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path: root/drivers/lightnvm/pblk-cache.c
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2021-08-14remove the lightnvm subsystemChristoph Hellwig
Lightnvm supports the OCSSD 1.x and 2.0 specs which were early attempts to produce Open Channel SSDs and never made it into the NVMe spec proper. They have since been superceeded by NVMe enhancements such as ZNS support. Remove the support per the deprecation schedule. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210812132308.38486-1-hch@lst.de Reviewed-by: Matias Bjørling <mb@lightnvm.io> Reviewed-by: Javier González <javier@javigon.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-05-27lightnvm/pblk: use bio_{start,end}_io_acctChristoph Hellwig
Switch rsxx to use the nicer bio accounting helpers. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2019-05-06lightnvm: pblk: IO path reorganizationIgor Konopko
This patch is made in order to prepare read path for new approach to partial read handling, which is simpler in compare with previous one. The most important change is to move the handling of completed and failed bio from the pblk_make_rq() to particular read and write functions. This is needed, since after partial read path changes, sometimes completed/failed bio will be different from original one, so we cannot do this any longer in pblk_make_rq(). Other changes are small read path refactor in order to reduce the size of the following patch with partial read changes. Generally the goal of this patch is not to change the functionality, but just to prepare the code for the following changes. Signed-off-by: Igor Konopko <igor.j.konopko@intel.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>
2018-07-18block: Add and use op_stat_group() for indexing disk_stat fields.Michael Callahan
Add and use a new op_stat_group() function for indexing partition stat fields rather than indexing them by rq_data_dir() or bio_data_dir(). This function works similarly to op_is_sync() in that it takes the request::cmd_flags or bio::bi_opf flags and determines which stats should et updated. In addition, the second parameter to generic_start_io_acct() and generic_end_io_acct() is now a REQ_OP rather than simply a read or write bit and it uses op_stat_group() on the parameter to determine the stat group. Note that the partition in_flight counts are not part of the per-cpu statistics and as such are not indexed via this function. It's now indexed by op_is_write(). tj: Refreshed on top of v4.17. Updated to pass around REQ_OP. Signed-off-by: Michael Callahan <michaelcallahan@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Joshua Morris <josh.h.morris@us.ibm.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Matias Bjorling <mb@lightnvm.io> Cc: Kent Overstreet <kent.overstreet@gmail.com> Cc: Alasdair Kergon <agk@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-07-13lightnvm: move NVM_DEBUG to pblkMatias Bjørling
There is no users of CONFIG_NVM_DEBUG in the LightNVM subsystem. All users are in pblk. Rename NVM_DEBUG to NVM_PBLK_DEBUG and enable only for pblk. Also fix up the CONFIG_NVM_PBLK entry to follow the code style for Kconfig files. Signed-off-by: Matias Bjørling <mb@lightnvm.io> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2018-06-01lightnvm: pblk: kick writer on new flush pointsHans Holmberg
Unless we kick the writer directly when setting a new flush point, the user risks having to wait for up to one second (the default timeout for the write thread to be kicked) for the IO to complete. 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>
2018-03-29lightnvm: 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: pblk: add iostat supportJavier González
Since pblk registers its own block device, the iostat accounting is not automatically done for us. Therefore, add the necessary accounting logic to satisfy the iostat interface. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13lightnvm: pblk: simplify path on REQ_PREFLUSHJavier González
On REQ_PREFLUSH, directly tag the I/O context flags to signal a flush in the write to cache path, instead of finding the correct entry context and imposing a memory barrier. This simplifies the code and might potentially prevent race conditions when adding functionality to the write path. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-10-13lightnvm: pblk: simplify data validity check on GCJavier González
When a line is selected for recycling by the garbage collector (GC), the line state changes and the invalid bitmap is frozen, preventing invalidations from happening. Throughout the GC, the L2P map is checked to verify that not data being recycled has been updated. The last check is done before the new map is being stored on the L2P table. Though this algorithm works, it requires a number of corner cases to be checked each time the L2P table is being updated. This complicates readability and is error prone in case that the recycling algorithm is modified. Instead, this patch makes the invalid bitmap accessible even when the line is being recycled. When recycled data is being remapped, it is enough to check the invalid bitmap for the line before updating the L2P table. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2017-06-26lightnvm: 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>
2017-04-16lightnvm: 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>