summaryrefslogtreecommitdiffstats
path: root/drivers/lightnvm/pblk.h
Commit message (Collapse)AuthorAgeFilesLines
* lightnvm: pblk: refactor bad block identificationJavier González2018-03-291-6/+0
| | | | | | | | | | In preparation for the OCSSD 2.0 spec. bad block identification, refactor the current code to generalize bad block get/set functions and structures. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: add padding distribution sysfs attributeHans Holmberg2018-03-291-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | When pblk receives a sync, all data up to that point in the write buffer must be comitted to persistent storage, and as flash memory comes with a minimal write size there is a significant cost involved both in terms of time for completing the sync and in terms of write amplification padded sectors for filling up to the minimal write size. In order to get a better understanding of the costs involved for syncs, Add a sysfs attribute to pblk: padded_dist, showing a normalized distribution of sectors padded. In order to facilitate measurements of specific workloads during the lifetime of the pblk instance, the distribution can be reset by writing 0 to the attribute. Do this by introducing counters for each possible padding: {0..(minimal write size - 1)} and calculate the normalized distribution when showing the attribute. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Rearranged total_buckets statement in pblk_sysfs_get_padding_dist Signed-off-by: Matias Bjørling <mb@lightnvm.io> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: export write amplification counters to sysfsHans Holmberg2018-03-291-7/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* lightnvm: pblk: check data lines version on recoveryHans Holmberg2018-03-291-2/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As a preparation for future bumps of data line persistent storage versions, we need to start checking the emeta line version during recovery. Also slit up the current emeta/smeta version into two bytes (major,minor). Recovering lines with the same major number as the current pblk data line version must succeed. This means that any changes in the persistent format must be: (1) Backward compatible: if we switch back to and older kernel, recovery of lines stored with major == current_major and minor > current_minor must succeed. (2) Forward compatible: switching to a newer kernel, recovery of lines stored with major=current_major and minor < minor must handle the data format differences gracefully(i.e. initialize new data structures to default values). If we detect lines that have a different major number than the current we must abort recovery. The user must manually migrate the data in this case. Previously the version stored in the emeta header was copied from smeta, which has version 1, so we need to set the minor version to 1. 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>
* lightnvm: pblk: refactor pblk_ppa_comp functionMatias Bjørling2018-01-051-4/+1
| | | | | | | Shorten function to simply return the value of the if statement. Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: add iostat supportJavier González2018-01-051-0/+1
| | | | | | | | | | 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>
* lightnvm: pblk: do not log recovery read errorsJavier González2018-01-051-0/+1
| | | | | | | | | | | | | | On scan recovery, reads can fail. This happens because the first page for each line is read in order to determined if the line has been used (and thus needs to be recovered), or not. This can lead to "empty page" read errors. Since these errors are normal, do not log them, as they are confusing when reviewing the logs. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: set target over-provision on create ioctlJavier González2018-01-051-0/+2
| | | | | | | | | | | | | Allow to set the over-provision percentage on target creation. In case that the value is not provided, fall back to the default value set by the target. In pblk, set the default OP to 11% of the total size of the device Signed-off-by: Javier González <javier@cnexlabs.com> 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>
* lightnvm: pblk: use exact free block counter in RLJavier González2018-01-051-6/+9
| | | | | | | | | | | | | | Until now, pblk's rate-limiter has used a heuristic to reserve space for GC I/O given that the over-provision area was fixed. In preparation for allowing to define the over-provision area on target creation, define a dedicated free_block counter in the rate-limiter to track the number of blocks being used for user data. Signed-off-by: Javier González <javier@cnexlabs.com> 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>
* lightnvm: pblk: rename sync_point to flush_pointHans Holmberg2018-01-051-3/+3
| | | | | | | | | | | Sync point is a really confusing name for keeping track of the last entry that needs to be flushed so change the name to to flush_point instead. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: refactor emeta consistency checkHans Holmberg2018-01-051-1/+1
| | | | | | | | | | | | | | Currently pblk_recov_get_lba list does two separate things: it checks the consistency of the emeta and extracts the lba list. This patch separates the consistency check to make the code easier to read and to prepare for version checks of the line emeta persistent data format version. Signed-off-by: Hans Holmberg <hans.holmberg@cnexlabs.com> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: remove pblk_for_each_lun helperJavier González2018-01-051-4/+0
| | | | | | Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: compress and reorder helper functionsJavier González2018-01-051-73/+46
| | | | | | | | | | Through time, we have generated some redundant helper functions. Refactor them to eliminate redundant and unnecessary code. Also, reorder them to improve readability Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: make geometry structures 2.0 readyMatias Bjørling2018-01-051-4/+4
| | | | | | | | | | Prepare for the 2.0 revision by adapting the geometry structures to coexist with the 1.2 revision. Signed-off-by: Matias Bjørling <m@bjorling.me> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: Convert timers to use timer_setup()Kees Cook2017-11-211-1/+1
| | | | | | | | | | In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new timer_setup() and from_timer() to pass the timer pointer explicitly. Cc: Matias Bjorling <mb@lightnvm.io> Cc: linux-block@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org>
* lightnvm: pblk: remove leftover testing functionJavier González2017-10-241-5/+0
| | | | | | | | | A previous patch inadvertently left an unused test function in the header, kill it. Fixes: 8bd400204bd5 ("lightnvm: pblk: cleanup unused and static functions") Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: implement generic path for sync I/OJavier González2017-10-131-3/+39
| | | | | | | | | | Implement a generic path for sending sync I/O on LightNVM. This allows to reuse the standard synchronous path trough blk_execute_rq(), instead of implementing a wait_for_completion on the target side (e.g., pblk). Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: cleanup unused and static functionsJavier González2017-10-131-9/+5
| | | | | | | | Cleanup up unused and static functions across the whole codebase. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: gc all lines in the pipeline before exitHans Holmberg2017-10-131-1/+4
| | | | | | | | | | | | | | | | | Finish garbage collect of the lines that are in the gc pipeline before exiting. Ensure that all lines already in in the pipeline goes through, from read to write. Do this by keeping track of how many lines are in the pipeline and waiting for that number to reach zero before exiting the gc reader task. Since we're adding a new gc line counter, change the name of inflight_gc to read_inflight_gc to make the distinction clear. 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>
* lightnvm: pblk: start gc if needed during initHans Holmberg2017-10-131-0/+2
| | | | | | | | | | | | Start GC if needed, directly after init, as we might need to garbage collect in order to make room for user writes. Create a helper function that allows to kick GC without exposing the internals of the GC/rate-limiter interaction. 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>
* lightnvm: pblk: free full lines during recoveryHans Holmberg2017-10-131-0/+1
| | | | | | | | | | | | | | When rebuilding the L2P table, any full lines (lines without any valid sectors) will be identified. If these lines are not freed, we risk not being able to allocate the first data line. This patch refactors the part of GC that frees empty lines into a separate function and adds a call to this after the L2P table has been rebuilt. 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>
* lightnvm: pblk: enable 1 LUN configurationJavier González2017-10-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* lightnvm: pblk: guarantee line integrity on readsJavier González2017-10-131-0/+2
| | | | | | | | | | | | | | | When a line is recycled during garbage collection, reads can still be issued to the line. If the line is freed in the middle of this process, data corruption might occur. This patch guarantees that lines are not freed in the middle of reads that target them (lines). Specifically, we use the existing line reference to decide when a line is eligible for being freed after the recycle process. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: check lba sanity on read pathJavier González2017-10-131-1/+3
| | | | | | | | | | | | | | | | | As part of pblk's recovery scheme, we store the lba mapped to each physical sector on the device's out-of-bound (OOB) area. On the read path, we can use this information to validate that the data being delivered to the upper layers corresponds to the lba being requested. The cost of this check is an extra copy on the DMA region on the device and an extra comparison in the host, given that (i) the OOB area is being read together with the data in the media, and (ii) the DMA region allocated for the ppa list can be reused for the metadata stored on the OOB area. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: refactor rqd alloc/freeJavier González2017-10-131-2/+2
| | | | | | | | | Refactor the rqd allocation and free functions so that all I/O types can use these helper functions. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: improve naming for internal req.Javier González2017-10-131-3/+8
| | | | | | | | | | | | | | | | Each request type sent to the LightNVM subsystem requires different metadata. Until now, we have tailored this metadata based on write, read and erase commands. However, pblk uses different metadata for internal writes that do not hit the write buffer. Instead of abusing the metadata for reads, create a new request type - internal write to improve code readability. In the process, create internal values for each I/O type instead of abusing the READ/WRITE macros, as suggested by Christoph. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: allocate bio size more accuratelyJavier González2017-10-131-2/+2
| | | | | | | | | Wait until we know the exact number of ppas to be sent to the device, before allocating the bio. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: simplify data validity check on GCJavier González2017-10-131-16/+7
| | | | | | | | | | | | | | | | | | | | 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>
* lightnvm: pblk: use constant for GC max inflightJavier González2017-10-131-1/+1
| | | | | | | | | Use a constant to set the maximum number of inflight GC requests allowed. Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: do not use a mempool for line bitmapsJavier González2017-10-131-3/+0
| | | | | | | | | | | | | | pblk holds two sector bitmaps: one to keep track of the mapped sectors while the line is active and another one to keep track of the invalid sectors. The latter is kept during the whole live of the line, until it is recycled. Since we cannot guarantee forward progress for the mempool in this case, get rid of the mempool and simply allocate memory through kmalloc. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: decouple read/erase mempoolsJavier González2017-10-131-2/+3
| | | | | | | | | | Since read and erase paths offer different guarantees for inflight I/Os, separate the mempools to set the right min_nr for each on creation. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: simplify work_queue mempoolJavier González2017-10-131-5/+6
| | | | | | | | | | | | | | | | | | | | In pblk, we have a mempool to allocate a generic structure that we pass along workqueues. This is heavily used in the GC path in order to have enough inflight reads and fully utilize the GC bandwidth. However, the current GC path copies data to the host memory and puts it back into the write buffer. This requires a vmalloc allocation for the data and a memory copy. Thus, guaranteeing the allocation by using a mempool for the structure in itself does not give us much. Until we implement support for vector copy to avoid moving data through the host, just allocate the workqueue structure using kmalloc. This allows us to have a much smaller mempool. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: fix min size for page mempoolJavier González2017-10-131-1/+1
| | | | | | | | | | | | | | | | | | | | pblk uses an internal page mempool for allocating pages on internal bios. The main two users of this memory pool are partial reads (reads with some sectors in cache and some on media) and padded writes, which need to add dummy pages to an existing bio already containing valid data (and with a large enough bioset allocated). In both cases, the maximum number of pages per bio is defined by the maximum number of physical sectors supported by the underlying device. This patch fixes a bad mempool allocation, where the min_nr of elements on the pool was fixed (to 16), which is lower than the maximum number of sectors supported by NVMe (as of the time for this patch). Instead, use the maximum number of allowed sectors reported by the device. Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: avoid deadlock on low LUN configJavier González2017-10-131-0/+2
| | | | | | | | | | On low LUN configurations, make sure not to send bios that are bigger than the buffer size. Fixes: a4bd217b4326 ("lightnvm: physical block device (pblk) target") Signed-off-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: reuse pblk_gc_should_kickRakesh Pandit2017-10-131-1/+0
| | | | | | | | | | | This is a trivial change which reuses pblk_gc_should_kick instead of repeating it again in pblk_rl_free_lines_inc. Signed-off-by: Rakesh Pandit <rakesh@tuxera.com> Made it apply to the common case. Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: print incompatible line version correctlyRakesh Pandit2017-10-131-0/+1
| | | | | | | | | | Correct it by converting little endian to cpu endian and also define a macro for line version so that maintenance is easy. Signed-off-by: Rakesh Pandit <rakesh@tuxera.com> Reviewed-by: Javier González <javier@cnexlabs.com> Signed-off-by: Matias Bjørling <m@bjorling.me> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: advance bio according to lba indexJavier González2017-07-281-1/+1
| | | | | | | | | | | | | | | | | | | | | | When a lba either hits the cache or corresponds to an empty entry in the L2P table, we need to advance the bio according to the position in which the lba is located. Otherwise, we will copy data in the wrong page, thus causing data corruption for the application. In case of a cache hit, we assumed that bio->bi_iter.bi_idx would contain the correct index, but this is no necessarily true. Instead, use the local bio advance counter and iterator. This guarantees that lbas hitting the cache are copied into the right bv_page. In case of an empty L2P entry, we omitted to advance the bio. In the cases when the same I/O also contains a cache hit, data corresponding to this lba will be copied to the wrong bv_page. Fix this by advancing the bio as we do in the case of a cache hit. Fixes: a4bd217b4326 lightnvm: physical block device (pblk) target Signed-off-by: Javier González <javier@javigon.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* lightnvm: pblk: control I/O flow also on tear downJavier González2017-07-071-0/+2
| | | | | | | | | 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: verify that cache read is still validJavier González2017-06-301-1/+9
| | | | | | | | | | | | | | | | | | When a read is directed to the cache, we risk that the lba has been updated during the time we made the L2P table lookup and the time we are actually reading form the cache. We intentionally not hold the L2P lock not to block other threads. While strict ordering is not a guarantee at this level (unless REQ_FLUSH has been previously issued), we have experience that some databases that have recently implemented direct I/O support, issue metadata reads very close to the writes, without issuing a fsync in the middle. An easy way to support them while they is to make an extra effort and check the L2P map right before reading the cache. 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 González2017-06-301-0/+8
| | | | | | | | | | 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 vmalloc for GC data bufferJavier González2017-06-301-2/+2
| | | | | | | | | | | For now, we allocate a per I/O buffer for GC data. Since the potential size of the buffer is 256KB and GC is not in the fast path, do this allocation with vmalloc. This puts lets pressure on the memory allocator at no performance cost. 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 González2017-06-261-4/+23
| | | | | | | | | | | | | | | | | | | | | | 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: set mempool and workqueue params.Javier González2017-06-261-2/+11
| | | | | | | | | | | | 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>
* lightnvm: pblk: redesign GC algorithmJavier González2017-06-261-20/+46
| | | | | | | | | | | | | | | | | | | | At the moment, in order to get enough read parallelism, we have recycled several lines at the same time. This approach has proven not to work well when reaching capacity, since we end up mixing valid data from all lines, thus not maintaining a sustainable free/recycled line ratio. The new design, relies on a two level workqueue mechanism. In the first level, we read the metadata for a number of lines based on the GC list they reside on (this is governed by the number of valid sectors in each line). In the second level, we recycle a single line at a time. Here, we issue reads in parallel, while a single GC write thread places data in the write buffer. This design allows to (i) only move data from one line at a time, thus maintaining a sane free/recycled ration and (ii) maintain the GC writer busy with recycled data. 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: simplify meta. memory allocationJavier González2017-06-261-1/+0
| | | | | | | | | | 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>
* lightnvm: pblk: issue multiplane reads if possibleJavier González2017-06-261-2/+20
| | | | | | | | | | 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 González2017-06-261-4/+2
| | | | | | | | | | | 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 González2017-06-261-27/+87
| | | | | | | | | | | | | | | | | | | | | | | | 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 González2017-06-261-6/+6
| | | | | | | | | | 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: generalize erase pathJavier González2017-06-261-7/+4
| | | | | | | | | | | | | | | | 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>
OpenPOWER on IntegriCloud