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path: root/drivers/lightnvm/pblk-init.c
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2017-06-30lightnvm: pblk: add initialization checkJavier González
Add a sanity check to the pblk initialization sequence in order to ensure that enough LUNs have been allocated to store the line metadata. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-30lightnvm: pblk: remove target using async. I/OsJavier González
When removing a pblk instance, pad the current line using asynchronous I/O. This reduces the removal time from ~1 minute in the worst case to a couple of seconds. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-30lightnvm: pblk: fix double-free on pblk initJavier González
Prevent pblk->lines being double freed in case of an error during pblk initialization. Fixes: dd2a43437337: "lightnvm: pblk: sched. metadata on write thread" Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: fail gracefully on irrec. errorJavier González
Due to user writes being decoupled from media writes because of the need of an intermediate write buffer, irrecoverable media write errors lead to pblk stalling; user writes fill up the buffer and end up in an infinite retry loop. In order to let user writes fail gracefully, it is necessary for pblk to keep track of its own internal state and prevent further writes from being placed into the write buffer. This patch implements a state machine to keep track of internal errors and, in case of failure, fail further user writes in an standard way. Depending on the type of error, pblk will do its best to persist buffered writes (which are already acknowledged) and close down on a graceful manner. This way, data might be recovered by re-instantiating pblk. Such state machine paves out the way for a state-based FTL log. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: set mempool and workqueue params.Javier González
Make constants to define sizes for internal mempools and workqueues. In this process, adjust the values to be more meaningful given the internal constrains of the FTL. In order to do this for workqueues, separate the current auxiliary workqueue into two dedicated workqueues to manage lines being closed and bad blocks. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: decouple bad block from line allocJavier González
Decouple bad block discovery from line allocation logic. This allows to return meaningful error codes in case of bad block discovery failure. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: simplify meta. memory allocationJavier González
smeta size will always be suitable for a kmalloc allocation. Simplify the code and leave the vmalloc fallback only for emeta, where the pblk configuration has an impact. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: delete redundant buffer pointerJavier González
After refactoring the metadata path, the backpointer controlling synced I/Os in a line becomes unnecessary; metadata is scheduled on the write thread, thus we know when the end of the line is reached and act on it directly. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: sched. metadata on write threadJavier González
At the moment, line metadata is persisted on a separate work queue, that is kicked each time that a line is closed. The assumption when designing this was that freeing the write thread from creating a new write request was better than the potential impact of writes colliding on the media (user I/O and metadata I/O). Experimentation has proven that this assumption is wrong; collision can cause up to 25% of bandwidth and introduce long tail latencies on the write thread, which potentially cause user write threads to spend more time spinning to get a free entry on the write buffer. This patch moves the metadata logic to the write thread. When a line is closed, remaining metadata is written in memory and is placed on a metadata queue. The write thread then takes the metadata corresponding to the previous line, creates the write request and schedules it to minimize collisions on the media. Using this approach, we see that we can saturate the media's bandwidth, which helps reducing both write latencies and the spinning time for user writer threads. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: rename read request poolJavier González
Read requests allocate some extra memory to store its per I/O context. Instead of requiring yet another memory pool for other type of requests, generalize this context allocation (and change naming accordingly). Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: generalize erase pathJavier González
Erase I/Os are scheduled with the following goals in mind: (i) minimize LUNs collisions with write I/Os, and (ii) even out the price of erasing on every write, instead of putting all the burden on when garbage collection runs. This works well on the current design, but is specific to the default mapping algorithm. This patch generalizes the erase path so that other mapping algorithms can select an arbitrary line to be erased instead. It also gets rid of the erase semaphore since it creates jittering for user writes. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: expose max sec per write on sysfsJavier González
Allow to configure the number of maximum sectors per write command through sysfs. This makes it easier to tune write command sizes for different controller configurations. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: pblk: add debug stat for read cache hitsJavier González
Add a new debug counter to measure cache hits on the read path Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-18lightnvm/pblk-read: use bio_clone_fast()NeilBrown
pblk_submit_read() uses bio_clone_bioset() but doesn't change the io_vec, so bio_clone_fast() is a better choice. It also uses fs_bio_set which is intended for filesystems. Using it in a device driver can deadlock. So allocate a new bioset, and and use bio_clone_fast(). Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Javier González <javier@cnexlabs.com> Tested-by: Javier González <javier@cnexlabs.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-18blk: remove bio_set arg from blk_queue_split()NeilBrown
blk_queue_split() is always called with the last arg being q->bio_split, where 'q' is the first arg. Also blk_queue_split() sometimes uses the passed-in 'bs' and sometimes uses q->bio_split. This is inconsistent and unnecessary. Remove the last arg and always use q->bio_split inside blk_queue_split() Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Ming Lei <ming.lei@redhat.com> Credit-to: Javier González <jg@lightnvm.io> (Noticed that lightnvm was missed) Reviewed-by: Javier González <javier@cnexlabs.com> Tested-by: Javier González <javier@cnexlabs.com> Signed-off-by: NeilBrown <neilb@suse.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-04-25lightnvm: fix possible memory leak in pblk_bb_discovery()Wei Yongjun
'blks' is malloced in pblk_bb_discovery() and should be freed before leaving from the nvm_get_tgt_bb_tbl() error handling cases, otherwise it will cause memory leak. Also skip assign blks to rlun->bb_list when error. Fixes: a4bd217b4326 ("lightnvm: physical block device (pblk) target") Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-23lightnvm: pblk: fix erase counters on error failJavier González
When block erases fail, these blocks are marked bad. The number of valid blocks in the line was not updated, which could cause an infinite loop on the erase path. Fix this atomic counter and, in order to avoid taking an irq lock on the interrupt context, make the erase counters atomic too. Also, in the case that a significant number of blocks become bad in a line, the result is the double shared metadata buffer (emeta) to stop the pipeline until all metadata is flushed to the media. Increase the number of metadata lines from 2 to 4 to avoid this case. Fixes: a4bd217b4326 "lightnvm: physical block device (pblk) target" Signed-off-by: Javier González <javier@cnexlabs.com> Reviewed-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16lightnvm: fix some error code in pblk-init.cDan Carpenter
There were a bunch of places in pblk_lines_init() where we didn't set an error code. And in pblk_writer_init() we accidentally return 1 instead of a correct error code, which would result in a Oops later. Fixes: 11a5d6fdf919 ("lightnvm: physical block device (pblk) target") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-04-16lightnvm: physical block device (pblk) targetJavier González
This patch introduces pblk, a host-side translation layer for Open-Channel SSDs to expose them like block devices. The translation layer allows data placement decisions, and I/O scheduling to be managed by the host, enabling users to optimize the SSD for their specific workloads. An open-channel SSD has a set of LUNs (parallel units) and a collection of blocks. Each block can be read in any order, but writes must be sequential. Writes may also fail, and if a block requires it, must also be reset before new writes can be applied. To manage the constraints, pblk maintains a logical to physical address (L2P) table, write cache, garbage collection logic, recovery scheme, and logic to rate-limit user I/Os versus garbage collection I/Os. The L2P table is fully-associative and manages sectors at a 4KB granularity. Pblk stores the L2P table in two places, in the out-of-band area of the media and on the last page of a line. In the cause of a power failure, pblk will perform a scan to recover the L2P table. The user data is organized into lines. A line is data striped across blocks and LUNs. The lines enable the host to reduce the amount of metadata to maintain besides the user data and makes it easier to implement RAID or erasure coding in the future. pblk implements multi-tenant support and can be instantiated multiple times on the same drive. Each instance owns a portion of the SSD - both regarding I/O bandwidth and capacity - providing I/O isolation for each case. Finally, pblk also exposes a sysfs interface that allows user-space to peek into the internals of pblk. The interface is available at /dev/block/*/pblk/ where * is the block device name exposed. This work also contains contributions from: Matias Bjørling <matias@cnexlabs.com> Simon A. F. Lund <slund@cnexlabs.com> Young Tack Jin <youngtack.jin@gmail.com> Huaicheng Li <huaicheng@cs.uchicago.edu> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@fb.com>