vio(bio_map, next_vio); +} + +/** + * try_bio_map_merge() - Attempt to merge a vio's bio with other pending I/Os. + * @vio: The vio to merge. + * + * Currently this is only used for data_vios, but is broken out for future use with metadata vios. + * + * Return: whether or not the vio was merged. + */ +static bool try_bio_map_merge(struct vio *vio) +{ + int result; + bool merged = true; + struct bio *bio = vio->bio; + struct vio *prev_vio, *next_vio; + struct vdo *vdo = vio->completion.vdo; + struct bio_queue_data *bio_queue_data = + &vdo->io_submitter->bio_queue_data[vio->bio_zone]; + + bio->bi_next = NULL; + bio_list_init(&vio->bios_merged); + bio_list_add(&vio->bios_merged, bio); + + mutex_lock(&bio_queue_data->lock); + prev_vio = get_mergeable_locked(bio_queue_data->map, vio, true); + next_vio = get_mergeable_locked(bio_queue_data->map, vio, false); + if (prev_vio == next_vio) + next_vio = NULL; + + if ((prev_vio == NULL) && (next_vio == NULL)) { + /* no merge. just add to bio_queue */ + merged = false; + result = vdo_int_map_put(bio_queue_data->map, + bio->bi_iter.bi_sector, + vio, true, NULL); + } else if (next_vio == NULL) { + /* Only prev. merge to prev's tail */ + result = merge_to_prev_tail(bio_queue_data->map, vio, prev_vio); + } else { + /* Only next. merge to next's head */ + result = merge_to_next_head(bio_queue_data->map, vio, next_vio); + } + mutex_unlock(&bio_queue_data->lock); + + /* We don't care about failure of int_map_put in this case. */ + VDO_ASSERT_LOG_ONLY(result == VDO_SUCCESS, "bio map insertion succeeds"); + return merged; +} + +/** + * vdo_submit_data_vio() - Submit I/O for a data_vio. + * @data_vio: the data_vio for which to issue I/O. + * + * If possible, this I/O will be merged other pending I/Os. Otherwise, the data_vio will be sent to + * the appropriate bio zone directly. + */ +void vdo_submit_data_vio(struct data_vio *data_vio) +{ + if (try_bio_map_merge(&data_vio->vio)) + return; + + launch_data_vio_bio_zone_callback(data_vio, submit_data_vio); +} + +/** + * __submit_metadata_vio() - Submit I/O for a metadata vio. + * @vio: the vio for which to issue I/O + * @physical: the physical block number to read or write + * @callback: the bio endio function which will be called after the I/O completes + * @error_handler: the handler for submission or I/O errors (may be NULL) + * @operation: the type of I/O to perform + * @data: the buffer to read or write (may be NULL) + * + * The vio is enqueued on a vdo bio queue so that bio submission (which may block) does not block + * other vdo threads. + * + * That the error handler will run on the correct thread is only true so long as the thread calling + * this function, and the thread set in the endio callback are the same, as well as the fact that + * no error can occur on the bio queue. Currently this is true for all callers, but additional care + * will be needed if this ever changes. + */ +void __submit_metadata_vio(struct vio *vio, physical_block_number_t physical, + bio_end_io_t callback, vdo_action_fn error_handler, + blk_opf_t operation, char *data) +{ + int result; + struct vdo_completion *completion = &vio->completion; + const struct admin_state_code *code = vdo_get_admin_state(completion->vdo); + + + VDO_ASSERT_LOG_ONLY(!code->quiescent, "I/O not allowed in state %s", code->name); + VDO_ASSERT_LOG_ONLY(vio->bio->bi_next == NULL, "metadata bio has no next bio"); + + vdo_reset_completion(completion); + completion->error_handler = error_handler; + result = vio_reset_bio(vio, data, callback, operation | REQ_META, physical); + if (result != VDO_SUCCESS) { + continue_vio(vio, result); + return; + } + + vdo_set_completion_callback(completion, vdo_submit_vio, + get_vio_bio_zone_thread_id(vio)); + vdo_launch_completion_with_priority(completion, get_metadata_priority(vio)); +} + +/** + * vdo_make_io_submitter() - Create an io_submitter structure. + * @thread_count: Number of bio-submission threads to set up. + * @rotation_interval: Interval to use when rotating between bio-submission threads when enqueuing + * completions. + * @max_requests_active: Number of bios for merge tracking. + * @vdo: The vdo which will use this submitter. + * @io_submitter: pointer to the new data structure. + * + * Return: VDO_SUCCESS or an error. + */ +int vdo_make_io_submitter(unsigned int thread_count, unsigned int rotation_interval, + unsigned int max_requests_active, struct vdo *vdo, + struct io_submitter **io_submitter_ptr) +{ + unsigned int i; + struct io_submitter *io_submitter; + int result; + + result = vdo_allocate_extended(struct io_submitter, thread_count, + struct bio_queue_data, "bio submission data", + &io_submitter); + if (result != VDO_SUCCESS) + return result; + + io_submitter->bio_queue_rotation_interval = rotation_interval; + + /* Setup for each bio-submission work queue */ + for (i = 0; i < thread_count; i++) { + struct bio_queue_data *bio_queue_data = &io_submitter->bio_queue_data[i]; + + mutex_init(&bio_queue_data->lock); + /* + * One I/O operation per request, but both first & last sector numbers. + * + * If requests are assigned to threads round-robin, they should be distributed + * quite evenly. But if they're assigned based on PBN, things can sometimes be very + * uneven. So for now, we'll assume that all requests *may* wind up on one thread, + * and thus all in the same map. + */ + result = vdo_int_map_create(max_requests_active * 2, + &bio_queue_data->map); + if (result != VDO_SUCCESS) { + /* + * Clean up the partially initialized bio-queue entirely and indicate that + * initialization failed. + */ + vdo_log_error("bio map initialization failed %d", result); + vdo_cleanup_io_submitter(io_submitter); + vdo_free_io_submitter(io_submitter); + return result; + } + + bio_queue_data->queue_number = i; + result = vdo_make_thread(vdo, vdo->thread_config.bio_threads[i], + &bio_queue_type, 1, (void **) &bio_queue_data); + if (result != VDO_SUCCESS) { + /* + * Clean up the partially initialized bio-queue entirely and indicate that + * initialization failed. + */ + vdo_int_map_free(vdo_forget(bio_queue_data->map)); + vdo_log_error("bio queue initialization failed %d", result); + vdo_cleanup_io_submitter(io_submitter); + vdo_free_io_submitter(io_submitter); + return result; + } + + bio_queue_data->queue = vdo->threads[vdo->thread_config.bio_threads[i]].queue; + io_submitter->num_bio_queues_used++; + } + + *io_submitter_ptr = io_submitter; + + return VDO_SUCCESS; +} + +/** + * vdo_cleanup_io_submitter() - Tear down the io_submitter fields as needed for a physical layer. + * @io_submitter: The I/O submitter data to tear down (may be NULL). + */ +void vdo_cleanup_io_submitter(struct io_submitter *io_submitter) +{ + int i; + + if (io_submitter == NULL) + return; + + for (i = io_submitter->num_bio_queues_used - 1; i >= 0; i--) + vdo_finish_work_queue(io_submitter->bio_queue_data[i].queue); +} + +/** + * vdo_free_io_submitter() - Free the io_submitter fields and structure as needed. + * @io_submitter: The I/O submitter data to destroy. + * + * This must be called after vdo_cleanup_io_submitter(). It is used to release resources late in + * the shutdown process to avoid or reduce the chance of race conditions. + */ +void vdo_free_io_submitter(struct io_submitter *io_submitter) +{ + int i; + + if (io_submitter == NULL) + return; + + for (i = io_submitter->num_bio_queues_used - 1; i >= 0; i--) { + io_submitter->num_bio_queues_used--; + /* vdo_destroy() will free the work queue, so just give up our reference to it. */ + vdo_forget(io_submitter->bio_queue_data[i].queue); + vdo_int_map_free(vdo_forget(io_submitter->bio_queue_data[i].map)); + } + vdo_free(io_submitter); +} |