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path: root/drivers/lightnvm/pblk-recovery.c
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* lightnvm: pblk: control I/O flow also on tear downJavier González2017-07-071-10/+21
| | | | | | | | | When removing a pblk instance, control the write I/O flow to the controller as we do in the fast 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>
* lightnvm: pblk: remove target using async. I/OsJavier González2017-06-301-71/+92
| | | | | | | | | | 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>
* lightnvm: pblk: use right metadata buffer for recoveryJavier González2017-06-301-3/+3
| | | | | | | | | | Fix bad metadata buffer assignations introduced when refactoring the medatada write path. Fixes: dd2a43437337 lightnvm: pblk: sched. metadata on write thread Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: fix bad le64 assignationsJavier González2017-06-301-1/+1
| | | | | | | | | Use the right types and conversions on le64 variables. Reported by sparse. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: fail gracefully on irrec. errorJavier González2017-06-261-9/+22
| | | | | | | | | | | | | | | | | | | | | | 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>
* lightnvm: pblk: issue multiplane reads if possibleJavier González2017-06-261-3/+15
| | | | | | | | | | If a read request is sequential and its size aligns with a multi-plane page size, use the multi-plane hint to process the I/O in parallel in the controller. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <matias@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: delete redundant buffer pointerJavier González2017-06-261-2/+0
| | | | | | | | | | | 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>
* lightnvm: pblk: sched. metadata on write threadJavier González2017-06-261-32/+35
| | | | | | | | | | | | | | | | | | | | | | | | 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>
* lightnvm: pblk: rename read request poolJavier González2017-06-261-4/+4
| | | | | | | | | | 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>
* lightnvm: pblk: spare double cpu_to_le64 calc.Javier González2017-06-261-2/+2
| | | | | | | | Spare a double calculation on the fast write 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>
* lightnvm: fix some WARN() messagesDan Carpenter2017-04-161-1/+1
| | | | | | | | | WARN_ON() takes a condition, not an error message. I slightly tweaked some conditions so hopefully it's more clear. 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>
* lightnvm: physical block device (pblk) targetJavier González2017-04-161-0/+998
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>