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* Gang ABD TypeBrian Atkinson2020-05-201-20/+46
| | | | | | | | | | | | | | | Adding the gang ABD type, which allows for linear and scatter ABDs to be chained together into a single ABD. This can be used to avoid doing memory copies to/from ABDs. An example of this can be found in vdev_queue.c in the vdev_queue_aggregate() function. Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Co-authored-by: Brian <[email protected]> Co-authored-by: Mark Maybee <[email protected]> Signed-off-by: Brian Atkinson <[email protected]> Closes #10069
* Reduce loaded range tree memory usagePaul Dagnelie2019-10-091-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements a new tree structure for ZFS, and uses it to store range trees more efficiently. The new structure is approximately a B-tree, though there are some small differences from the usual characterizations. The tree has core nodes and leaf nodes; each contain data elements, which the elements in the core nodes acting as separators between its children. The difference between core and leaf nodes is that the core nodes have an array of children, while leaf nodes don't. Every node in the tree may be only partially full; in most cases, they are all at least 50% full (in terms of element count) except for the root node, which can be less full. Underfull nodes will steal from their neighbors or merge to remain full enough, while overfull nodes will split in two. The data elements are contained in tree-controlled buffers; they are copied into these on insertion, and overwritten on deletion. This means that the elements are not independently allocated, which reduces overhead, but also means they can't be shared between trees (and also that pointers to them are only valid until a side-effectful tree operation occurs). The overhead varies based on how dense the tree is, but is usually on the order of about 50% of the element size; the per-node overheads are very small, and so don't make a significant difference. The trees can accept arbitrary records; they accept a size and a comparator to allow them to be used for a variety of purposes. The new trees replace the AVL trees used in the range trees today. Currently, the range_seg_t structure contains three 8 byte integers of payload and two 24 byte avl_tree_node_ts to handle its storage in both an offset-sorted tree and a size-sorted tree (total size: 64 bytes). In the new model, the range seg structures are usually two 4 byte integers, but a separate one needs to exist for the size-sorted and offset-sorted tree. Between the raw size, the 50% overhead, and the double storage, the new btrees are expected to use 8*1.5*2 = 24 bytes per record, or 33.3% as much memory as the AVL trees (this is for the purposes of storing metaslab range trees; for other purposes, like scrubs, they use ~50% as much memory). We reduced the size of the payload in the range segments by teaching range trees about starting offsets and shifts; since metaslabs have a fixed starting offset, and they all operate in terms of disk sectors, we can store the ranges using 4-byte integers as long as the size of the metaslab divided by the sector size is less than 2^32. For 512-byte sectors, this is a 2^41 (or 2TB) metaslab, which with the default settings corresponds to a 256PB disk. 4k sector disks can handle metaslabs up to 2^46 bytes, or 2^63 byte disks. Since we do not anticipate disks of this size in the near future, there should be almost no cases where metaslabs need 64-byte integers to store their ranges. We do still have the capability to store 64-byte integer ranges to account for cases where we are storing per-vdev (or per-dnode) trees, which could reasonably go above the limits discussed. We also do not store fill information in the compact version of the node, since it is only used for sorted scrub. We also optimized the metaslab loading process in various other ways to offset some inefficiencies in the btree model. While individual operations (find, insert, remove_from) are faster for the btree than they are for the avl tree, remove usually requires a find operation, while in the AVL tree model the element itself suffices. Some clever changes actually caused an overall speedup in metaslab loading; we use approximately 40% less cpu to load metaslabs in our tests on Illumos. Another memory and performance optimization was achieved by changing what is stored in the size-sorted trees. When a disk is heavily fragmented, the df algorithm used by default in ZFS will almost always find a number of small regions in its initial cursor-based search; it will usually only fall back to the size-sorted tree to find larger regions. If we increase the size of the cursor-based search slightly, and don't store segments that are smaller than a tunable size floor in the size-sorted tree, we can further cut memory usage down to below 20% of what the AVL trees store. This also results in further reductions in CPU time spent loading metaslabs. The 16KiB size floor was chosen because it results in substantial memory usage reduction while not usually resulting in situations where we can't find an appropriate chunk with the cursor and are forced to use an oversized chunk from the size-sorted tree. In addition, even if we do have to use an oversized chunk from the size-sorted tree, the chunk would be too small to use for ZIL allocations, so it isn't as big of a loss as it might otherwise be. And often, more small allocations will follow the initial one, and the cursor search will now find the remainder of the chunk we didn't use all of and use it for subsequent allocations. Practical testing has shown little or no change in fragmentation as a result of this change. If the size-sorted tree becomes empty while the offset sorted one still has entries, it will load all the entries from the offset sorted tree and disregard the size floor until it is unloaded again. This operation occurs rarely with the default setting, only on incredibly thoroughly fragmented pools. There are some other small changes to zdb to teach it to handle btrees, but nothing major. Reviewed-by: George Wilson <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed by: Sebastien Roy [email protected] Reviewed-by: Igor Kozhukhov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Closes #9181
* Make module tunables cross platformMatthew Macy2019-09-051-52/+32
| | | | | | | | | | | Adds ZFS_MODULE_PARAM to abstract module parameter setting to operating systems other than Linux. Reviewed-by: Jorgen Lundman <[email protected]> Reviewed-by: Igor Kozhukhov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Matt Macy <[email protected]> Signed-off-by: Ryan Moeller <[email protected]> Closes #9230
* Fix typos in module/zfs/Andrea Gelmini2019-09-021-1/+1
| | | | | | | | Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Ryan Moeller <[email protected]> Reviewed-by: Richard Laager <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Andrea Gelmini <[email protected]> Closes #9240
* Move write aggregation memory copy out of vq_lockAlexander Motin2019-06-131-10/+12
| | | | | | | | | | | | | | | | | | | Memory copy is too heavy operation to do under the congested lock. Moving it out reduces congestion by many times to almost invisible. Since the original zio removed from the queue, and the child zio is not executed yet, I don't see why would the copy need protection. My guess it just remained like this from the time when lock was not dropped here, which was added later to fix lock ordering issue. Multi-threaded sequential write tests with both HDD and SSD pools with ZVOL block sizes of 4KB, 16KB, 64KB and 128KB all show major reduction of lock congestion, saving from 15% to 35% of CPU time and increasing throughput from 10% to 40%. Reviewed-by: Richard Yao <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Closes #8890
* Add TRIM supportBrian Behlendorf2019-03-291-10/+57
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UNMAP/TRIM support is a frequently-requested feature to help prevent performance from degrading on SSDs and on various other SAN-like storage back-ends. By issuing UNMAP/TRIM commands for sectors which are no longer allocated the underlying device can often more efficiently manage itself. This TRIM implementation is modeled on the `zpool initialize` feature which writes a pattern to all unallocated space in the pool. The new `zpool trim` command uses the same vdev_xlate() code to calculate what sectors are unallocated, the same per- vdev TRIM thread model and locking, and the same basic CLI for a consistent user experience. The core difference is that instead of writing a pattern it will issue UNMAP/TRIM commands for those extents. The zio pipeline was updated to accommodate this by adding a new ZIO_TYPE_TRIM type and associated spa taskq. This new type makes is straight forward to add the platform specific TRIM/UNMAP calls to vdev_disk.c and vdev_file.c. These new ZIO_TYPE_TRIM zios are handled largely the same way as ZIO_TYPE_READs or ZIO_TYPE_WRITEs. This makes it possible to largely avoid changing the pipieline, one exception is that TRIM zio's may exceed the 16M block size limit since they contain no data. In addition to the manual `zpool trim` command, a background automatic TRIM was added and is controlled by the 'autotrim' property. It relies on the exact same infrastructure as the manual TRIM. However, instead of relying on the extents in a metaslab's ms_allocatable range tree, a ms_trim tree is kept per metaslab. When 'autotrim=on', ranges added back to the ms_allocatable tree are also added to the ms_free tree. The ms_free tree is then periodically consumed by an autotrim thread which systematically walks a top level vdev's metaslabs. Since the automatic TRIM will skip ranges it considers too small there is value in occasionally running a full `zpool trim`. This may occur when the freed blocks are small and not enough time was allowed to aggregate them. An automatic TRIM and a manual `zpool trim` may be run concurrently, in which case the automatic TRIM will yield to the manual TRIM. Reviewed-by: Jorgen Lundman <[email protected]> Reviewed-by: Tim Chase <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: George Wilson <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Contributions-by: Saso Kiselkov <[email protected]> Contributions-by: Tim Chase <[email protected]> Contributions-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #8419 Closes #598
* Add separate aggregation limit for non-rotating mediaAlexander Motin2019-03-131-1/+10
| | | | | | | | | | | | | | | Before sequential scrub patches ZFS never aggregated I/Os above 128KB. Sequential scrub bumped that to 1MB, supposedly to reduce number of head seeks for spinning disks. But for SSDs it makes little to no sense, especially on FreeBSD, where due to MAXPHYS limitation device will likely still see bunch of 128KB I/Os instead of one large. Having more strict aggregation limit for SSDs allows to avoid allocation of large memory buffer and copy to/from it, that is a serious problem when throughput reaches gigabytes per second. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Richard Elling <[email protected]> Signed-off-by: Alexander Motin <[email protected]> Closes #8494
* OpenZFS 9102 - zfs should be able to initialize storage devicesGeorge Wilson2019-01-071-6/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PROBLEM ======== The first access to a block incurs a performance penalty on some platforms (e.g. AWS's EBS, VMware VMDKs). Therefore we recommend that volumes are "thick provisioned", where supported by the platform (VMware). This can create a large delay in getting a new virtual machines up and running (or adding storage to an existing Engine). If the thick provision step is omitted, write performance will be suboptimal until all blocks on the LUN have been written. SOLUTION ========= This feature introduces a way to 'initialize' the disks at install or in the background to make sure we don't incur this first read penalty. When an entire LUN is added to ZFS, we make all space available immediately, and allow ZFS to find unallocated space and zero it out. This works with concurrent writes to arbitrary offsets, ensuring that we don't zero out something that has been (or is in the middle of being) written. This scheme can also be applied to existing pools (affecting only free regions on the vdev). Detailed design: - new subcommand:zpool initialize [-cs] <pool> [<vdev> ...] - start, suspend, or cancel initialization - Creates new open-context thread for each vdev - Thread iterates through all metaslabs in this vdev - Each metaslab: - select a metaslab - load the metaslab - mark the metaslab as being zeroed - walk all free ranges within that metaslab and translate them to ranges on the leaf vdev - issue a "zeroing" I/O on the leaf vdev that corresponds to a free range on the metaslab we're working on - continue until all free ranges for this metaslab have been "zeroed" - reset/unmark the metaslab being zeroed - if more metaslabs exist, then repeat above tasks. - if no more metaslabs, then we're done. - progress for the initialization is stored on-disk in the vdev’s leaf zap object. The following information is stored: - the last offset that has been initialized - the state of the initialization process (i.e. active, suspended, or canceled) - the start time for the initialization - progress is reported via the zpool status command and shows information for each of the vdevs that are initializing Porting notes: - Added zfs_initialize_value module parameter to set the pattern written by "zpool initialize". - Added zfs_vdev_{initializing,removal}_{min,max}_active module options. Authored by: George Wilson <[email protected]> Reviewed by: John Wren Kennedy <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: loli10K <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Richard Lowe <[email protected]> Signed-off-by: Tim Chase <[email protected]> Ported-by: Tim Chase <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9102 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c3963210eb Closes #8230
* Fixes for procfs files backed by linked listsJohn Gallagher2018-09-261-20/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | There are some issues with the way the seq_file interface is implemented for kstats backed by linked lists (zfs_dbgmsgs and certain per-pool debugging info): * We don't account for the fact that seq_file sometimes visits a node multiple times, which results in missing messages when read through procfs. * We don't keep separate state for each reader of a file, so concurrent readers will receive incorrect results. * We don't account for the fact that entries may have been removed from the list between read syscalls, so reading from these files in procfs can cause the system to crash. This change fixes these issues and adds procfs_list, a wrapper around a linked list which abstracts away the details of implementing the seq_file interface for a list and exposing the contents of the list through procfs. Reviewed by: Don Brady <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Brad Lewis <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: John Gallagher <[email protected]> External-issue: LX-1211 Closes #7819
* OpenZFS 9112 - Improve allocation performance on high-end systemsPaul Dagnelie2018-07-311-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Overview ======== We parallelize the allocation process by creating the concept of "allocators". There are a certain number of allocators per metaslab group, defined by the value of a tunable at pool open time. Each allocator for a given metaslab group has up to 2 active metaslabs; one "primary", and one "secondary". The primary and secondary weight mean the same thing they did in in the pre-allocator world; primary metaslabs are used for most allocations, secondary metaslabs are used for ditto blocks being allocated in the same metaslab group. There is also the CLAIM weight, which has been separated out from the other weights, but that is less important to understanding the patch. The active metaslabs for each allocator are moved from their normal place in the metaslab tree for the group to the back of the tree. This way, they will not be selected for use by other allocators searching for new metaslabs unless all the passive metaslabs are unsuitable for allocations. If that does happen, the allocators will "steal" from each other to ensure that IOs don't fail until there is truly no space left to perform allocations. In addition, the alloc queue for each metaslab group has been broken into a separate queue for each allocator. We don't want to dramatically increase the number of inflight IOs on low-end systems, because it can significantly increase txg times. On the other hand, we want to ensure that there are enough IOs for each allocator to allow for good coalescing before sending the IOs to the disk. As a result, we take a compromise path; each allocator's alloc queue max depth starts at a certain value for every txg. Every time an IO completes, we increase the max depth. This should hopefully provide a good balance between the two failure modes, while not dramatically increasing complexity. We also parallelize the spa_alloc_tree and spa_alloc_lock, which cause very similar contention when selecting IOs to allocate. This parallelization uses the same allocator scheme as metaslab selection. Performance Results =================== Performance improvements from this change can vary significantly based on the number of CPUs in the system, whether or not the system has a NUMA architecture, the speed of the drives, the values for the various tunables, and the workload being performed. For an fio async sequential write workload on a 24 core NUMA system with 256 GB of RAM and 8 128 GB SSDs, there is a roughly 25% performance improvement. Future Work =========== Analysis of the performance of the system with this patch applied shows that a significant new bottleneck is the vdev disk queues, which also need to be parallelized. Prototyping of this change has occurred, and there was a performance improvement, but more work needs to be done before its stability has been verified and it is ready to be upstreamed. Authored by: Paul Dagnelie <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Alexander Motin <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Gordon Ross <[email protected]> Ported-by: Paul Dagnelie <[email protected]> Signed-off-by: Paul Dagnelie <[email protected]> Porting Notes: * Fix reservation test failures by increasing tolerance. OpenZFS-issue: https://illumos.org/issues/9112 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3f3cc3c3 Closes #7682
* Fix zio->io_priority failed (7 < 6) assertTony Hutter2018-05-291-0/+9
| | | | | | | | | | | | | This fixes an assert in vdev_queue_change_io_priority(): VERIFY3(zio->io_priority < ZIO_PRIORITY_NUM_QUEUEABLE) failed (7 < 6) PANIC at vdev_queue.c:832:vdev_queue_change_io_priority() Reviewed-by: Tom Caputi <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tony Hutter <[email protected]> Closes #7566 Closes #7542
* Update build system and packagingBrian Behlendorf2018-05-291-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Minimal changes required to integrate the SPL sources in to the ZFS repository build infrastructure and packaging. Build system and packaging: * Renamed SPL_* autoconf m4 macros to ZFS_*. * Removed redundant SPL_* autoconf m4 macros. * Updated the RPM spec files to remove SPL package dependency. * The zfs package obsoletes the spl package, and the zfs-kmod package obsoletes the spl-kmod package. * The zfs-kmod-devel* packages were updated to add compatibility symlinks under /usr/src/spl-x.y.z until all dependent packages can be updated. They will be removed in a future release. * Updated copy-builtin script for in-kernel builds. * Updated DKMS package to include the spl.ko. * Updated stale AUTHORS file to include all contributors. * Updated stale COPYRIGHT and included the SPL as an exception. * Renamed README.markdown to README.md * Renamed OPENSOLARIS.LICENSE to LICENSE. * Renamed DISCLAIMER to NOTICE. Required code changes: * Removed redundant HAVE_SPL macro. * Removed _BOOT from nvpairs since it doesn't apply for Linux. * Initial header cleanup (removal of empty headers, refactoring). * Remove SPL repository clone/build from zimport.sh. * Use of DEFINE_RATELIMIT_STATE and DEFINE_SPINLOCK removed due to build issues when forcing C99 compilation. * Replaced legacy ACCESS_ONCE with READ_ONCE. * Include needed headers for `current` and `EXPORT_SYMBOL`. Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Olaf Faaland <[email protected]> Reviewed-by: Matthew Ahrens <[email protected]> Reviewed-by: Pavel Zakharov <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> TEST_ZIMPORT_SKIP="yes" Closes #7556
* OpenZFS 7614, 9064 - zfs device evacuation/removalMatthew Ahrens2018-04-141-4/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | OpenZFS 7614 - zfs device evacuation/removal OpenZFS 9064 - remove_mirror should wait for device removal to complete This project allows top-level vdevs to be removed from the storage pool with "zpool remove", reducing the total amount of storage in the pool. This operation copies all allocated regions of the device to be removed onto other devices, recording the mapping from old to new location. After the removal is complete, read and free operations to the removed (now "indirect") vdev must be remapped and performed at the new location on disk. The indirect mapping table is kept in memory whenever the pool is loaded, so there is minimal performance overhead when doing operations on the indirect vdev. The size of the in-memory mapping table will be reduced when its entries become "obsolete" because they are no longer used by any block pointers in the pool. An entry becomes obsolete when all the blocks that use it are freed. An entry can also become obsolete when all the snapshots that reference it are deleted, and the block pointers that reference it have been "remapped" in all filesystems/zvols (and clones). Whenever an indirect block is written, all the block pointers in it will be "remapped" to their new (concrete) locations if possible. This process can be accelerated by using the "zfs remap" command to proactively rewrite all indirect blocks that reference indirect (removed) vdevs. Note that when a device is removed, we do not verify the checksum of the data that is copied. This makes the process much faster, but if it were used on redundant vdevs (i.e. mirror or raidz vdevs), it would be possible to copy the wrong data, when we have the correct data on e.g. the other side of the mirror. At the moment, only mirrors and simple top-level vdevs can be removed and no removal is allowed if any of the top-level vdevs are raidz. Porting Notes: * Avoid zero-sized kmem_alloc() in vdev_compact_children(). The device evacuation code adds a dependency that vdev_compact_children() be able to properly empty the vdev_child array by setting it to NULL and zeroing vdev_children. Under Linux, kmem_alloc() and related functions return a sentinel pointer rather than NULL for zero-sized allocations. * Remove comment regarding "mpt" driver where zfs_remove_max_segment is initialized to SPA_MAXBLOCKSIZE. Change zfs_condense_indirect_commit_entry_delay_ticks to zfs_condense_indirect_commit_entry_delay_ms for consistency with most other tunables in which delays are specified in ms. * ZTS changes: Use set_tunable rather than mdb Use zpool sync as appropriate Use sync_pool instead of sync Kill jobs during test_removal_with_operation to allow unmount/export Don't add non-disk names such as "mirror" or "raidz" to $DISKS Use $TEST_BASE_DIR instead of /tmp Increase HZ from 100 to 1000 which is more common on Linux removal_multiple_indirection.ksh Reduce iterations in order to not time out on the code coverage builders. removal_resume_export: Functionally, the test case is correct but there exists a race where the kernel thread hasn't been fully started yet and is not visible. Wait for up to 1 second for the removal thread to be started before giving up on it. Also, increase the amount of data copied in order that the removal not finish before the export has a chance to fail. * MMP compatibility, the concept of concrete versus non-concrete devices has slightly changed the semantics of vdev_writeable(). Update mmp_random_leaf_impl() accordingly. * Updated dbuf_remap() to handle the org.zfsonlinux:large_dnode pool feature which is not supported by OpenZFS. * Added support for new vdev removal tracepoints. * Test cases removal_with_zdb and removal_condense_export have been intentionally disabled. When run manually they pass as intended, but when running in the automated test environment they produce unreliable results on the latest Fedora release. They may work better once the upstream pool import refectoring is merged into ZoL at which point they will be re-enabled. Authored by: Matthew Ahrens <[email protected]> Reviewed-by: Alex Reece <[email protected]> Reviewed-by: George Wilson <[email protected]> Reviewed-by: John Kennedy <[email protected]> Reviewed-by: Prakash Surya <[email protected]> Reviewed by: Richard Laager <[email protected]> Reviewed by: Tim Chase <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Garrett D'Amore <[email protected]> Ported-by: Tim Chase <[email protected]> Signed-off-by: Tim Chase <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7614 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f539f1eb Closes #6900
* Fix deadlock in IO pipelineBrian Behlendorf2018-03-161-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In vdev_queue_aggregate() the zio_execute() bypass should not be called under the vdev queue lock. This can result in a deadlock as shown in the stack traces below. Drop the vdev queue lock then walk the parents of the aggregate IO to determine the list of component IOs to be bypassed. This can be done safely without holding the io_lock since the new aggregate IO has not yet been returned and its parents cannot change. --- THREAD 1 --- arc_read() zio_nowait() zio_vdev_io_start() vdev_queue_io() <--- mutex_enter(vq->vq_lock) vdev_queue_io_to_issue() vdev_queue_aggregate() zio_execute() zio_vdev_io_assess() zio_wait_for_children() <- mutex_enter(zio->io_lock) --- THREAD 2 --- (inverse order) arc_read() zio_change_priority() <- mutex_enter(zio->zio_lock) vdev_queue_change_io_priority() <- mutex_enter(vq->vq_lock) Reviewed-by: Tom Caputi <[email protected]> Reviewed-by: Don Brady <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #7307
* Support re-prioritizing asynchronous prefetchesTom Caputi2017-12-211-0/+42
| | | | | | | | | | | | | | | | | | | | | When sequential scrubs were merged, all calls to arc_read() (including prefetch IOs) were given ZIO_PRIORITY_ASYNC_READ. Unfortunately, this behaves badly with an existing issue where prefetch IOs cannot be re-prioritized after the issue. The result is that synchronous reads end up in the same vdev_queue as the scrub IOs and can have (in some workloads) multiple seconds of latency. This patch incorporates 2 changes. The first ensures that all scrub IOs are given ZIO_PRIORITY_SCRUB to allow the vdev_queue code to differentiate between these I/Os and user prefetches. Second, this patch introduces zio_change_priority() to provide the missing capability to upgrade a zio's priority. Reviewed by: George Wilson <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #6921 Closes #6926
* Sequential scrub and resilversTom Caputi2017-11-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, scrubs and resilvers can take an extremely long time to complete. This is largely due to the fact that zfs scans process pools in logical order, as determined by each block's bookmark. This makes sense from a simplicity perspective, but blocks in zfs are often scattered randomly across disks, particularly due to zfs's copy-on-write mechanisms. This patch improves performance by splitting scrubs and resilvers into a metadata scanning phase and an IO issuing phase. The metadata scan reads through the structure of the pool and gathers an in-memory queue of I/Os, sorted by size and offset on disk. The issuing phase will then issue the scrub I/Os as sequentially as possible, greatly improving performance. This patch also updates and cleans up some of the scan code which has not been updated in several years. Reviewed-by: Brian Behlendorf <[email protected]> Authored-by: Saso Kiselkov <[email protected]> Authored-by: Alek Pinchuk <[email protected]> Authored-by: Tom Caputi <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #3625 Closes #6256
* Undo c89 workarounds to match with upstreamDon Brady2017-11-041-2/+1
| | | | | | | | | With PR 5756 the zfs module now supports c99 and the remaining past c89 workarounds can be undone. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Don Brady <[email protected]> Closes #6816
* vdev_mirror: load balancing fixesGvozden Neskovic2017-08-211-14/+7
| | | | | | | | | | | | | | | | vdev_queue: - Track the last position of each vdev, including the io size, in order to detect linear access of the following zio. - Remove duplicate `vq_lastoffset` vdev_mirror: - Correctly calculate the zio offset (signedness issue) - Deprecate `vdev_queue_register_lastoffset()` - Add `VDEV_LABEL_START_SIZE` to zio offset of leaf vdevs Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Gvozden Neskovic <[email protected]> Closes #6461
* Cap maximum aggregate IO sizeBrian Behlendorf2017-06-271-2/+5
| | | | | | | | | | | | | | Commit 8542ef8 allowed optional IOs to be aggregated beyond the specified aggregation limit. Since the aggregation limit was also used to enforce the maximum block size, setting `zfs_vdev_aggregation_limit=16777216` could result in an attempt to allocate an ABD larger than 16M. Reviewed by: Matthew Ahrens <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #6259 Closes #6270
* Increase zfs_vdev_async_write_min_active to 2DHE2017-04-141-1/+1
| | | | | | | | | | | | | | | | | Resilver operations frequently cause only a small amount of dirty data to be written to disk at a time, resulting in the IO scheduler to only issue 1 write at a time to the resilvering disk. When it is rotational media the drive will often travel past the next sector to be written before receiving a write command from ZFS, significantly delaying the write of the next sector. Raise zfs_vdev_async_write_min_active so that drives are kept fed during resilvering. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: DHE <[email protected]> Issue #4825 Closes #5926
* OpenZFS 8005 - poor performance of 1MB writes on certain RAID-Z configurationsMatthew Ahrens2017-04-101-5/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Authored by: Matt Ahrens <[email protected]> Reviewed by: Saso Kiselkov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Don Brady <[email protected]> Ported-by: Matt Ahrens <[email protected]> RAID-Z requires that space be allocated in multiples of P+1 sectors, because this is the minimum size block that can have the required amount of parity. Thus blocks on RAIDZ1 must be allocated in a multiple of 2 sectors; on RAIDZ2 multiple of 3; and on RAIDZ3 multiple of 4. A sector is a unit of 2^ashift bytes, typically 512B or 4KB. To satisfy this constraint, the allocation size is rounded up to the proper multiple, resulting in up to 3 "pad sectors" at the end of some blocks. The contents of these pad sectors are not used, so we do not need to read or write these sectors. However, some storage hardware performs much worse (around 1/2 as fast) on mostly-contiguous writes when there are small gaps of non-overwritten data between the writes. Therefore, ZFS creates "optional" zio's when writing RAID-Z blocks that include pad sectors. If writing a pad sector will fill the gap between two (required) writes, we will issue the optional zio, thus doubling performance. The gap-filling performance improvement was introduced in July 2009. Writing the optional zio is done by the io aggregation code in vdev_queue.c. The problem is that it is also subject to the limit on the size of aggregate writes, zfs_vdev_aggregation_limit, which is by default 128KB. For a given block, if the amount of data plus padding written to a leaf device exceeds zfs_vdev_aggregation_limit, the optional zio will not be written, resulting in a ~2x performance degradation. The problem occurs only for certain values of ashift, compressed block size, and RAID-Z configuration (number of parity and data disks). It cannot occur with the default recordsize=128KB. If compression is enabled, all configurations with recordsize=1MB or larger will be impacted to some degree. The problem notably occurs with recordsize=1MB, compression=off, with 10 disks in a RAIDZ2 or RAIDZ3 group (with 512B or 4KB sectors). Therefore this problem has been known as "the 1MB 10-wide RAIDZ2 (or 3) problem". The problem also occurs with the following configurations: With recordsize=512KB or 256KB, compression=off, the problem occurs only in rarely-used configurations: * 4-wide RAIDZ1 with recordsize=512KB and ashift=12 (4KB sectors) * 4-wide RAIDZ2 (either recordsize, either ashift) * 5-wide RAIDZ2 with recordsize=512KB (either ashift) * 6-wide RAIDZ2 with recordsize=512KB (either ashift) With recordsize=1MB, compression=off, ashift=9 (512B sectors) * RAIDZ1 with 4 or 8 disks * RAIDZ2 with 4, 8, or 10 disks * RAIDZ3 with 6, 8, 9, or 10 disks With recordsize=1MB, compression=off, ashift=12 (4KB sectors) * RAIDZ1 with 7 or 8 disks * RAIDZ2 with 4, 5, or 10 disks * RAIDZ3 with 6, 9, or 10 disks With recordsize=2MB and larger (which can only be selected by changing kernel tunables), many configurations are affected, including with higher numbers of disks (up to 18 disks with recordsize=2MB). Increase zfs_vdev_aggregation_limit to allow the optional zio to be aggregated, thus eliminating the problem. Setting it to 256KB fixes all commonly-used configurations. The solution is to aggregate optional zio's regardless of the aggregation size limit. Analysis sponsored by Intel Corp. OpenZFS-issue: https://www.illumos.org/issues/8005 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/321 Closes #5931
* Use cstyle -cpP in `make cstyle` checkBrian Behlendorf2016-12-121-5/+5
| | | | | | | | | | | | | | | | | | | | | | | Enable picky cstyle checks and resolve the new warnings. The vast majority of the changes needed were to handle minor issues with whitespace formatting. This patch contains no functional changes. Non-whitespace changes are as follows: * 8 times ; to { } in for/while loop * fix missing ; in cmd/zed/agents/zfs_diagnosis.c * comment (confim -> confirm) * change endline , to ; in cmd/zpool/zpool_main.c * a number of /* BEGIN CSTYLED */ /* END CSTYLED */ blocks * /* CSTYLED */ markers * change == 0 to ! * ulong to unsigned long in module/zfs/dsl_scan.c * rearrangement of module_param lines in module/zfs/metaslab.c * add { } block around statement after for_each_online_node Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Håkan Johansson <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #5465
* DLPX-44812 integrate EP-220 large memory scalabilityDavid Quigley2016-11-291-12/+12
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* OpenZFS 7090 - zfs should throttle allocationsDon Brady2016-10-131-1/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | OpenZFS 7090 - zfs should throttle allocations Authored by: George Wilson <[email protected]> Reviewed by: Alex Reece <[email protected]> Reviewed by: Christopher Siden <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: Sebastien Roy <[email protected]> Approved by: Matthew Ahrens <[email protected]> Ported-by: Don Brady <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> When write I/Os are issued, they are issued in block order but the ZIO pipeline will drive them asynchronously through the allocation stage which can result in blocks being allocated out-of-order. It would be nice to preserve as much of the logical order as possible. In addition, the allocations are equally scattered across all top-level VDEVs but not all top-level VDEVs are created equally. The pipeline should be able to detect devices that are more capable of handling allocations and should allocate more blocks to those devices. This allows for dynamic allocation distribution when devices are imbalanced as fuller devices will tend to be slower than empty devices. The change includes a new pool-wide allocation queue which would throttle and order allocations in the ZIO pipeline. The queue would be ordered by issued time and offset and would provide an initial amount of allocation of work to each top-level vdev. The allocation logic utilizes a reservation system to reserve allocations that will be performed by the allocator. Once an allocation is successfully completed it's scheduled on a given top-level vdev. Each top-level vdev maintains a maximum number of allocations that it can handle (mg_alloc_queue_depth). The pool-wide reserved allocations (top-levels * mg_alloc_queue_depth) are distributed across the top-level vdevs metaslab groups and round robin across all eligible metaslab groups to distribute the work. As top-levels complete their work, they receive additional work from the pool-wide allocation queue until the allocation queue is emptied. OpenZFS-issue: https://www.illumos.org/issues/7090 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/4756c3d7 Closes #5258 Porting Notes: - Maintained minimal stack in zio_done - Preserve linux-specific io sizes in zio_write_compress - Added module params and documentation - Updated to use optimize AVL cmp macros
* Performance optimization of AVL tree comparator functionsGvozden Neskovic2016-08-311-22/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | perf: 2.75x faster ddt_entry_compare() First 256bits of ddt_key_t is a block checksum, which are expected to be close to random data. Hence, on average, comparison only needs to look at first few bytes of the keys. To reduce number of conditional jump instructions, the result is computed as: sign(memcmp(k1, k2)). Sign of an integer 'a' can be obtained as: `(0 < a) - (a < 0)` := {-1, 0, 1} , which is computed efficiently. Synthetic performance evaluation of original and new algorithm over 1G random keys on 2.6GHz Intel(R) Xeon(R) CPU E5-2660 v3: old 6.85789 s new 2.49089 s perf: 2.8x faster vdev_queue_offset_compare() and vdev_queue_timestamp_compare() Compute the result directly instead of using conditionals perf: zfs_range_compare() Speedup between 1.1x - 2.5x, depending on compiler version and optimization level. perf: spa_error_entry_compare() `bcmp()` is not suitable for comparator use. Use `memcmp()` instead. perf: 2.8x faster metaslab_compare() and metaslab_rangesize_compare() perf: 2.8x faster zil_bp_compare() perf: 2.8x faster mze_compare() perf: faster dbuf_compare() perf: faster compares in spa_misc perf: 2.8x faster layout_hash_compare() perf: 2.8x faster space_reftree_compare() perf: libzfs: faster avl tree comparators perf: guid_compare() perf: dsl_deadlist_compare() perf: perm_set_compare() perf: 2x faster range_tree_seg_compare() perf: faster unique_compare() perf: faster vdev_cache _compare() perf: faster vdev_uberblock_compare() perf: faster fuid _compare() perf: faster zfs_znode_hold_compare() Signed-off-by: Gvozden Neskovic <[email protected]> Signed-off-by: Richard Elling <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #5033
* Fix self-healing IO prior to dsl_pool_init() completionGeLiXin2016-05-271-3/+12
| | | | | | | | | | | | | | | | | | | | | Async writes triggered by a self-healing IO may be issued before the pool finishes the process of initialization. This results in a NULL dereference of `spa->spa_dsl_pool` in vdev_queue_max_async_writes(). George Wilson recommended addressing this issue by initializing the passed `dsl_pool_t **` prior to dmu_objset_open_impl(). Since the caller is passing the `spa->spa_dsl_pool` this has the effect of ensuring it's initialized. However, since this depends on the caller knowing they must pass the `spa->spa_dsl_pool` an additional NULL check was added to vdev_queue_max_async_writes(). This guards against any future restructuring of the code which might result in dsl_pool_init() being called differently. Signed-off-by: GeLiXin <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #4652
* OpenZFS 6531 - Provide mechanism to artificially limit disk performanceTony Hutter2016-05-261-3/+0
| | | | | | | | | | | | | | | | | | | Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Approved by: Dan McDonald <[email protected]> Ported by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/6531 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/97e8130 Porting notes: - Added new IO delay tracepoints, and moved common ZIO tracepoint macros to a new trace_common.h file. - Used zio_delay_taskq() in place of OpenZFS's timeout_generic() function. - Updated zinject man page - Updated zpool_scrub test files
* FreeBSD r256956: Improve ZFS N-way mirror read performance by using load and ↵smh2016-02-261-0/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | locality information. The existing algorithm selects a preferred leaf vdev based on offset of the zio request modulo the number of members in the mirror. It assumes the devices are of equal performance and that spreading the requests randomly over both drives will be sufficient to saturate them. In practice this results in the leaf vdevs being under utilized. The new algorithm takes into the following additional factors: * Load of the vdevs (number outstanding I/O requests) * The locality of last queued I/O vs the new I/O request. Within the locality calculation additional knowledge about the underlying vdev is considered such as; is the device backing the vdev a rotating media device. This results in performance increases across the board as well as significant increases for predominantly streaming loads and for configurations which don't have evenly performing devices. The following are results from a setup with 3 Way Mirror with 2 x HD's and 1 x SSD from a basic test running multiple parrallel dd's. With pre-fetch disabled (vfs.zfs.prefetch_disable=1): == Stripe Balanced (default) == Read 15360MB using bs: 1048576, readers: 3, took 161 seconds @ 95 MB/s == Load Balanced (zfslinux) == Read 15360MB using bs: 1048576, readers: 3, took 297 seconds @ 51 MB/s == Load Balanced (locality freebsd) == Read 15360MB using bs: 1048576, readers: 3, took 54 seconds @ 284 MB/s With pre-fetch enabled (vfs.zfs.prefetch_disable=0): == Stripe Balanced (default) == Read 15360MB using bs: 1048576, readers: 3, took 91 seconds @ 168 MB/s == Load Balanced (zfslinux) == Read 15360MB using bs: 1048576, readers: 3, took 108 seconds @ 142 MB/s == Load Balanced (locality freebsd) == Read 15360MB using bs: 1048576, readers: 3, took 48 seconds @ 320 MB/s In addition to the performance changes the code was also restructured, with the help of Justin Gibbs, to provide a more logical flow which also ensures vdevs loads are only calculated from the set of valid candidates. The following additional sysctls where added to allow the administrator to tune the behaviour of the load algorithm: * vfs.zfs.vdev.mirror.rotating_inc * vfs.zfs.vdev.mirror.rotating_seek_inc * vfs.zfs.vdev.mirror.rotating_seek_offset * vfs.zfs.vdev.mirror.non_rotating_inc * vfs.zfs.vdev.mirror.non_rotating_seek_inc These changes where based on work started by the zfsonlinux developers: https://github.com/zfsonlinux/zfs/pull/1487 Reviewed by: gibbs, mav, will MFC after: 2 weeks Sponsored by: Multiplay References: https://github.com/freebsd/freebsd@5c7a6f5d https://github.com/freebsd/freebsd@31b7f68d https://github.com/freebsd/freebsd@e186f564 Performance Testing: https://github.com/zfsonlinux/zfs/pull/4334#issuecomment-189057141 Porting notes: - The tunables were adjusted to have ZoL-style names. - The code was modified to use ZoL's vd_nonrot. - Fixes were done to make cstyle.pl happy - Merge conflicts were handled manually - freebsd/freebsd@e186f564bc946f82c76e0b34c2f0370ed9aea022 by my collegue Andriy Gapon has been included. It applied perfectly, but added a cstyle regression. - This replaces 556011dbec2d10579819078559a77630fc559112 entirely. - A typo "IO'a" has been corrected to say "IO's" - Descriptions of new tunables were added to man/man5/zfs-module-parameters.5. Ported-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #4334
* Fix zfs_vdev_aggregation_limit bounds checkingBrian Behlendorf2015-12-181-11/+8
| | | | | | | | | | | | | Update the bounds checking for zfs_vdev_aggregation_limit so that it has a floor of zero and a maximum value of the supported block size for the pool. Additionally add an early return when zfs_vdev_aggregation_limit equals zero to disable aggregation. For very fast solid state or memory devices it may be more expensive to perform the aggregation than to issue the IO immediately. Signed-off-by: Brian Behlendorf <[email protected]>
* Fix vdev_queue_aggregate() deadlockBrian Behlendorf2015-12-181-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This deadlock may manifest itself in slightly different ways but at the core it is caused by a memory allocation blocking on file- system reclaim in the zio pipeline. This is normally impossible because zio_execute() disables filesystem reclaim by setting PF_FSTRANS on the thread. However, kmem cache allocations may still indirectly block on file system reclaim while holding the critical vq->vq_lock as shown below. To resolve this issue zio_buf_alloc_flags() is introduced which allocation flags to be passed. This can then be used in vdev_queue_aggregate() with KM_NOSLEEP when allocating the aggregate IO buffer. Since aggregating the IO is purely a performance optimization we want this to either succeed or fail quickly. Trying too hard to allocate this memory under the vq->vq_lock can negatively impact performance and result in this deadlock. * z_wr_iss zio_vdev_io_start vdev_queue_io -> Takes vq->vq_lock vdev_queue_io_to_issue vdev_queue_aggregate zio_buf_alloc -> Waiting on spl_kmem_cache process * z_wr_int zio_vdev_io_done vdev_queue_io_done mutex_lock -> Waiting on vq->vq_lock held by z_wr_iss * txg_sync spa_sync dsl_pool_sync zio_wait -> Waiting on zio being handled by z_wr_int * spl_kmem_cache spl_cache_grow_work kv_alloc spl_vmalloc ... evict zpl_evict_inode zfs_inactive dmu_tx_wait txg_wait_open -> Waiting on txg_sync Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Tim Chase <[email protected]> Closes #3808 Closes #3867
* Fix small typololi10K2015-08-301-1/+1
| | | | | | | | | | Add a missing space to the zfs_vdev_sync_write_min_active module parameter description. Signed-off-by: loli10K <[email protected]> Signed-off-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #3714
* Initialize the taskq entry embedded within struct vdevTim Chase2015-08-301-0/+1
| | | | | | | | | | | | | As part of the stack reduction effort in 50b25b2187134ac7b19cf93bd35a420223f1d343, a zio_t containing a taskq_ent was added to struct vdev_queue which itself is part of struct vdev. The taskq entry should be initialized as is currently done in zio_create() for newly-created bare zio_t object. The rationale is the same as is described in f467b05a265abcfb8e5a3269f79d08f36a58646a. Signed-off-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #3709
* Illumos 5027 - zfs large block supportMatthew Ahrens2015-05-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 5027 zfs large block support Reviewed by: Alek Pinchuk <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Josef 'Jeff' Sipek <[email protected]> Reviewed by: Richard Elling <[email protected]> Reviewed by: Saso Kiselkov <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Dan McDonald <[email protected]> References: https://www.illumos.org/issues/5027 https://github.com/illumos/illumos-gate/commit/b515258 Porting Notes: * Included in this patch is a tiny ISP2() cleanup in zio_init() from Illumos 5255. * Unlike the upstream Illumos commit this patch does not impose an arbitrary 128K block size limit on volumes. Volumes, like filesystems, are limited by the zfs_max_recordsize=1M module option. * By default the maximum record size is limited to 1M by the module option zfs_max_recordsize. This value may be safely increased up to 16M which is the largest block size supported by the on-disk format. At the moment, 1M blocks clearly offer a significant performance improvement but the benefits of going beyond this for the majority of workloads are less clear. * The illumos version of this patch increased DMU_MAX_ACCESS to 32M. This was determined not to be large enough when using 16M blocks because the zfs_make_xattrdir() function will fail (EFBIG) when assigning a TX. This was immediately observed under Linux because all newly created files must have a security xattr created and that was failing. Therefore, we've set DMU_MAX_ACCESS to 64M. * On 32-bit platforms a hard limit of 1M is set for blocks due to the limited virtual address space. We should be able to relax this one the ABD patches are merged. Ported-by: Brian Behlendorf <[email protected]> Closes #354
* 5313 Allow I/Os to be aggregated across ZIO priority classesJustin T. Gibbs2015-04-241-31/+48
| | | | | | | | | | | | | | | | Reviewed by: Andriy Gapon <[email protected]> Reviewed by: Will Andrews <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Approved by: Robert Mustacchi <[email protected]> References: https://www.illumos.org/issues/5313 https://github.com/illumos/illumos-gate/commit/fe319232 Ported-by: DHE <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #3280
* Revert "Pre-allocate vdev I/O buffers"Brian Behlendorf2015-01-161-41/+2
| | | | | | | | | | | | | | Commit 86dd0fd added preallocated I/O buffers. This is no longer required after the recent kmem changes designed to make our memory allocation interfaces behave more like those found on Illumos. A deadlock in this situation is no longer possible. However, these allocations still have the potential to be expensive. So a potential future optimization might be to perform then KM_NOSLEEP so that they either succeed of fail quicky. Either case is acceptable here because we can safely abort the aggregation. Signed-off-by: Brian Behlendorf <[email protected]>
* Illumos 4753 - increase number of outstanding async writes when sync task is ↵Alex Reece2014-09-231-4/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | waiting Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Adam Leventhal <[email protected]> Reviewed by: Christopher Siden <[email protected]> Reviewed by: Dan McDonald <[email protected]> Approved by: Garrett D'Amore <[email protected]> References: https://www.illumos.org/issues/4753 https://github.com/illumos/illumos-gate/commit/73527f4 Comments by Matt Ahrens from the issue tracker: When a sync task is waiting for a txg to complete, we should hurry it along by increasing the number of outstanding async writes (i.e. make vdev_queue_max_async_writes() return a larger number). Initially we might just have a tunable for "minimum async writes while a synctask is waiting" and set it to 3. Ported-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #2716
* Avoid dynamic allocation of 'search zio'Brian Behlendorf2014-08-111-6/+4
| | | | | | | | | | | | | | | | As part of commit e8b96c6 the search zio used by the vdev_queue_io_to_issue() function was moved to the heap to minimize stack usage. Functionally this is fine, but to maximize performance it's best to minimize the number of dynamic allocations. To avoid this allocation temporary space for the search zio has been reserved in the vdev_queue structure. All access must be serialized through the vq_lock. Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Ned Bass <[email protected]> Closes #2572
* cstyle: Resolve C style issuesMichael Kjorling2013-12-181-14/+16
| | | | | | | | | | | | | | | | | | The vast majority of these changes are in Linux specific code. They are the result of not having an automated style checker to validate the code when it was originally written. Others were caused when the common code was slightly adjusted for Linux. This patch contains no functional changes. It only refreshes the code to conform to style guide. Everyone submitting patches for inclusion upstream should now run 'make checkstyle' and resolve any warning prior to opening a pull request. The automated builders have been updated to fail a build if when 'make checkstyle' detects an issue. Signed-off-by: Brian Behlendorf <[email protected]> Closes #1821
* Illumos #4045 write throttle & i/o scheduler performance workMatthew Ahrens2013-12-061-212/+522
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 4045 zfs write throttle & i/o scheduler performance work 1. The ZFS i/o scheduler (vdev_queue.c) now divides i/os into 5 classes: sync read, sync write, async read, async write, and scrub/resilver. The scheduler issues a number of concurrent i/os from each class to the device. Once a class has been selected, an i/o is selected from this class using either an elevator algorithem (async, scrub classes) or FIFO (sync classes). The number of concurrent async write i/os is tuned dynamically based on i/o load, to achieve good sync i/o latency when there is not a high load of writes, and good write throughput when there is. See the block comment in vdev_queue.c (reproduced below) for more details. 2. The write throttle (dsl_pool_tempreserve_space() and txg_constrain_throughput()) is rewritten to produce much more consistent delays when under constant load. The new write throttle is based on the amount of dirty data, rather than guesses about future performance of the system. When there is a lot of dirty data, each transaction (e.g. write() syscall) will be delayed by the same small amount. This eliminates the "brick wall of wait" that the old write throttle could hit, causing all transactions to wait several seconds until the next txg opens. One of the keys to the new write throttle is decrementing the amount of dirty data as i/o completes, rather than at the end of spa_sync(). Note that the write throttle is only applied once the i/o scheduler is issuing the maximum number of outstanding async writes. See the block comments in dsl_pool.c and above dmu_tx_delay() (reproduced below) for more details. This diff has several other effects, including: * the commonly-tuned global variable zfs_vdev_max_pending has been removed; use per-class zfs_vdev_*_max_active values or zfs_vdev_max_active instead. * the size of each txg (meaning the amount of dirty data written, and thus the time it takes to write out) is now controlled differently. There is no longer an explicit time goal; the primary determinant is amount of dirty data. Systems that are under light or medium load will now often see that a txg is always syncing, but the impact to performance (e.g. read latency) is minimal. Tune zfs_dirty_data_max and zfs_dirty_data_sync to control this. * zio_taskq_batch_pct = 75 -- Only use 75% of all CPUs for compression, checksum, etc. This improves latency by not allowing these CPU-intensive tasks to consume all CPU (on machines with at least 4 CPU's; the percentage is rounded up). --matt APPENDIX: problems with the current i/o scheduler The current ZFS i/o scheduler (vdev_queue.c) is deadline based. The problem with this is that if there are always i/os pending, then certain classes of i/os can see very long delays. For example, if there are always synchronous reads outstanding, then no async writes will be serviced until they become "past due". One symptom of this situation is that each pass of the txg sync takes at least several seconds (typically 3 seconds). If many i/os become "past due" (their deadline is in the past), then we must service all of these overdue i/os before any new i/os. This happens when we enqueue a batch of async writes for the txg sync, with deadlines 2.5 seconds in the future. If we can't complete all the i/os in 2.5 seconds (e.g. because there were always reads pending), then these i/os will become past due. Now we must service all the "async" writes (which could be hundreds of megabytes) before we service any reads, introducing considerable latency to synchronous i/os (reads or ZIL writes). Notes on porting to ZFS on Linux: - zio_t gained new members io_physdone and io_phys_children. Because object caches in the Linux port call the constructor only once at allocation time, objects may contain residual data when retrieved from the cache. Therefore zio_create() was updated to zero out the two new fields. - vdev_mirror_pending() relied on the depth of the per-vdev pending queue (vq->vq_pending_tree) to select the least-busy leaf vdev to read from. This tree has been replaced by vq->vq_active_tree which is now used for the same purpose. - vdev_queue_init() used the value of zfs_vdev_max_pending to determine the number of vdev I/O buffers to pre-allocate. That global no longer exists, so we instead use the sum of the *_max_active values for each of the five I/O classes described above. - The Illumos implementation of dmu_tx_delay() delays a transaction by sleeping in condition variable embedded in the thread (curthread->t_delay_cv). We do not have an equivalent CV to use in Linux, so this change replaced the delay logic with a wrapper called zfs_sleep_until(). This wrapper could be adopted upstream and in other downstream ports to abstract away operating system-specific delay logic. - These tunables are added as module parameters, and descriptions added to the zfs-module-parameters.5 man page. spa_asize_inflation zfs_deadman_synctime_ms zfs_vdev_max_active zfs_vdev_async_write_active_min_dirty_percent zfs_vdev_async_write_active_max_dirty_percent zfs_vdev_async_read_max_active zfs_vdev_async_read_min_active zfs_vdev_async_write_max_active zfs_vdev_async_write_min_active zfs_vdev_scrub_max_active zfs_vdev_scrub_min_active zfs_vdev_sync_read_max_active zfs_vdev_sync_read_min_active zfs_vdev_sync_write_max_active zfs_vdev_sync_write_min_active zfs_dirty_data_max_percent zfs_delay_min_dirty_percent zfs_dirty_data_max_max_percent zfs_dirty_data_max zfs_dirty_data_max_max zfs_dirty_data_sync zfs_delay_scale The latter four have type unsigned long, whereas they are uint64_t in Illumos. This accommodates Linux's module_param() supported types, but means they may overflow on 32-bit architectures. The values zfs_dirty_data_max and zfs_dirty_data_max_max are the most likely to overflow on 32-bit systems, since they express physical RAM sizes in bytes. In fact, Illumos initializes zfs_dirty_data_max_max to 2^32 which does overflow. To resolve that, this port instead initializes it in arc_init() to 25% of physical RAM, and adds the tunable zfs_dirty_data_max_max_percent to override that percentage. While this solution doesn't completely avoid the overflow issue, it should be a reasonable default for most systems, and the minority of affected systems can work around the issue by overriding the defaults. - Fixed reversed logic in comment above zfs_delay_scale declaration. - Clarified comments in vdev_queue.c regarding when per-queue minimums take effect. - Replaced dmu_tx_write_limit in the dmu_tx kstat file with dmu_tx_dirty_delay and dmu_tx_dirty_over_max. The first counts how many times a transaction has been delayed because the pool dirty data has exceeded zfs_delay_min_dirty_percent. The latter counts how many times the pool dirty data has exceeded zfs_dirty_data_max (which we expect to never happen). - The original patch would have regressed the bug fixed in zfsonlinux/zfs@c418410, which prevented users from setting the zfs_vdev_aggregation_limit tuning larger than SPA_MAXBLOCKSIZE. A similar fix is added to vdev_queue_aggregate(). - In vdev_queue_io_to_issue(), dynamically allocate 'zio_t search' on the heap instead of the stack. In Linux we can't afford such large structures on the stack. Reviewed by: George Wilson <[email protected]> Reviewed by: Adam Leventhal <[email protected]> Reviewed by: Christopher Siden <[email protected]> Reviewed by: Ned Bass <[email protected]> Reviewed by: Brendan Gregg <[email protected]> Approved by: Robert Mustacchi <[email protected]> References: http://www.illumos.org/issues/4045 illumos/illumos-gate@69962b5647e4a8b9b14998733b765925381b727e Ported-by: Ned Bass <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #1913
* Illumos #3742Will Andrews2013-11-041-5/+6
| | | | | | | | | | | | | | | | | | | | | 3742 zfs comments need cleaner, more consistent style Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Eric Schrock <[email protected]> Approved by: Christopher Siden <[email protected]> References: https://www.illumos.org/issues/3742 illumos/illumos-gate@f7170741490edba9d1d9c697c177c887172bc741 Ported-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #1775 Porting notes: 1. The change to zfs_vfsops.c was dropped because it involves zfs_mount_label_policy, which does not exist in the Linux port.
* Illumos #3537Matthew Ahrens2013-10-311-3/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 3537 want pool io kstats Reviewed by: George Wilson <[email protected]> Reviewed by: Adam Leventhal <[email protected]> Reviewed by: Eric Schrock <[email protected]> Reviewed by: Sa?o Kiselkov <[email protected]> Reviewed by: Garrett D'Amore <[email protected]> Reviewed by: Brendan Gregg <[email protected]> Approved by: Gordon Ross <[email protected]> References: http://www.illumos.org/issues/3537 illumos/illumos-gate@c3a6601 Ported by: Cyril Plisko <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Porting Notes: 1. The patch was restructured to take advantage of the existing spa statistics infrastructure. To accomplish this the kstat was moved in to spa->io_stats and the init/destroy code moved to spa_stats.c. 2. The I/O kstat was simply named <pool> which conflicted with the pool directory we had already created. Therefore it was renamed to <pool>/io 3. An update handler was added to allow the kstat to be zeroed.
* Illumos #3618 ::zio dcmd does not show timestamp dataMatthew Ahrens2013-08-121-5/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 3618 ::zio dcmd does not show timestamp data Reviewed by: Adam Leventhal <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Christopher Siden <[email protected]> Reviewed by: Garrett D'Amore <[email protected]> Approved by: Dan McDonald <[email protected]> References: http://www.illumos.org/issues/3618 illumos/illumos-gate@c55e05cb35da47582b7afd38734d2f0d9c6deb40 Notes on porting to ZFS on Linux: The original changeset mostly deals with mdb ::zio dcmd. However, in order to provide the requested functionality it modifies vdev and zio structures to keep the timing data in nanoseconds instead of ticks. It is these changes that are ported over in the commit in hand. One visible change of this commit is that the default value of 'zfs_vdev_time_shift' tunable is changed: zfs_vdev_time_shift = 6 to zfs_vdev_time_shift = 29 The original value of 6 was inherited from OpenSolaris and was subotimal - since it shifted the raw tick value - it didn't compensate for different tick frequencies on Linux and OpenSolaris. The former has HZ=1000, while the latter HZ=100. (Which itself led to other interesting performance anomalies under non-trivial load. The deadline scheduler delays the IO according to its priority - the lower priority the further the deadline is set. The delay is measured in units of "shifted ticks". Since the HZ value was 10 times higher, the delay units were 10 times shorter. Thus really low priority IO like resilver (delay is 10 units) and scrub (delay is 20 units) were scheduled much sooner than intended. The overall effect is that resilver and scrub IO consumed more bandwidth at the expense of the other IO.) Now that the bookkeeping is done is nanoseconds the shift behaves correctly for any tick frequency (HZ). Ported-by: Cyril Plisko <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #1643
* 3246 ZFS I/O deadman threadGeorge.Wilson2013-05-011-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Eric Schrock <[email protected]> Reviewed by: Christopher Siden <[email protected]> Approved by: Garrett D'Amore <[email protected]> NOTES: This patch has been reworked from the original in the following ways to accomidate Linux ZFS implementation *) Usage of the cyclic interface was replaced by the delayed taskq interface. This avoids the need to implement new compatibility code and allows us to rely on the existing taskq implementation. *) An extern for zfs_txg_synctime_ms was added to sys/dsl_pool.h because declaring externs in source files as was done in the original patch is just plain wrong. *) Instead of panicing the system when the deadman triggers a zevent describing the blocked vdev and the first pending I/O is posted. If the panic behavior is desired Linux provides other generic methods to panic the system when threads are observed to hang. *) For reference, to delay zios by 30 seconds for testing you can use zinject as follows: 'zinject -d <vdev> -D30 <pool>' References: illumos/illumos-gate@283b84606b6fc326692c03273de1774e8c122f9a https://www.illumos.org/issues/3246 Ported-by: Brian Behlendorf <[email protected]> Closes #1396
* Limit zfs_vdev_aggregation_limit to SPA_MAXBLOCKSIZEBrian Behlendorf2012-10-151-2/+2
| | | | | | | | Prevent users from setting the zfs_vdev_aggregation_limit tuning larger than SPA_MAXBLOCKSIZE. Signed-off-by: Brian Behlendorf <[email protected]> Closes #520
* Pre-allocate vdev I/O buffersBrian Behlendorf2012-08-271-2/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The vdev queue layer may require a small number of buffers when attempting to create aggregate I/O requests. Rather than attempting to allocate them from the global zio buffers, which is slow under memory pressure, it makes sense to pre-allocate them because... 1) These buffers are short lived. They are only required for the life of a single I/O at which point they can be used by the next I/O. 2) The maximum number of concurrent buffers needed by a vdev is small. It's roughly limited by the zfs_vdev_max_pending tunable which defaults to 10. By keeping a small list of these buffer per-vdev we can ensure one is always available when we need it. This significantly reduces contention on the vq->vq_lock, because we no longer need to perform a slow allocation under this lock. This is particularly important when memory is already low on the system. It would probably be wise to extend the use of these buffers beyond aggregate I/O and in to the raidz implementation. The inability to quickly allocate buffer for the parity stripes could result in similiar problems. Signed-off-by: Brian Behlendorf <[email protected]>
* Add missing ZFS tunablesBrian Behlendorf2011-05-041-3/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit adds module options for all existing zfs tunables. Ideally the average user should never need to modify any of these values. However, in practice sometimes you do need to tweak these values for one reason or another. In those cases it's nice not to have to resort to rebuilding from source. All tunables are visable to modinfo and the list is as follows: $ modinfo module/zfs/zfs.ko filename: module/zfs/zfs.ko license: CDDL author: Sun Microsystems/Oracle, Lawrence Livermore National Laboratory description: ZFS srcversion: 8EAB1D71DACE05B5AA61567 depends: spl,znvpair,zcommon,zunicode,zavl vermagic: 2.6.32-131.0.5.el6.x86_64 SMP mod_unload modversions parm: zvol_major:Major number for zvol device (uint) parm: zvol_threads:Number of threads for zvol device (uint) parm: zio_injection_enabled:Enable fault injection (int) parm: zio_bulk_flags:Additional flags to pass to bulk buffers (int) parm: zio_delay_max:Max zio millisec delay before posting event (int) parm: zio_requeue_io_start_cut_in_line:Prioritize requeued I/O (bool) parm: zil_replay_disable:Disable intent logging replay (int) parm: zfs_nocacheflush:Disable cache flushes (bool) parm: zfs_read_chunk_size:Bytes to read per chunk (long) parm: zfs_vdev_max_pending:Max pending per-vdev I/Os (int) parm: zfs_vdev_min_pending:Min pending per-vdev I/Os (int) parm: zfs_vdev_aggregation_limit:Max vdev I/O aggregation size (int) parm: zfs_vdev_time_shift:Deadline time shift for vdev I/O (int) parm: zfs_vdev_ramp_rate:Exponential I/O issue ramp-up rate (int) parm: zfs_vdev_read_gap_limit:Aggregate read I/O over gap (int) parm: zfs_vdev_write_gap_limit:Aggregate write I/O over gap (int) parm: zfs_vdev_scheduler:I/O scheduler (charp) parm: zfs_vdev_cache_max:Inflate reads small than max (int) parm: zfs_vdev_cache_size:Total size of the per-disk cache (int) parm: zfs_vdev_cache_bshift:Shift size to inflate reads too (int) parm: zfs_scrub_limit:Max scrub/resilver I/O per leaf vdev (int) parm: zfs_recover:Set to attempt to recover from fatal errors (int) parm: spa_config_path:SPA config file (/etc/zfs/zpool.cache) (charp) parm: zfs_zevent_len_max:Max event queue length (int) parm: zfs_zevent_cols:Max event column width (int) parm: zfs_zevent_console:Log events to the console (int) parm: zfs_top_maxinflight:Max I/Os per top-level (int) parm: zfs_resilver_delay:Number of ticks to delay resilver (int) parm: zfs_scrub_delay:Number of ticks to delay scrub (int) parm: zfs_scan_idle:Idle window in clock ticks (int) parm: zfs_scan_min_time_ms:Min millisecs to scrub per txg (int) parm: zfs_free_min_time_ms:Min millisecs to free per txg (int) parm: zfs_resilver_min_time_ms:Min millisecs to resilver per txg (int) parm: zfs_no_scrub_io:Set to disable scrub I/O (bool) parm: zfs_no_scrub_prefetch:Set to disable scrub prefetching (bool) parm: zfs_txg_timeout:Max seconds worth of delta per txg (int) parm: zfs_no_write_throttle:Disable write throttling (int) parm: zfs_write_limit_shift:log2(fraction of memory) per txg (int) parm: zfs_txg_synctime_ms:Target milliseconds between tgx sync (int) parm: zfs_write_limit_min:Min tgx write limit (ulong) parm: zfs_write_limit_max:Max tgx write limit (ulong) parm: zfs_write_limit_inflated:Inflated tgx write limit (ulong) parm: zfs_write_limit_override:Override tgx write limit (ulong) parm: zfs_prefetch_disable:Disable all ZFS prefetching (int) parm: zfetch_max_streams:Max number of streams per zfetch (uint) parm: zfetch_min_sec_reap:Min time before stream reclaim (uint) parm: zfetch_block_cap:Max number of blocks to fetch at a time (uint) parm: zfetch_array_rd_sz:Number of bytes in a array_read (ulong) parm: zfs_pd_blks_max:Max number of blocks to prefetch (int) parm: zfs_dedup_prefetch:Enable prefetching dedup-ed blks (int) parm: zfs_arc_min:Min arc size (ulong) parm: zfs_arc_max:Max arc size (ulong) parm: zfs_arc_meta_limit:Meta limit for arc size (ulong) parm: zfs_arc_reduce_dnlc_percent:Meta reclaim percentage (int) parm: zfs_arc_grow_retry:Seconds before growing arc size (int) parm: zfs_arc_shrink_shift:log2(fraction of arc to reclaim) (int) parm: zfs_arc_p_min_shift:arc_c shift to calc min/max arc_p (int)
* Add linux kernel module supportBrian Behlendorf2010-08-311-0/+11
| | | | | | | | | | | Setup linux kernel module support, this includes: - zfs context for kernel/user - kernel module build system integration - kernel module macros - kernel module symbol export - kernel module options Signed-off-by: Brian Behlendorf <[email protected]>
* Fix gcc c90 compliance warningsBrian Behlendorf2010-08-271-1/+2
| | | | | | | | Fix non-c90 compliant code, for the most part these changes simply deal with where a particular variable is declared. Under c90 it must alway be done at the very start of a block. Signed-off-by: Brian Behlendorf <[email protected]>
* Update core ZFS code from build 121 to build 141.Brian Behlendorf2010-05-281-5/+5
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* Rebase master to b121Brian Behlendorf2009-08-181-12/+103
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