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(173-166-2-198-newengland.hfc.comcastbusiness.net. [173.166.2.198]) by smtp.gmail.com with ESMTPSA id el14-20020ad459ce000000b0062119a7a7a3sm3086780qvb.4.2023.05.23.14.46.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 23 May 2023 14:46:29 -0700 (PDT) From: "J. corwin Coburn" To: dm-devel@redhat.com, linux-block@vger.kernel.org Date: Tue, 23 May 2023 17:45:24 -0400 Message-Id: <20230523214539.226387-25-corwin@redhat.com> In-Reply-To: <20230523214539.226387-1-corwin@redhat.com> References: <20230523214539.226387-1-corwin@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Subject: [dm-devel] [PATCH v2 24/39] Add the compressed block bin packer. X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: vdo-devel@redhat.com, "J. corwin Coburn" Errors-To: dm-devel-bounces@redhat.com Sender: "dm-devel" X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com When blocks do not deduplicate, vdo will attempt to compress them. Up to 14 compressed blocks may be packed into a single data block (this limitation is imposed by the block map). The packer implements a simple best-fit packing algorithm and also manages the formatting and writing of compressed blocks when bins fill. Signed-off-by: J. corwin Coburn --- drivers/md/dm-vdo/packer.c | 794 +++++++++++++++++++++++++++++++++++++ drivers/md/dm-vdo/packer.h | 123 ++++++ 2 files changed, 917 insertions(+) create mode 100644 drivers/md/dm-vdo/packer.c create mode 100644 drivers/md/dm-vdo/packer.h diff --git a/drivers/md/dm-vdo/packer.c b/drivers/md/dm-vdo/packer.c new file mode 100644 index 00000000000..f9b67777850 --- /dev/null +++ b/drivers/md/dm-vdo/packer.c @@ -0,0 +1,794 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright Red Hat + */ + +#include "packer.h" + +#include +#include + +#include "logger.h" +#include "memory-alloc.h" +#include "permassert.h" +#include "string-utils.h" + +#include "admin-state.h" +#include "completion.h" +#include "constants.h" +#include "data-vio.h" +#include "dedupe.h" +#include "encodings.h" +#include "io-submitter.h" +#include "physical-zone.h" +#include "status-codes.h" +#include "vdo.h" +#include "vio.h" + +static const struct version_number COMPRESSED_BLOCK_1_0 = { + .major_version = 1, + .minor_version = 0, +}; + +enum { + COMPRESSED_BLOCK_1_0_SIZE = 4 + 4 + (2 * VDO_MAX_COMPRESSION_SLOTS), +}; + +/** + * vdo_get_compressed_block_fragment() - Get a reference to a compressed fragment from a compressed + * block. + * @mapping_state [in] The mapping state for the look up. + * @compressed_block [in] The compressed block that was read from disk. + * @fragment_offset [out] The offset of the fragment within a compressed block. + * @fragment_size [out] The size of the fragment. + * + * Return: If a valid compressed fragment is found, VDO_SUCCESS; otherwise, VDO_INVALID_FRAGMENT if + * the fragment is invalid. + */ +int vdo_get_compressed_block_fragment(enum block_mapping_state mapping_state, + struct compressed_block *block, + u16 *fragment_offset, + u16 *fragment_size) +{ + u16 compressed_size; + u16 offset = 0; + unsigned int i; + u8 slot; + struct version_number version; + + if (!vdo_is_state_compressed(mapping_state)) + return VDO_INVALID_FRAGMENT; + + version = vdo_unpack_version_number(block->header.version); + if (!vdo_are_same_version(version, COMPRESSED_BLOCK_1_0)) + return VDO_INVALID_FRAGMENT; + + slot = mapping_state - VDO_MAPPING_STATE_COMPRESSED_BASE; + if (slot >= VDO_MAX_COMPRESSION_SLOTS) + return VDO_INVALID_FRAGMENT; + + compressed_size = __le16_to_cpu(block->header.sizes[slot]); + for (i = 0; i < slot; i++) { + offset += __le16_to_cpu(block->header.sizes[i]); + if (offset >= VDO_COMPRESSED_BLOCK_DATA_SIZE) + return VDO_INVALID_FRAGMENT; + } + + if ((offset + compressed_size) > VDO_COMPRESSED_BLOCK_DATA_SIZE) + return VDO_INVALID_FRAGMENT; + + *fragment_offset = offset; + *fragment_size = compressed_size; + return VDO_SUCCESS; +} + +/** + * assert_on_packer_thread() - Check that we are on the packer thread. + * @packer: The packer. + * @caller: The function which is asserting. + */ +static inline void assert_on_packer_thread(struct packer *packer, const char *caller) +{ + ASSERT_LOG_ONLY((vdo_get_callback_thread_id() == packer->thread_id), + "%s() called from packer thread", caller); +} + +/** + * insert_in_sorted_list() - Insert a bin to the list. + * @packer: The packer. + * @bin: The bin to move to its sorted position. + * + * The list is in ascending order of free space. Since all bins are already in the list, this + * actually moves the bin to the correct position in the list. + */ +static void insert_in_sorted_list(struct packer *packer, struct packer_bin *bin) +{ + struct packer_bin *active_bin; + + list_for_each_entry(active_bin, &packer->bins, list) + if (active_bin->free_space > bin->free_space) { + list_move_tail(&bin->list, &active_bin->list); + return; + } + + list_move_tail(&bin->list, &packer->bins); +} + +/** + * make_bin() - Allocate a bin and put it into the packer's list. + * @packer: The packer. + */ +static int __must_check make_bin(struct packer *packer) +{ + struct packer_bin *bin; + int result; + + result = UDS_ALLOCATE_EXTENDED(struct packer_bin, + VDO_MAX_COMPRESSION_SLOTS, + struct vio *, + __func__, + &bin); + if (result != VDO_SUCCESS) + return result; + + bin->free_space = VDO_COMPRESSED_BLOCK_DATA_SIZE; + INIT_LIST_HEAD(&bin->list); + list_add_tail(&bin->list, &packer->bins); + return VDO_SUCCESS; +} + +/** + * vdo_make_packer() - Make a new block packer. + * + * @vdo: The vdo to which this packer belongs. + * @bin_count: The number of partial bins to keep in memory. + * @packer_ptr: A pointer to hold the new packer. + * + * Return: VDO_SUCCESS or an error + */ +int vdo_make_packer(struct vdo *vdo, block_count_t bin_count, struct packer **packer_ptr) +{ + struct packer *packer; + block_count_t i; + int result; + + result = UDS_ALLOCATE(1, struct packer, __func__, &packer); + if (result != VDO_SUCCESS) + return result; + + packer->thread_id = vdo->thread_config.packer_thread; + packer->size = bin_count; + INIT_LIST_HEAD(&packer->bins); + vdo_set_admin_state_code(&packer->state, VDO_ADMIN_STATE_NORMAL_OPERATION); + + for (i = 0; i < bin_count; i++) { + result = make_bin(packer); + if (result != VDO_SUCCESS) { + vdo_free_packer(packer); + return result; + } + } + + /* + * The canceled bin can hold up to half the number of user vios. Every canceled vio in the + * bin must have a canceler for which it is waiting, and any canceler will only have + * canceled one lock holder at a time. + */ + result = UDS_ALLOCATE_EXTENDED(struct packer_bin, + MAXIMUM_VDO_USER_VIOS / 2, + struct vio *, __func__, + &packer->canceled_bin); + if (result != VDO_SUCCESS) { + vdo_free_packer(packer); + return result; + } + + result = vdo_make_default_thread(vdo, packer->thread_id); + if (result != VDO_SUCCESS) { + vdo_free_packer(packer); + return result; + } + + *packer_ptr = packer; + return VDO_SUCCESS; +} + +/** + * vdo_free_packer() - Free a block packer. + * @packer: The packer to free. + */ +void vdo_free_packer(struct packer *packer) +{ + struct packer_bin *bin, *tmp; + + if (packer == NULL) + return; + + list_for_each_entry_safe(bin, tmp, &packer->bins, list) { + list_del_init(&bin->list); + UDS_FREE(bin); + } + + UDS_FREE(UDS_FORGET(packer->canceled_bin)); + UDS_FREE(packer); +} + +/** + * get_packer_from_data_vio() - Get the packer from a data_vio. + * @data_vio: The data_vio. + * + * Return: The packer from the VDO to which the data_vio belongs. + */ +static inline struct packer *get_packer_from_data_vio(struct data_vio *data_vio) +{ + return vdo_from_data_vio(data_vio)->packer; +} + +/** + * vdo_get_packer_statistics() - Get the current statistics from the packer. + * @packer: The packer to query. + * + * Return: a copy of the current statistics for the packer. + */ +struct packer_statistics vdo_get_packer_statistics(const struct packer *packer) +{ + const struct packer_statistics *stats = &packer->statistics; + + return (struct packer_statistics) { + .compressed_fragments_written = READ_ONCE(stats->compressed_fragments_written), + .compressed_blocks_written = READ_ONCE(stats->compressed_blocks_written), + .compressed_fragments_in_packer = READ_ONCE(stats->compressed_fragments_in_packer), + }; +} + +/** + * abort_packing() - Abort packing a data_vio. + * @data_vio: The data_vio to abort. + */ +static void abort_packing(struct data_vio *data_vio) +{ + struct packer *packer = get_packer_from_data_vio(data_vio); + + WRITE_ONCE(packer->statistics.compressed_fragments_in_packer, + packer->statistics.compressed_fragments_in_packer - 1); + + write_data_vio(data_vio); +} + +/** + * release_compressed_write_waiter() - Update a data_vio for which a successful compressed write + * has completed and send it on its way. + + * @data_vio: The data_vio to release. + * @allocation: The allocation to which the compressed block was written. + */ +static void +release_compressed_write_waiter(struct data_vio *data_vio, struct allocation *allocation) +{ + data_vio->new_mapped = (struct zoned_pbn) { + .pbn = allocation->pbn, + .zone = allocation->zone, + .state = data_vio->compression.slot + VDO_MAPPING_STATE_COMPRESSED_BASE, + }; + + vdo_share_compressed_write_lock(data_vio, allocation->lock); + update_metadata_for_data_vio_write(data_vio, allocation->lock); +} + +/** + * finish_compressed_write() - Finish a compressed block write. + * @completion: The compressed write completion. + * + * This callback is registered in continue_after_allocation(). + */ +static void finish_compressed_write(struct vdo_completion *completion) +{ + struct data_vio *agent = as_data_vio(completion); + struct data_vio *client, *next; + + assert_data_vio_in_allocated_zone(agent); + + /* + * Process all the non-agent waiters first to ensure that the pbn lock can not be released + * until all of them have had a chance to journal their increfs. + */ + for (client = agent->compression.next_in_batch; client != NULL; client = next) { + next = client->compression.next_in_batch; + release_compressed_write_waiter(client, &agent->allocation); + } + + completion->error_handler = handle_data_vio_error; + release_compressed_write_waiter(agent, &agent->allocation); +} + +static void handle_compressed_write_error(struct vdo_completion *completion) +{ + struct data_vio *agent = as_data_vio(completion); + struct allocation *allocation = &agent->allocation; + struct data_vio *client, *next; + + if (vdo_requeue_completion_if_needed(completion, allocation->zone->thread_id)) + return; + + update_vio_error_stats(as_vio(completion), + "Completing compressed write vio for physical block %llu with error", + (unsigned long long) allocation->pbn); + + for (client = agent->compression.next_in_batch; client != NULL; client = next) { + next = client->compression.next_in_batch; + write_data_vio(client); + } + + /* Now that we've released the batch from the packer, forget the error and continue on. */ + vdo_reset_completion(completion); + completion->error_handler = handle_data_vio_error; + write_data_vio(agent); +} + +/** + * add_to_bin() - Put a data_vio in a specific packer_bin in which it will definitely fit. + * @bin: The bin in which to put the data_vio. + * @data_vio: The data_vio to add. + */ +static void add_to_bin(struct packer_bin *bin, struct data_vio *data_vio) +{ + data_vio->compression.bin = bin; + data_vio->compression.slot = bin->slots_used; + bin->incoming[bin->slots_used++] = data_vio; +} + +/** + * remove_from_bin() - Get the next data_vio whose compression has not been canceled from a bin. + * @packer: The packer. + * @bin: The bin from which to get a data_vio. + * + * Any canceled data_vios will be moved to the canceled bin. + * Return: An uncanceled data_vio from the bin or NULL if there are none. + */ +static struct data_vio *remove_from_bin(struct packer *packer, struct packer_bin *bin) +{ + while (bin->slots_used > 0) { + struct data_vio *data_vio = bin->incoming[--bin->slots_used]; + + if (!advance_data_vio_compression_stage(data_vio).may_not_compress) { + data_vio->compression.bin = NULL; + return data_vio; + } + + add_to_bin(packer->canceled_bin, data_vio); + } + + /* The bin is now empty. */ + bin->free_space = VDO_COMPRESSED_BLOCK_DATA_SIZE; + return NULL; +} + +/** + * initialize_compressed_block() - Initialize a compressed block. + * @block: The compressed block to initialize. + * @size: The size of the agent's fragment. + * + * This method initializes the compressed block in the compressed write agent. Because the + * compressor already put the agent's compressed fragment at the start of the compressed block's + * data field, it needn't be copied. So all we need do is initialize the header and set the size of + * the agent's fragment. + */ +static void initialize_compressed_block(struct compressed_block *block, u16 size) +{ + /* + * Make sure the block layout isn't accidentally changed by changing the length of the + * block header. + */ + STATIC_ASSERT_SIZEOF(struct compressed_block_header, COMPRESSED_BLOCK_1_0_SIZE); + + block->header.version = vdo_pack_version_number(COMPRESSED_BLOCK_1_0); + block->header.sizes[0] = __cpu_to_le16(size); +} + +/** + * pack_fragment() - Pack a data_vio's fragment into the compressed block in which it is already + * known to fit. + * @compression: The agent's compression_state to pack in to. + * @data_vio: The data_vio to pack. + * @offset: The offset into the compressed block at which to pack the fragment. + * @compressed_block: The compressed block which will be written out when batch is fully packed. + * + * Return: The new amount of space used. + */ +static block_size_t __must_check +pack_fragment(struct compression_state *compression, + struct data_vio *data_vio, + block_size_t offset, + slot_number_t slot, + struct compressed_block *block) +{ + struct compression_state *to_pack = &data_vio->compression; + char *fragment = to_pack->block->data; + + to_pack->next_in_batch = compression->next_in_batch; + compression->next_in_batch = data_vio; + to_pack->slot = slot; + block->header.sizes[slot] = __cpu_to_le16(to_pack->size); + memcpy(&block->data[offset], fragment, to_pack->size); + return (offset + to_pack->size); +} + +/** + * compressed_write_end_io() - The bio_end_io for a compressed block write. + * @bio: The bio for the compressed write. + */ +static void compressed_write_end_io(struct bio *bio) +{ + struct data_vio *data_vio = vio_as_data_vio(bio->bi_private); + + vdo_count_completed_bios(bio); + set_data_vio_allocated_zone_callback(data_vio, finish_compressed_write); + continue_data_vio_with_error(data_vio, blk_status_to_errno(bio->bi_status)); +} + +/** + * write_bin() - Write out a bin. + * @packer: The packer. + * @bin: The bin to write. + */ +static void write_bin(struct packer *packer, struct packer_bin *bin) +{ + int result; + block_size_t offset; + slot_number_t slot = 1; + struct compression_state *compression; + struct compressed_block *block; + struct data_vio *agent = remove_from_bin(packer, bin); + struct data_vio *client; + struct packer_statistics *stats; + + if (agent == NULL) + return; + + compression = &agent->compression; + compression->slot = 0; + block = compression->block; + initialize_compressed_block(block, compression->size); + offset = compression->size; + + while ((client = remove_from_bin(packer, bin)) != NULL) + offset = pack_fragment(compression, client, offset, slot++, block); + + /* + * If the batch contains only a single vio, then we save nothing by saving the compressed + * form. Continue processing the single vio in the batch. + */ + if (slot == 1) { + abort_packing(agent); + return; + } + + if (slot < VDO_MAX_COMPRESSION_SLOTS) + /* Clear out the sizes of the unused slots */ + memset(&block->header.sizes[slot], + 0, + (VDO_MAX_COMPRESSION_SLOTS - slot) * sizeof(__le16)); + + agent->vio.completion.error_handler = handle_compressed_write_error; + if (vdo_is_read_only(vdo_from_data_vio(agent))) { + continue_data_vio_with_error(agent, VDO_READ_ONLY); + return; + } + + result = vio_reset_bio(&agent->vio, + (char *) block, + compressed_write_end_io, + REQ_OP_WRITE, + agent->allocation.pbn); + if (result != VDO_SUCCESS) { + continue_data_vio_with_error(agent, result); + return; + } + + /* + * Once the compressed write is submitted, the fragments are no longer in the packer, so + * update stats now. + */ + stats = &packer->statistics; + WRITE_ONCE(stats->compressed_fragments_in_packer, + (stats->compressed_fragments_in_packer - slot)); + WRITE_ONCE(stats->compressed_fragments_written, + (stats->compressed_fragments_written + slot)); + WRITE_ONCE(stats->compressed_blocks_written, stats->compressed_blocks_written + 1); + + submit_data_vio_io(agent); +} + +/** + * add_data_vio_to_packer_bin() - Add a data_vio to a bin's incoming queue + * @packer: The packer. + * @bin: The bin to which to add the data_vio. + * @data_vio: The data_vio to add to the bin's queue. + * + * Adds a data_vio to a bin's incoming queue, handles logical space change, and calls physical + * space processor. + */ +static void add_data_vio_to_packer_bin(struct packer *packer, + struct packer_bin *bin, + struct data_vio *data_vio) +{ + /* If the selected bin doesn't have room, start a new batch to make room. */ + if (bin->free_space < data_vio->compression.size) + write_bin(packer, bin); + + add_to_bin(bin, data_vio); + bin->free_space -= data_vio->compression.size; + + /* If we happen to exactly fill the bin, start a new batch. */ + if ((bin->slots_used == VDO_MAX_COMPRESSION_SLOTS) || + (bin->free_space == 0)) + write_bin(packer, bin); + + /* Now that we've finished changing the free space, restore the sort order. */ + insert_in_sorted_list(packer, bin); +} + +/** + * select_bin() - Select the bin that should be used to pack the compressed data in a data_vio with + * other data_vios. + * @packer: The packer. + * @data_vio: The data_vio. + */ +static struct packer_bin * __must_check +select_bin(struct packer *packer, struct data_vio *data_vio) +{ + /* + * First best fit: select the bin with the least free space that has enough room for the + * compressed data in the data_vio. + */ + struct packer_bin *bin, *fullest_bin; + + list_for_each_entry(bin, &packer->bins, list) + if (bin->free_space >= data_vio->compression.size) + return bin; + + /* + * None of the bins have enough space for the data_vio. We're not allowed to create new + * bins, so we have to overflow one of the existing bins. It's pretty intuitive to select + * the fullest bin, since that "wastes" the least amount of free space in the compressed + * block. But if the space currently used in the fullest bin is smaller than the compressed + * size of the incoming block, it seems wrong to force that bin to write when giving up on + * compressing the incoming data_vio would likewise "waste" the least amount of free space. + */ + fullest_bin = list_first_entry(&packer->bins, struct packer_bin, list); + if (data_vio->compression.size >= + (VDO_COMPRESSED_BLOCK_DATA_SIZE - fullest_bin->free_space)) + return NULL; + + /* + * The fullest bin doesn't have room, but writing it out and starting a new batch with the + * incoming data_vio will increase the packer's free space. + */ + return fullest_bin; +} + +/** + * vdo_attempt_packing() - Attempt to rewrite the data in this data_vio as part of a compressed + * block. + * @data_vio: The data_vio to pack. + */ +void vdo_attempt_packing(struct data_vio *data_vio) +{ + int result; + struct packer_bin *bin; + struct data_vio_compression_status status = get_data_vio_compression_status(data_vio); + struct packer *packer = get_packer_from_data_vio(data_vio); + + assert_on_packer_thread(packer, __func__); + + result = ASSERT((status.stage == DATA_VIO_COMPRESSING), + "attempt to pack data_vio not ready for packing, stage: %u", + status.stage); + if (result != VDO_SUCCESS) + return; + + /* + * Increment whether or not this data_vio will be packed or not since abort_packing() + * always decrements the counter. + */ + WRITE_ONCE(packer->statistics.compressed_fragments_in_packer, + packer->statistics.compressed_fragments_in_packer + 1); + + /* + * If packing of this data_vio is disallowed for administrative reasons, give up before + * making any state changes. + */ + if (!vdo_is_state_normal(&packer->state) || + (data_vio->flush_generation < packer->flush_generation)) { + abort_packing(data_vio); + return; + } + + /* + * The check of may_vio_block_in_packer() here will set the data_vio's compression state to + * VIO_PACKING if the data_vio is allowed to be compressed (if it has already been + * canceled, we'll fall out here). Once the data_vio is in the VIO_PACKING state, it must + * be guaranteed to be put in a bin before any more requests can be processed by the packer + * thread. Otherwise, a canceling data_vio could attempt to remove the canceled data_vio + * from the packer and fail to rendezvous with it (VDO-2809). We must also make sure that + * we will actually bin the data_vio and not give up on it as being larger than the space + * used in the fullest bin. Hence we must call select_bin() before calling + * may_vio_block_in_packer() (VDO-2826). + */ + bin = select_bin(packer, data_vio); + if ((bin == NULL) || + (advance_data_vio_compression_stage(data_vio).stage != DATA_VIO_PACKING)) { + abort_packing(data_vio); + return; + } + + add_data_vio_to_packer_bin(packer, bin, data_vio); +} + +/** + * check_for_drain_complete() - Check whether the packer has drained. + * @packer: The packer. + */ +static void check_for_drain_complete(struct packer *packer) +{ + if (vdo_is_state_draining(&packer->state) && (packer->canceled_bin->slots_used == 0)) + vdo_finish_draining(&packer->state); +} + +/** + * write_all_non_empty_bins() - Write out all non-empty bins on behalf of a flush or suspend. + * @packer: The packer being flushed. + */ +static void write_all_non_empty_bins(struct packer *packer) +{ + struct packer_bin *bin; + + list_for_each_entry(bin, &packer->bins, list) + write_bin(packer, bin); + /* + * We don't need to re-sort the bin here since this loop will make every bin have + * the same amount of free space, so every ordering is sorted. + */ + + check_for_drain_complete(packer); +} + +/** + * vdo_flush_packer() - Request that the packer flush asynchronously. + * @packer: The packer to flush. + * + * All bins with at least two compressed data blocks will be written out, and any solitary pending + * VIOs will be released from the packer. While flushing is in progress, any VIOs submitted to + * vdo_attempt_packing() will be continued immediately without attempting to pack them. + */ +void vdo_flush_packer(struct packer *packer) +{ + assert_on_packer_thread(packer, __func__); + if (vdo_is_state_normal(&packer->state)) + write_all_non_empty_bins(packer); +} + +/** + * vdo_remove_lock_holder_from_packer() - Remove a lock holder from the packer. + * @completion: The data_vio which needs a lock held by a data_vio in the packer. The data_vio's + * compression.lock_holder field will point to the data_vio to remove. + */ +void vdo_remove_lock_holder_from_packer(struct vdo_completion *completion) +{ + struct data_vio *data_vio = as_data_vio(completion); + struct packer *packer = get_packer_from_data_vio(data_vio); + struct data_vio *lock_holder; + struct packer_bin *bin; + slot_number_t slot; + + assert_data_vio_in_packer_zone(data_vio); + + lock_holder = UDS_FORGET(data_vio->compression.lock_holder); + bin = lock_holder->compression.bin; + ASSERT_LOG_ONLY((bin != NULL), "data_vio in packer has a bin"); + + slot = lock_holder->compression.slot; + bin->slots_used--; + if (slot < bin->slots_used) { + bin->incoming[slot] = bin->incoming[bin->slots_used]; + bin->incoming[slot]->compression.slot = slot; + } + + lock_holder->compression.bin = NULL; + lock_holder->compression.slot = 0; + + if (bin != packer->canceled_bin) { + bin->free_space += lock_holder->compression.size; + insert_in_sorted_list(packer, bin); + } + + abort_packing(lock_holder); + check_for_drain_complete(packer); +} + +/** + * vdo_increment_packer_flush_generation() - Increment the flush generation in the packer. + * @packer: The packer. + * + * This will also cause the packer to flush so that any VIOs from previous generations will exit + * the packer. + */ +void vdo_increment_packer_flush_generation(struct packer *packer) +{ + assert_on_packer_thread(packer, __func__); + packer->flush_generation++; + vdo_flush_packer(packer); +} + +/** + * initiate_drain() - Initiate a drain. + * + * Implements vdo_admin_initiator. + */ +static void initiate_drain(struct admin_state *state) +{ + struct packer *packer = container_of(state, struct packer, state); + + write_all_non_empty_bins(packer); +} + +/** + * vdo_drain_packer() - Drain the packer by preventing any more VIOs from entering the packer and + * then flushing. + * @packer: The packer to drain. + * @completion: The completion to finish when the packer has drained. + */ +void vdo_drain_packer(struct packer *packer, struct vdo_completion *completion) +{ + assert_on_packer_thread(packer, __func__); + vdo_start_draining(&packer->state, VDO_ADMIN_STATE_SUSPENDING, completion, initiate_drain); +} + +/** + * vdo_resume_packer() - Resume a packer which has been suspended. + * @packer: The packer to resume. + * @parent: The completion to finish when the packer has resumed. + */ +void vdo_resume_packer(struct packer *packer, struct vdo_completion *parent) +{ + assert_on_packer_thread(packer, __func__); + vdo_continue_completion(parent, vdo_resume_if_quiescent(&packer->state)); +} + +static void dump_packer_bin(const struct packer_bin *bin, bool canceled) +{ + if (bin->slots_used == 0) + /* Don't dump empty bins. */ + return; + + uds_log_info(" %sBin slots_used=%u free_space=%zu", + (canceled ? "Canceled" : ""), bin->slots_used, + bin->free_space); + + /* + * FIXME: dump vios in bin->incoming? The vios should have been dumped from the vio pool. + * Maybe just dump their addresses so it's clear they're here? + */ +} + +/** + * vdo_dump_packer() - Dump the packer. + * @packer: The packer. + * + * Context: dumps in a thread-unsafe fashion. + */ +void vdo_dump_packer(const struct packer *packer) +{ + struct packer_bin *bin; + + uds_log_info("packer"); + uds_log_info(" flushGeneration=%llu state %s packer_bin_count=%llu", + (unsigned long long) packer->flush_generation, + vdo_get_admin_state_code(&packer->state)->name, + (unsigned long long) packer->size); + + list_for_each_entry(bin, &packer->bins, list) + dump_packer_bin(bin, false); + + dump_packer_bin(packer->canceled_bin, true); +} diff --git a/drivers/md/dm-vdo/packer.h b/drivers/md/dm-vdo/packer.h new file mode 100644 index 00000000000..8eed435cf9f --- /dev/null +++ b/drivers/md/dm-vdo/packer.h @@ -0,0 +1,123 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright Red Hat + */ + +#ifndef VDO_PACKER_H +#define VDO_PACKER_H + +#include + +#include "admin-state.h" +#include "constants.h" +#include "encodings.h" +#include "statistics.h" +#include "types.h" +#include "wait-queue.h" + +enum { + DEFAULT_PACKER_BINS = 16, +}; + +/* The header of a compressed block. */ +struct compressed_block_header { + /* Unsigned 32-bit major and minor versions, little-endian */ + struct packed_version_number version; + + /* List of unsigned 16-bit compressed block sizes, little-endian */ + __le16 sizes[VDO_MAX_COMPRESSION_SLOTS]; +} __packed; + +enum { + VDO_COMPRESSED_BLOCK_DATA_SIZE = VDO_BLOCK_SIZE - sizeof(struct compressed_block_header), + + /* + * A compressed block is only written if we can pack at least two fragments into it, so a + * fragment which fills the entire data portion of a compressed block is too big. + */ + VDO_MAX_COMPRESSED_FRAGMENT_SIZE = VDO_COMPRESSED_BLOCK_DATA_SIZE - 1, +}; + +/* * The compressed block overlay. */ +struct compressed_block { + struct compressed_block_header header; + char data[VDO_COMPRESSED_BLOCK_DATA_SIZE]; +} __packed; + +/* + * Each packer_bin holds an incomplete batch of data_vios that only partially fill a compressed + * block. The bins are kept in a ring sorted by the amount of unused space so the first bin with + * enough space to hold a newly-compressed data_vio can easily be found. When the bin fills up or + * is flushed, the first uncanceled data_vio in the bin is selected to be the agent for that bin. + * Upon entering the packer, each data_vio already has its compressed data in the first slot of the + * data_vio's compressed_block (overlaid on the data_vio's scratch_block). So the agent's fragment + * is already in place. The fragments for the other uncanceled data_vios in the bin are packed into + * the agent's compressed block. The agent then writes out the compressed block. If the write is + * successful, the agent shares its pbn lock which each of the other data_vios in its compressed + * block and sends each on its way. Finally the agent itself continues on the write path as before. + * + * There is one special bin which is used to hold data_vios which have been canceled and removed + * from their bin by the packer. These data_vios need to wait for the canceller to rendezvous with + * them (VDO-2809) and so they sit in this special bin. + */ +struct packer_bin { + /* List links for packer.packer_bins */ + struct list_head list; + /* The number of items in the bin */ + slot_number_t slots_used; + /* The number of compressed block bytes remaining in the current batch */ + size_t free_space; + /* The current partial batch of data_vios, waiting for more */ + struct data_vio *incoming[]; +}; + +struct packer { + /* The ID of the packer's callback thread */ + thread_id_t thread_id; + /* The number of bins */ + block_count_t size; + /* A list of all packer_bins, kept sorted by free_space */ + struct list_head bins; + /* + * A bin to hold data_vios which were canceled out of the packer and are waiting to + * rendezvous with the canceling data_vio. + */ + struct packer_bin *canceled_bin; + + /* The current flush generation */ + sequence_number_t flush_generation; + + /* The administrative state of the packer */ + struct admin_state state; + + /* Statistics are only updated on the packer thread, but are accessed from other threads */ + struct packer_statistics statistics; +}; + +int vdo_get_compressed_block_fragment(enum block_mapping_state mapping_state, + struct compressed_block *block, + u16 *fragment_offset, + u16 *fragment_size); + +int __must_check +vdo_make_packer(struct vdo *vdo, block_count_t bin_count, struct packer **packer_ptr); + +void vdo_free_packer(struct packer *packer); + +struct packer_statistics __must_check vdo_get_packer_statistics(const struct packer *packer); + +void vdo_attempt_packing(struct data_vio *data_vio); + +void vdo_flush_packer(struct packer *packer); + +void vdo_remove_lock_holder_from_packer(struct vdo_completion *completion); + +void vdo_increment_packer_flush_generation(struct packer *packer); + +void vdo_drain_packer(struct packer *packer, struct vdo_completion *completion); + +void vdo_resume_packer(struct packer *packer, struct vdo_completion *parent); + +void vdo_dump_packer(const struct packer *packer); + +#endif /* VDO_PACKER_H */