[2.2] Backport some ZIL, BRT and prefetcher patches #16106
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... by checking that previous block is fully written and flushed. It allows to skip commit delays since we can give up on aggregation in that case. This removes zil_min_commit_timeout parameter, since for single-threaded workloads it is not needed at all, while on very fast devices even some multi-threaded workloads may get detected as single-threaded and still bypass the wait. To give multi-threaded workloads more aggregation chances increase zfs_commit_timeout_pct from 5 to 10%, as they should suffer less from additional latency. Also single-threaded workloads detection allows in perspective better prediction of the next block size. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Prakash Surya <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15381
- Generalize vdev_nowritecache handling by traversing through the VDEV tree and skipping children ZIOs where not supported. - Remove intermediate zio_null() in case of several VDEV children. - Remove children handling from zio_ioctl(). There are no other use cases for this code beside DKIOCFLUSHWRITECACHED, and would there be, I doubt they would so straightforward apply to all VDEV children. Comparing to removed previous optimization this should improve cases of redundant ZILs/SLOGs. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Wilson <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15515
Track history in context of bursts, not individual log blocks. It allows to not blow away all the history by single large burst of many block, and same time allows optimizations covering multiple blocks in a burst and even predicted following burst. For each burst account its optimal block size and minimal first block size. Use that statistics from the last 8 bursts to predict first block size of the next burst. Remove predefined set of block sizes. Allocate any size we see fit, multiple of 4KB, as required by ZIL now. With compression enabled by default, ZFS already writes pretty random block sizes, so this should not surprise space allocator any more. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15635
While picking parts from openzfs#14909 I've missed Linux tracing specific ones, that went unnoticed in default configurations, but breaks the build in some. Reviewed-by: Ameer Hamza <[email protected]> Reviewed-by: Brian Atkinson <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15730
- Split dmu_prefetch_dnode() from dmu_prefetch() into a separate function. It is quite inconvenient to read the code where len = 0 means dnode prefetch instead indirect/data prefetch. One function doing both has no benefits, since the code paths are independent. - Improve dmu_prefetch() handling of long block ranges. Instead of limiting L0 data length to prefetch for to dmu_prefetch_max, make dmu_prefetch_max limit the actual amount of prefetch at the specified level, and, if there is more, prefetch all the rest at higher indirection level. It should improve random access times within the prefetched range of any length, reducing importance of specific dmu_prefetch_max value. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15076
This changes taskq_thread_should_stop() to limit maximum exit rate for idle threads to one per 5 seconds. I believe the previous one was broken, not allowing any thread exits for tasks arriving more than one at a time and so completing while others are running. Also while there: - Remove taskq_thread_spawn() calls on task allocation errors. - Remove extra taskq_thread_should_stop() call. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Rich Ercolani <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15873
Before this change resume token was updated only on data receive. Usually it is enough to resume replication without much overlap. But we've got a report of a curios case, where replication source was traversed with recursive grep, which through enabled atime modified every object without modifying any data. It produced several gigabytes of replication traffic without a single data write and so without a single resume point. While the resume token was not designed to resume from an object, I've found that the send implementation always sends object before any data. So by requesting resume from offset 0 we are effectively resuming from the object, followed (or not) by the data at offset 0, just as we need it. Reviewed-by: Allan Jude <[email protected]> Reviewed-by: Paul Dagnelie <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15927
It does not look important how exactly brt_pending_tree is sorted. When cloning large file, it is quite likely that all of its blocks have identical physical birth times, so comparing them first does not provide useful entropy, while accesses additional cache line. In most cases combination of vdev and offset provides unique result and physical birth time comparison is not even needed. Meanwhile, when traversing the tree inside brt_pending_apply(), it can be beneficial for dbuf cache and CPU cache hits to group processing by vdev and so by the per-VDEV BRT ZAPs. Reviewed-by: Rob Norris <[email protected]> Reviewed-by: Brian Atkinson <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15954
- Remove custom zap_memset(), use regular memset(). - Use PANIC() instead of opaque cmn_err(CE_PANIC). - Provide entry parameter to zap_leaf_rehash_entry(). - Reduce branching in zap_leaf_array_create() inner loop. - Remove signedness where it should not be. Should be no function changes. Reviewed-by: Brian Atkinson <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15976
If there is a pending entry for this block, then we've already issued BRT prefetch for it within this TXG, so don't do it again. BRT vdev lookup and following zap_prefetch_uint64() call can be pretty expensive and should be avoided when not necessary. Reviewed-by: Pawel Jakub Dawidek <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15941
Before this change ZAP called dnode_hold() for almost every block access, that was clearly visible in profiler under heavy load, such as BRT. This patch makes it always hold the dnode reference between zap_lockdir() and zap_unlockdir(). It allows to avoid most of dnode operations between those. It also adds several new _by_dnode() APIs to ZAP and uses them in BRT code. Also adds dmu_prefetch_by_dnode() variant and uses it in the ZAP code. After this there remains only one call to dmu_buf_dnode_enter(), which seems to be unneeded. So remove the call and the functions. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15951
Since brt_pending_apply() is running in syncing context, no other brt_pending_tree accesses are possible for the TXG. We don't need to acquire brt_pending_lock here. Reviewed-by: Pawel Jakub Dawidek <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Brian Atkinson <[email protected]> Reviewed-by: Rob Norris <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15955
Similar to DDT make BRT data and indirect block sizes configurable via module parameters. I am not sure what would be the best yet, but similar to DDT 4KB blocks kill all chances of compression on vdev with ashift=12 or more, that on my tests reaches 3x. While here, fix documentation for respective DDT parameters. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15967
Unlike DDT, where ZAP values may have different lengths due to compression, all BRT entries are identical 8-byte counters. It does not make sense to first fetch the length only to assert it. zap_lookup_uint64() is specifically designed to work with counters of different size and should return error if something odd found. Calling it straight allows to save some measurable CPU time. Reviewed-by: Pawel Jakub Dawidek <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Rob Norris <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15950
- When reading L0 block pointers handle buffers without ones and without dirty records as a holes. Those appear when dnode size was increased, but the end was never written, so there are no new indirection levels to store the pointers. It makes no sense to return EAGAIN here, since sync won't create new indirection levels until there will be actual writes. - When cloning blocks set destination hole logical birth time to the current TXG. Otherwise if we are cloning over existing data, newly created holes may not be properly replicated later. Use BP_SET_BIRTH() when possible to not replicate its logic. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#15994 Closes openzfs#16007
It should not normally happen, but if it does, better to not fail everything for no good reason, or it may be hard to debug. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16007
This should allow to catch some leaks, if those happen. While there fix some cosmetic issues. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16007
Previous code reported non-ZIO errors only via return value, but not via parent ZIO. It could cause NULL-dereference panics due to dmu_buf_hold_array_by_dnode() ignoring the return value, relying solely on parent ZIO status. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Ameer Hamza <[email protected]> Reported by: Ameer Hamza <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16042
Investigating read errors triggering panic fixed in openzfs#16042 I've found that we have a race in a sync process between the moment dirty record for cloned block is removed and the moment dbuf is destroyed. If dmu_buf_hold_array_by_dnode() take a hold on a cloned dbuf before it is synced/destroyed, then dbuf_read_impl() may see it still in DB_NOFILL state, but without the dirty record. Such case is not an error, but equivalent to DB_UNCACHED, since the dbuf block pointer is already updated by dbuf_write_ready(). Unfortunately it is impossible to safely change the dbuf state to DB_UNCACHED there, since there may already be another cloning in progress, that dropped dbuf lock before creating a new dirty record, protected only by the range lock. Reviewed-by: Rob Norris <[email protected]> Reviewed-by: Robert Evans <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16052
Before this change speculative prefetcher was able to detect a stream only if all of its accesses are perfectly sequential. It was easy to implement and is perfectly fine for single-threaded applications. Unfortunately multi-threaded network servers, such as iSCSI, SMB or NFS usually have plenty of threads and may often reorder requests, preventing successful speculation and prefetch. This change allows speculative prefetcher to detect streams even if requests are reordered by introducing a list of 9 non-contiguous ranges up to 16MB ahead of current stream position and filling the gaps as more requests arrive. It also allows stream to proceed even with holes up to a certain configurable threshold (25%). Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16022
Syncing context should not depend on current state of dbuf, which could already change several times in later transaction groups, but rely solely on dirty record for the transaction group being synced. Some of the checks seem already impossible, while instead of others I think we should better check for absence of data in the specific dirty record rather than DB_NOFILL. Reviewed-by: Robert Evans <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16057
When after openzfs#16022 adding new range we aggregate more than two existing ranges, that should be very rare, only if several streams overlap, we may need to zero not the last range, but some earlier. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16072
Previous code held ARC state sublist lock throughout all L2ARC write process, which included number of allocations and even ZIO issues. Being blocked in any of those places the code could also block ARC eviction, that could cause OOM activation or even dead- lock if system is low on memory or one is too fragmented. Fix it by dropping the lock as soon as we see a block eligible for L2ARC writing and pick it up later using earlier inserted marker. While there, also reduce scope of hash lock, moving ZIO allocation and other operations not requiring header access out of it. All operations requiring header access move under hash lock, since L2_WRITING flag does not prevent header eviction only transition to arc_l2c_only state with L1 header. To be able to manipulate sublist lock and marker as needed add few more multilist functions and modify one. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Sponsored by: iXsystems, Inc. Closes openzfs#16040
amotin
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tonyhutter
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Apr 17, 2024
behlendorf
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Apr 19, 2024
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