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path: root/drivers/lightnvm/pblk-map.c
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2019-05-06lightnvm: pblk: ensure that erase is chunk alignedIgor Konopko
The sector bits in the erase command may be uninitialized are uninitialized, causing the erase LBA to be unaligned to the chunk size. This is unexpected situation, since erase shall always be chunk aligned based on OCSSD the 2.0 specification. Signed-off-by: Igor Konopko <igor.j.konopko@intel.com> Reviewed-by: Javier González <javier@javigon.com> Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-02-11lightnvm: pblk: fix race condition on GCHeiner Litz
This patch fixes a race condition where a write is mapped to the last sectors of a line. The write is synced to the device but the L2P is not updated yet. When the line is garbage collected before the L2P update is performed, the sectors are ignored by the GC logic and the line is freed before all sectors are moved. When the L2P is finally updated, it contains a mapping to a freed line, subsequent reads of the corresponding LBAs fail. This patch introduces a per line counter specifying the number of sectors that are synced to the device but have not been updated in the L2P. Lines with a counter of greater than zero will not be selected for GC. Signed-off-by: Heiner Litz <hlitz@ucsc.edu> Reviewed-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-11lightnvm: pblk: support packed metadataIgor Konopko
pblk performs recovery of open lines by storing the LBA in the per LBA metadata field. Recovery therefore only works for drives that has this field. This patch adds support for packed metadata, which store l2p mapping for open lines in last sector of every write unit and enables drives without per IO metadata to recover open lines. After this patch, drives with OOB size <16B will use packed metadata and metadata size larger than16B will continue to use the device per IO metadata. Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-11lightnvm: pblk: add helpers for OOB metadataIgor Konopko
pblk currently assumes that size of OOB metadata on drive is always equal to size of pblk_sec_meta struct. This commit add helpers which will allow to handle different sizes of OOB metadata on drive in the future. After this patch only OOB metadata equal to 16 bytes is supported. Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Igor Konopko <igor.j.konopko@intel.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-12-11lightnvm: pblk: stop writes gracefully when running out of linesHans Holmberg
If mapping fails (i.e. when running out of lines), handle the error and stop writing. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-09lightnvm: pblk: add SPDX license tagJavier González
Add GLP-2.0 SPDX license tag to all pblk files Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-09lightnvm: pblk: remove debug from pblk_[down/up]_pageMatias Bjørling
Remove the debug only iteration within __pblk_down_page, which then allows us to reduce the number of arguments down to pblk and the parallel unit from the functions that calls it. Simplifying the callers logic considerably. Also, rename the functions pblk_[down/up]_page to pblk_[down/up]_chunk, to communicate that it manages the write pointer of the chunk. Note that it also protects the parallel unit such that at most one chunk is active per parallel unit. Signed-off-by: Matias Bjørling <mb@lightnvm.io> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-10-09lightnvm: introduce nvm_rq_to_ppa_listHans Holmberg
There is a number of places in the lightnvm subsystem where the user iterates over the ppa list. Before iterating, the user must know if it is a single or multiple LBAs due to vector commands using either the nvm_rq ->ppa_addr or ->ppa_list fields on command submission, which leads to open-coding the if/else statement. Instead of having multiple if/else's, move it into a function that can be called by its users. A nice side effect of this cleanup is that this patch fixes up a bunch of cases where we don't consider the single-ppa case in pblk. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-01lightnvm: pblk: fail gracefully on line alloc. failureJavier González
In the event of a line failing to allocate, fail gracefully and stop the pipeline to avoid more write failing in the same place. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-29lightnvm: add support for 2.0 address formatJavier González
Add support for 2.0 address format. Also, align address bits for 1.2 and 2.0 to be able to operate on channel and luns without requiring a format conversion. Use a generic address format for this purpose. Also, convert the generic operations to the generic format in pblk. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-03-29lightnvm: pblk: export write amplification counters to sysfsHans Holmberg
In a SSD, write amplification, WA, is defined as the average number of page writes per user page write. Write amplification negatively affects write performance and decreases the lifetime of the disk, so it's a useful metric to add to sysfs. In plkb's case, the number of writes per user sector is the sum of: (1) number of user writes (2) number of sectors written by the garbage collector (3) number of sectors padded (i.e. due to syncs) This patch adds persistent counters for 1-3 and two sysfs attributes to export these along with WA calculated with five decimals: write_amp_mileage: the accumulated write amplification stats for the lifetime of the pblk instance write_amp_trip: resetable stats to facilitate delta measurements, values reset at creation and if 0 is written to the attribute. 64-bit counters are used as a 32 bit counter would wrap around already after about 17 TB worth of user data. It will take a long long time before the 64 bit sector counters wrap around. The counters are stored after the bad block bitmap in the first emeta sector of each written line. There is plenty of space in the first emeta sector, so we don't need to bump the major version of the line data format. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-01-05lightnvm: use internal pblk methodsMatias Bjørling
Now that rrpc has been removed, the only users of the ppa helpers is pblk. However, pblk already defines similar functions. Switch pblk to use the internal ones, and remove the generic ppa helpers. Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13lightnvm: pblk: correct valid lba count calculationHans Holmberg
During garbage collect, lbas being written can end up being invalidated. Make sure that this is reflected in the valid lba count. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13lightnvm: pblk: enable 1 LUN configurationJavier González
Metadata I/Os are scheduled to minimize their impact on user data I/Os. When there are enough LUNs instantiated (i.e., enough bandwidth), it is easy to interleave metadata and data one after the other so that metadata I/Os are the ones being blocked and not vice-versa. We do this by calculating the distance between the I/Os in terms of the LUNs that are not in used, and selecting a free LUN that satisfies a the simple heuristic that metadata is scheduled behind. The per-LUN semaphores guarantee consistency. This works fine on >1 LUN configuration. However, when a single LUN is instantiated, this design leads to a deadlock, where metadata waits to be scheduled on a free LUN. This patch implements the 1 LUN case by simply scheduling the metadada I/O after the data I/O. In the process, we refactor the way a line is replaced to ensure that metadata writes are submitted after data writes in order to guarantee block sequentiality. Note that, since there is only one LUN, both I/Os will block each other by design. However, such configuration only pursues tight read latencies, not write bandwidth. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-30lightnvm: pblk: fix bad le64 assignationsJavier González
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>
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: 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: 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: spare double cpu_to_le64 calc.Javier González
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>
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: 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>