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* Change os->os_next_write_raw to work per txgTom Caputi2018-02-021-0/+1
| | | | | | | | | | | | | | | | | | | Currently, os_next_write_raw is a single boolean used for determining whether or not the next call to dmu_objset_sync() should write out the objset_phys_t as a raw buffer. Since the boolean is not associated with a txg, the work simply happens during the next txg, which is not necessarily the correct one. In the current implementation this issue was misdiagnosed, resulting in a small hack in dmu_objset_sync() which seemed to resolve the problem. This patch changes os_next_write_raw to be an array of booleans, one for each txg in TXG_OFF and removes the hack. Reviewed-by: Jorgen Lundman <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #6864
* Add dbuf hash and dbuf cache kstatsGiuseppe Di Natale2018-01-291-14/+180
| | | | | | | | | | | | | | | | | | | | | | | Introduce kstats about the dbuf hash and dbuf cache to make it easier to inspect state. This should help with debugging and understanding of these portions of the codebase. Correct format of dbuf kstat file. Introduce a dbc column to dbufs kstat to indicate if a dbuf is in the dbuf cache. Introduce field filtering in the dbufstat python script. Introduce a no header option to the dbufstat python script. Introduce a test case to test basic mru->mfu list movement in the ARC. Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Giuseppe Di Natale <[email protected]> Closes #6906
* Fix ARC hit rateBrian Behlendorf2018-01-081-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | When the compressed ARC feature was added in commit d3c2ae1 the method of reference counting in the ARC was modified. As part of this accounting change the arc_buf_add_ref() function was removed entirely. This would have be fine but the arc_buf_add_ref() function served a second undocumented purpose of updating the ARC access information when taking a hold on a dbuf. Without this logic in place a cached dbuf would not migrate its associated arc_buf_hdr_t to the MFU list. This would negatively impact the ARC hit rate, particularly on systems with a small ARC. This change reinstates the missing call to arc_access() from dbuf_hold() by implementing a new arc_buf_access() function. Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Tim Chase <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #6171 Closes #6852 Closes #6989
* Sequential scrub and resilversTom Caputi2017-11-151-6/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* OpenZFS 7531 - Assign correct flags to prefetched buffersbenrubson2017-11-111-0/+12
| | | | | | | | | | | Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Prakash Surya <[email protected]> Authored by: abraunegg <[email protected]> Approved by: Dan McDonald <[email protected]> Ported-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7531 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/468008cb
* Handle compressed buffers in __dbuf_hold_impl()Tim Chase2017-11-081-12/+43
| | | | | | | | | | | | | | | | | | | | | | | | | | | In __dbuf_hold_impl(), if a buffer is currently syncing and is still referenced from db_data, a copy is made in case it is dirtied again in the txg. Previously, the buffer for the copy was simply allocated with arc_alloc_buf() which doesn't handle compressed or encrypted buffers (which are a special case of a compressed buffer). The result was typically an invalid memory access because the newly-allocated buffer was of the uncompressed size. This commit fixes the problem by handling the 2 compressed cases, encrypted and unencrypted, respectively, with arc_alloc_raw_buf() and arc_alloc_compressed_buf(). Although using the proper allocation functions fixes the invalid memory access by allocating a buffer of the compressed size, another unrelated issue made it impossible to properly detect compressed buffers in the first place. The header's compression flag was set to ZIO_COMPRESS_OFF in arc_write() when it was possible that an attached buffer was actually compressed. This commit adds logic to only set ZIO_COMPRESS_OFF in the non-ZIO_RAW case which wil handle both cases of compressed buffers (encrypted or unencrypted). Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Tim Chase <[email protected]> Closes #5742 Closes #6797
* Undo c89 workarounds to match with upstreamDon Brady2017-11-041-26/+16
| | | | | | | | | 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
* OpenZFS 8081 - Compiler warnings in zdbBrian Behlendorf2017-10-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix compiler warnings in zdb. With these changes, FreeBSD can compile zdb with all compiler warnings enabled save -Wunused-parameter. usr/src/cmd/zdb/zdb.c usr/src/cmd/zdb/zdb_il.c usr/src/uts/common/fs/zfs/sys/sa.h usr/src/uts/common/fs/zfs/sys/spa.h Fix numerous warnings, including: * const-correctness * shadowing global definitions * signed vs unsigned comparisons * missing prototypes, or missing static declarations * unused variables and functions * Unreadable array initializations * Missing struct initializers usr/src/cmd/zdb/zdb.h Add a header file to declare common symbols usr/src/lib/libzpool/common/sys/zfs_context.h usr/src/uts/common/fs/zfs/arc.c usr/src/uts/common/fs/zfs/dbuf.c usr/src/uts/common/fs/zfs/spa.c usr/src/uts/common/fs/zfs/txg.c Add a function prototype for zk_thread_create, and ensure that every callback supplied to this function actually matches the prototype. usr/src/cmd/ztest/ztest.c usr/src/uts/common/fs/zfs/sys/zil.h usr/src/uts/common/fs/zfs/zfs_replay.c usr/src/uts/common/fs/zfs/zvol.c Add a function prototype for zil_replay_func_t, and ensure that every function of this type actually matches the prototype. usr/src/uts/common/fs/zfs/sys/refcount.h Change FTAG so it discards any constness of __func__, necessary since existing APIs expect it passed as void *. Porting Notes: - Many of these fixes have already been applied to Linux. For consistency the OpenZFS version of a change was applied if the warning was addressed in an equivalent but different fashion. Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Prakash Surya <[email protected]> Authored by: Alan Somers <[email protected]> Approved by: Richard Lowe <[email protected]> Ported-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/8081 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/843abe1b8a Closes #6787
* Fixes for #6639Tom Caputi2017-10-111-0/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Several issues were uncovered by running stress tests with zfs encryption and raw sends in particular. The issues and their associated fixes are as follows: * arc_read_done() has the ability to chain several requests for the same block of data via the arc_callback_t struct. In these cases, the ARC would only use the first request's dsobj from the bookmark to decrypt the data. This is problematic because the first request might be a prefetch zio which is able to handle the key not being loaded, while the second might use a different key that it is sure will work. The fix here is to pass the dsobj with each individual arc_callback_t so that each request can attempt to decrypt the data separately. * DRR_FREE and DRR_FREEOBJECT records in a send file were not having their transactions properly tagged as raw during raw sends, which caused a panic when the dbuf code attempted to decrypt these blocks. * traverse_prefetch_metadata() did not properly set ZIO_FLAG_SPECULATIVE when issuing prefetch IOs. * Added a few asserts and code cleanups to ensure these issues are more detectable in the future. Signed-off-by: Tom Caputi <[email protected]>
* Encryption patch follow-upTom Caputi2017-10-111-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | * PBKDF2 implementation changed to OpenSSL implementation. * HKDF implementation moved to its own file and tests added to ensure correctness. * Removed libzfs's now unnecessary dependency on libzpool and libicp. * Ztest can now create and test encrypted datasets. This is currently disabled until issue #6526 is resolved, but otherwise functions as advertised. * Several small bug fixes discovered after enabling ztest to run on encrypted datasets. * Fixed coverity defects added by the encryption patch. * Updated man pages for encrypted send / receive behavior. * Fixed a bug where encrypted datasets could receive DRR_WRITE_EMBEDDED records. * Minor code cleanups / consolidation. Signed-off-by: Tom Caputi <[email protected]>
* Scale the dbuf cache with arc_cchrisrd2017-09-291-6/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | Commit d3c2ae1 introduced a dbuf cache with a default size of the minimum of 100M or 1/32 maximum ARC size. (These figures may be adjusted using dbuf_cache_max_bytes and dbuf_cache_max_shift.) The dbuf cache is counted as metadata for the purposes of ARC size calculations. On a 1GB box the ARC maximum size defaults to c_max 493M which gives a dbuf cache default minimum size of 15.4M, and the ARC metadata defaults to minimum 16M. I.e. the dbuf cache is an significant proportion of the minimum metadata size. With other overheads involved this actually means the ARC metadata doesn't get down to the minimum. This patch dynamically scales the dbuf cache to the target ARC size instead of statically scaling it to the maximum ARC size. (The scale is still set by dbuf_cache_max_shift and the maximum size is still fixed by dbuf_cache_max_bytes.) Using the target ARC size rather than the current ARC size is done to help the ARC reach the target rather than simply focusing on the current size. Reviewed-by: Chunwei Chen <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Chris Dunlop <[email protected]> Issue #6506 Closes #6561
* dbuf_cons: deduplicate multilist_link_init()chrisrd2017-08-241-1/+0
| | | | | | | | | | | Remove harmless duplicate multilist_link_init() introduced by commit d3c2ae1. Reviewed-by: George Melikov <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: loli10K <[email protected]> Signed-off-by: Chris Dunlop <[email protected]> Closes #6552
* Native Encryption for ZFS on LinuxTom Caputi2017-08-141-36/+173
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change incorporates three major pieces: The first change is a keystore that manages wrapping and encryption keys for encrypted datasets. These commands mostly involve manipulating the new DSL Crypto Key ZAP Objects that live in the MOS. Each encrypted dataset has its own DSL Crypto Key that is protected with a user's key. This level of indirection allows users to change their keys without re-encrypting their entire datasets. The change implements the new subcommands "zfs load-key", "zfs unload-key" and "zfs change-key" which allow the user to manage their encryption keys and settings. In addition, several new flags and properties have been added to allow dataset creation and to make mounting and unmounting more convenient. The second piece of this patch provides the ability to encrypt, decyrpt, and authenticate protected datasets. Each object set maintains a Merkel tree of Message Authentication Codes that protect the lower layers, similarly to how checksums are maintained. This part impacts the zio layer, which handles the actual encryption and generation of MACs, as well as the ARC and DMU, which need to be able to handle encrypted buffers and protected data. The last addition is the ability to do raw, encrypted sends and receives. The idea here is to send raw encrypted and compressed data and receive it exactly as is on a backup system. This means that the dataset on the receiving system is protected using the same user key that is in use on the sending side. By doing so, datasets can be efficiently backed up to an untrusted system without fear of data being compromised. Reviewed by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Jorgen Lundman <[email protected]> Signed-off-by: Tom Caputi <[email protected]> Closes #494 Closes #5769
* Simplify threads, mutexs, cvs and rwlocksBrian Behlendorf2017-08-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * Simplify threads, mutexs, cvs and rwlocks * Update the zk_thread_create() function to use the same trick as Illumos. Specifically, cast the new pthread_t to a void pointer and return that as the kthread_t *. This avoids the issues associated with managing a wrapper structure and is safe as long as the callers never attempt to dereference it. * Update all function prototypes passed to pthread_create() to match the expected prototype. We were getting away this with before since the function were explicitly cast. * Replaced direct zk_thread_create() calls with thread_create() for code consistency. All consumers of libzpool now use the proper wrappers. * The mutex_held() calls were converted to MUTEX_HELD(). * Removed all mutex_owner() calls and retired the interface. Instead use MUTEX_HELD() which provides the same information and allows the implementation details to be hidden. In this case the use of the pthread_equals() function. * The kthread_t, kmutex_t, krwlock_t, and krwlock_t types had any non essential fields removed. In the case of kthread_t and kcondvar_t they could be directly typedef'd to pthread_t and pthread_cond_t respectively. * Removed all extra ASSERTS from the thread, mutex, rwlock, and cv wrapper functions. In practice, pthreads already provides the vast majority of checks as long as we check the return code. Removing this code from our wrappers help readability. * Added TS_JOINABLE state flag to pass to request a joinable rather than detached thread. This isn't a standard thread_create() state but it's the least invasive way to pass this information and is only used by ztest. TEST_ZTEST_TIMEOUT=3600 Chunwei Chen <[email protected]> Reviewed-by: Tom Caputi <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #4547 Closes #5503 Closes #5523 Closes #6377 Closes #6495
* OpenZFS 8126 - ztest assertion failed in dbuf_dirty due to dn_nlevels changingMatthew Ahrens2017-07-071-5/+10
| | | | | | | | | | | | | | | | | | | The sync thread is concurrently modifying dn_phys->dn_nlevels while dbuf_dirty() is trying to assert something about it, without holding the necessary lock. We need to move this assertion further down in the function, after we have acquired the dn_struct_rwlock. Authored by: Matthew Ahrens <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Approved by: Robert Mustacchi <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: Giuseppe Di Natale <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/8126 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/0ef125d Closes #6314
* Clean up large dnode codeMatthew Ahrens2017-06-291-1/+2
| | | | | | | | | | | | Resolves issues discovered when porting to OpenZFS. * Lint warnings. * Made dnode_move_impl() large dnode aware. This functionality is currently unused on Linux. Reviewed-by: Ned Bass <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Matthew Ahrens <[email protected]> Closes #6262
* OpenZFS 8156 - dbuf_evict_notify() does not need dbuf_evict_lockMatthew Ahrens2017-06-091-11/+7
| | | | | | | | | | | | | | | | | | | | | Authored by: Matthew Ahrens <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Approved by: Robert Mustacchi <[email protected]> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: Giuseppe Di Natale <[email protected]> dbuf_evict_notify() holds the dbuf_evict_lock while checking if it should do the eviction itself (because the evict thread is not able to keep up). This can result in massive lock contention. It isn't necessary to hold the lock, because if we make the wrong choice occasionally, nothing bad will happen. This commit results in a ~60% performance improvement for ARC-cached sequential reads. OpenZFS-issue: https://www.illumos.org/issues/8156 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/f73e5d9 Closes #6204
* OpenZFS 8155 - simplify dmu_write_policy handling of pre-compressed buffersMatthew Ahrens2017-06-071-3/+1
| | | | | | | | | | | | | | | | | | | | | | | Authored by: Matthew Ahrens <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: George Wilson <[email protected]> Approved by: Robert Mustacchi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: Giuseppe Di Natale <[email protected]> When writing pre-compressed buffers, arc_write() requires that the compression algorithm used to compress the buffer matches the compression algorithm requested by the zio_prop_t, which is set by dmu_write_policy(). This makes dmu_write_policy() and its callers a bit more complicated. We simplify this by making arc_write() trust the caller to supply the type of pre-compressed buffer that it wants to write, and override the compression setting in the zio_prop_t. OpenZFS-issue: https://www.illumos.org/issues/8155 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/b55ff58 Closes #6200
* OpenZFS 8070 - Add some ZFS commentsAlan Somers2017-05-251-0/+5
| | | | | | | | | | | | | | Authored by: Alan Somers <[email protected]> Reviewed by: Yuri Pankov <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Approved by: Robert Mustacchi <[email protected]> Reviewed-by: Giuseppe Di Natale <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: bunder2015 <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/8070 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/40713f2 Closes #6160
* OpenZFS 7252 - compressed zfs send / receiveDan Kimmel2017-04-261-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | OpenZFS 7252 - compressed zfs send / receive OpenZFS 7628 - create long versions of ZFS send / receive options Authored by: Dan Kimmel <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: John Kennedy <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Sebastien Roy <[email protected]> Reviewed by: David Quigley <[email protected]> Reviewed by: Thomas Caputi <[email protected]> Approved by: Dan McDonald <[email protected]> Reviewed by: David Quigley <[email protected]> Reviewed-by: loli10K <[email protected]> Ported-by: bunder2015 <[email protected]> Ported-by: Don Brady <[email protected]> Ported-by: Brian Behlendorf <[email protected]> Porting Notes: - Most of 7252 was already picked up during ABD work. This commit represents the gap from the final commit to openzfs. - Fixed split_large_blocks check in do_dump() - An alternate version of the write_compressible() function was implemented for Linux which does not depend on fio. The behavior of fio differs significantly based on the exact version. - mkholes was replaced with truncate for Linux. OpenZFS-issue: https://www.illumos.org/issues/7252 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/5602294 Closes #6067
* OpenZFS 8025 - dbuf_read() creates unnecessary zio_root() for bonus bufMatthew Ahrens2017-04-241-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Authored by: Matthew Ahrens <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Prashanth Sreenivasa <[email protected]> Approved by: Robert Mustacchi <[email protected]> Ported-by: Brian Behlendorf <[email protected]> dbuf_read() creates a zio_root() to track and wait for all the zio's that may happen as part of this call. However, if the blkptr_t for this buffer is NULL or a hole, we will not create any more zio's, so this zio_root() is unnecessary. This is always the case when calling dbuf_read() on a bonus buffer, because it has no blkptr (it's part of the containing dnode). For workloads that read a lot of bonus buffers (e.g. file creation and removal), creating and destroying these unnecessary zio's can decrease performance by around 3%. The fix is to only create/destroy the zio_root() in dbuf_read() if the blkptr is not NULL and not a hole. Porting Notes: - The error handling for when dbuf_read_impl() fails which was originally added in commit 5f6d0b6f5 has been preserved. OpenZFS-issue: https://www.illumos.org/issues/8025 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/8ec5c7c Closes #6048
* OpenZFS 8023 - Panic destroying a metaslab deferred range treeGeorge Wilson2017-04-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | Authored by: George Wilson <[email protected]> Approved by: Dan McDonald <[email protected]> Reviewed by: Brad Lewis <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Saso Kiselkov <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Ported-by: Giuseppe Di Natale <[email protected]> We don't want to dirty any data when we're in the final txgs of the pool export logic. This change introduces checks to make sure that no data is dirtied after a certain point. It also addresses the culprit of this specific bug – the space map cannot be upgraded when we're in final stages of pool export. If we encounter a space map that wants to be upgraded in this phase, then we simply ignore the request as it will get retried the next time we set the fragmentation metric on that metaslab. OpenZFS-issue: https://www.illumos.org/issues/8023 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/2ef00f5 Closes #5991
* OpenZFS 7968 - multi-threaded spa_sync()Matthew Ahrens2017-03-201-9/+9
| | | | | | | | | | | | | | | | | | | | | | | Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Brad Lewis <[email protected]> Reviewed by: Saso Kiselkov <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Ported-by: Matthew Ahrens <[email protected]> spa_sync() iterates over all the dirty dnodes and processes each of them by calling dnode_sync(). If there are many dirty dnodes (e.g. because we created or removed a lot of files), the single thread of spa_sync() calling dnode_sync() can become a bottleneck. Additionally, if many dnodes are dirtied concurrently in open context (e.g. due to concurrent file creation), the os_lock will experience lock contention via dnode_setdirty(). The solution is to track dirty dnodes on a multilist_t, and for spa_sync() to use separate threads to process each of the sublists in the multilist. OpenZFS-issue: https://www.illumos.org/issues/7968 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/4a2a54c Closes #5752
* OpenZFS 7793 - ztest fails assertion in dmu_tx_willuse_spaceBrian Behlendorf2017-03-071-75/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reviewed by: Steve Gonczi <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Ported-by: Brian Behlendorf <[email protected]> Background information: This assertion about tx_space_* verifies that we are not dirtying more stuff than we thought we would. We “need” to know how much we will dirty so that we can check if we should fail this transaction with ENOSPC/EDQUOT, in dmu_tx_assign(). While the transaction is open (i.e. between dmu_tx_assign() and dmu_tx_commit() — typically less than a millisecond), we call dbuf_dirty() on the exact blocks that will be modified. Once this happens, the temporary accounting in tx_space_* is unnecessary, because we know exactly what blocks are newly dirtied; we call dnode_willuse_space() to track this more exact accounting. The fundamental problem causing this bug is that dmu_tx_hold_*() relies on the current state in the DMU (e.g. dn_nlevels) to predict how much will be dirtied by this transaction, but this state can change before we actually perform the transaction (i.e. call dbuf_dirty()). This bug will be fixed by removing the assertion that the tx_space_* accounting is perfectly accurate (i.e. we never dirty more than was predicted by dmu_tx_hold_*()). By removing the requirement that this accounting be perfectly accurate, we can also vastly simplify it, e.g. removing most of the logic in dmu_tx_count_*(). The new tx space accounting will be very approximate, and may be more or less than what is actually dirtied. It will still be used to determine if this transaction will put us over quota. Transactions that are marked by dmu_tx_mark_netfree() will be excepted from this check. We won’t make an attempt to determine how much space will be freed by the transaction — this was rarely accurate enough to determine if a transaction should be permitted when we are over quota, which is why dmu_tx_mark_netfree() was introduced in 2014. We also won’t attempt to give “credit” when overwriting existing blocks, if those blocks may be freed. This allows us to remove the do_free_accounting logic in dbuf_dirty(), and associated routines. This logic attempted to predict what will be on disk when this txg syncs, to know if the overwritten block will be freed (i.e. exists, and has no snapshots). OpenZFS-issue: https://www.illumos.org/issues/7793 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3704e0a Upstream bugs: DLPX-32883a Closes #5804 Porting notes: - DNODE_SIZE replaced with DNODE_MIN_SIZE in dmu_tx_count_dnode(), Using the default dnode size would be slightly better. - DEBUG_DMU_TX wrappers and configure option removed. - Resolved _by_dnode() conflicts these changes have not yet been applied to OpenZFS.
* zfs_arc_num_sublists_per_state should be common to all multilistsMatthew Ahrens2017-02-151-1/+0
| | | | | | | | | | | | | The global tunable zfs_arc_num_sublists_per_state is used by the ARC and the dbuf cache, and other users are planned. We should change this tunable to be common to all multilists. This tuning may be overridden on a per-multilist basis. Reviewed-by: Pavel Zakharov <[email protected]> Reviewed-by: Dan Kimmel <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Matthew Ahrens <[email protected]> Closes #5764
* Remove lint ifdef checks in zdb and dbufGiuseppe Di Natale2017-02-011-2/+0
| | | | | | | | | | This is effectively dead code for the Linux implementation which can be removed to improve readability. We want to linter to check the real production/debug build as much as possible. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: George Melikov <[email protected]> Signed-off-by: Giuseppe Di Natale <[email protected]> Closes #5722
* OpenZFS 7580 - ztest failure in dbuf_read_implGeorge Melikov2017-01-281-3/+9
| | | | | | | | | | | | Authored by: George Wilson <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Steve Gonczi <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: George Melikov <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7580 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3105d95 Closes #5678
* OpenZFS 7254 - ztest failed assertion in ztest_dataset_dirobj_verify: ↵George Melikov2017-01-271-6/+29
| | | | | | | | | | | | | | | | dirobjs + 1 == usedobjs Authored by: Paul Dagnelie <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Steve Gonczi <[email protected]> Approved by: Robert Mustacchi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: George Melikov <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7254 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/c166b69 Closes #5670
* OpenZFS 7500 - Simplify dbuf_free_range by removing dn_unlisted_l0_blkidGeorge Melikov2017-01-261-35/+4
| | | | | | | | | | | | Authored by: Stephen Blinick <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Approved by: Gordon Ross <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: George Melikov <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7500 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/653af1b Closes #5639
* OpenZFS 6676 - Race between unique_insert() and unique_remove() causes ZFS ↵George Melikov2017-01-261-5/+21
| | | | | | | | | | | | | | | | | | fsid change Authored by: Josef 'Jeff' Sipek <[email protected]> Reviewed by: Saso Kiselkov <[email protected]> Reviewed by: Sanjay Nadkarni <[email protected]> Reviewed by: Dan Vatca <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Sebastien Roy <[email protected]> Approved by: Robert Mustacchi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Ported-by: George Melikov <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/6676 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/40510e8 Closes #5667
* codebase style improvements for OpenZFS 6459 portGeorge Melikov2017-01-221-2/+2
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* Fix spellingka72017-01-031-2/+2
| | | | | | | | | Reviewed-by: Brian Behlendorf <[email protected] Reviewed-by: Giuseppe Di Natale <[email protected]>> Reviewed-by: George Melikov <[email protected]> Reviewed-by: Haakan T Johansson <[email protected]> Closes #5547 Closes #5543
* Fix typos in dbuf.cbunder20152016-12-131-5/+5
| | | | | | | | This removes two large whitespaces in "modinfo zfs" as well as correcting a couple typos. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: bunder2015 <[email protected]> Closes #5475
* Use cstyle -cpP in `make cstyle` checkBrian Behlendorf2016-12-121-13/+12
| | | | | | | | | | | | | | | | | | | | | | | 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
* OpenZFS 7143 - dbuf_read() creates unnecessary zio_root() for bonus bufBrian Behlendorf2016-12-011-3/+4
| | | | | | | | | | | | | | | | | | | | | | dbuf_read() creates a zio_root() to track and wait for all the zio's that may happen as part of this call. However, if the blkptr_t for this buffer is NULL or a hole, we will not create any more zio's, so this zio_root() is unnecessary. This is always the case when calling dbuf_read() on a bonus buffer, because it has no blkptr (it's part of the containing dnode). For workloads that read a lot of bonus buffers (e.g. file creation and removal), creating and destroying these unnecessary zio's can decrease performance by around 3%. The fix is to only create/destroy the zio_root() in dbuf_read() if the blkptr is not NULL and not a hole. Changes sponsored by Intel Corp. Authored by: Matthew Ahrens <[email protected]> Reviewed-by: Alex Zhuravlev <[email protected]> Ported-by: Brian Behlendorf <[email protected]> Issue openzfs/openzfs#137 Closes #4803 Closes #5382
* Convert zio_buf_alloc() consumersBrian Behlendorf2016-11-301-5/+4
| | | | | | | | | | | | | | | | | | | In multiple cases zio_buf_alloc() was used instead of kmem_alloc() or vmem_alloc(). This was often done because the allocations could be large and it was easy to use zfs_buf_alloc() for them. But this isn't ideal for allocations which are small or short lived. In these cases it is better to use kmem_alloc() or vmem_alloc(). If possible we want to avoid the case where we have slabs allocated for kmem caches which are rarely used. Note for small allocations vmem_alloc() will be internally converted to kmem_alloc(). Therefore as long as large allocations are infrequent and short lived the penalty for using vmem_alloc() is small. Reviewed-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #5409
* DLPX-44812 integrate EP-220 large memory scalabilityDavid Quigley2016-11-291-1/+6
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* Fix coverity defects: CID 150943, 150938cao2016-10-131-2/+2
| | | | | | | | | CID:150943, Type:Unintentional integer overflow CID:150938, Type:Explicit null dereferenced Reviewed-by: Tom Caputi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: cao.xuewen <[email protected]> Closes #5255
* OpenZFS 4185 - add new cryptographic checksums to ZFS: SHA-512, Skein, Edon-RTony Hutter2016-10-031-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reviewed by: George Wilson <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: Saso Kiselkov <[email protected]> Reviewed by: Richard Lowe <[email protected]> Approved by: Garrett D'Amore <[email protected]> Ported by: Tony Hutter <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/4185 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/45818ee Porting Notes: This code is ported on top of the Illumos Crypto Framework code: https://github.com/zfsonlinux/zfs/pull/4329/commits/b5e030c8dbb9cd393d313571dee4756fbba8c22d The list of porting changes includes: - Copied module/icp/include/sha2/sha2.h directly from illumos - Removed from module/icp/algs/sha2/sha2.c: #pragma inline(SHA256Init, SHA384Init, SHA512Init) - Added 'ctx' to lib/libzfs/libzfs_sendrecv.c:zio_checksum_SHA256() since it now takes in an extra parameter. - Added CTASSERT() to assert.h from for module/zfs/edonr_zfs.c - Added skein & edonr to libicp/Makefile.am - Added sha512.S. It was generated from sha512-x86_64.pl in Illumos. - Updated ztest.c with new fletcher_4_*() args; used NULL for new CTX argument. - In icp/algs/edonr/edonr_byteorder.h, Removed the #if defined(__linux) section to not #include the non-existant endian.h. - In skein_test.c, renane NULL to 0 in "no test vector" array entries to get around a compiler warning. - Fixup test files: - Rename <sys/varargs.h> -> <varargs.h>, <strings.h> -> <string.h>, - Remove <note.h> and define NOTE() as NOP. - Define u_longlong_t - Rename "#!/usr/bin/ksh" -> "#!/bin/ksh -p" - Rename NULL to 0 in "no test vector" array entries to get around a compiler warning. - Remove "for isa in $($ISAINFO); do" stuff - Add/update Makefiles - Add some userspace headers like stdio.h/stdlib.h in places of sys/types.h. - EXPORT_SYMBOL *_Init/*_Update/*_Final... routines in ICP modules. - Update scripts/zfs2zol-patch.sed - include <sys/sha2.h> in sha2_impl.h - Add sha2.h to include/sys/Makefile.am - Add skein and edonr dirs to icp Makefile - Add new checksums to zpool_get.cfg - Move checksum switch block from zfs_secpolicy_setprop() to zfs_check_settable() - Fix -Wuninitialized error in edonr_byteorder.h on PPC - Fix stack frame size errors on ARM32 - Don't unroll loops in Skein on 32-bit to save stack space - Add memory barriers in sha2.c on 32-bit to save stack space - Add filetest_001_pos.ksh checksum sanity test - Add option to write psudorandom data in file_write utility
* fix: Shift exponent too largeGvozden Neskovic2016-09-291-3/+14
| | | | | | | | | | | | Undefined operation is reported by running ztest (or zloop) compiled with GCC UndefinedBehaviorSanitizer. Error only happens on top level of dnode indirection with large enough offset values. Logically, left shift operation would work, but bit shift semantics in C, and limitation of uint64_t, do not produce desired result. Issue #5059, #4883 Signed-off-by: Gvozden Neskovic <[email protected]>
* Reduce noise in tracing logsIsaac Huang2016-09-211-1/+1
| | | | | | | | | dbuf_read_impl() returns (SET_ERROR(err)) when err can be 0, which adds lots of noise in tracing logs. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Isaac Huang <[email protected]> Closes #4430 Closes #5146
* DLPX-40252 integrate EP-476 compressed zfs send/receiveDan Kimmel2016-09-131-71/+102
| | | | | | | | Authored by: Dan Kimmel <[email protected]> Reviewed by: Tom Caputi <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Ported by: David Quigley <[email protected]> Issue #5078
* OpenZFS 6950 - ARC should cache compressed dataGeorge Wilson2016-09-131-206/+452
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Authored by: George Wilson <[email protected]> Reviewed by: Prakash Surya <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Tom Caputi <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Ported by: David Quigley <[email protected]> This review covers the reading and writing of compressed arc headers, sharing data between the arc_hdr_t and the arc_buf_t, and the implementation of a new dbuf cache to keep frequently access data uncompressed. I've added a new member to l1 arc hdr called b_pdata. The b_pdata always hangs off the arc_buf_hdr_t (if an L1 hdr is in use) and points to the physical block for that DVA. The physical block may or may not be compressed. If compressed arc is enabled and the block on-disk is compressed, then the b_pdata will match the block on-disk and remain compressed in memory. If the block on disk is not compressed, then neither will the b_pdata. Lastly, if compressed arc is disabled, then b_pdata will always be an uncompressed version of the on-disk block. Typically the arc will cache only the arc_buf_hdr_t and will aggressively evict any arc_buf_t's that are no longer referenced. This means that the arc will primarily have compressed blocks as the arc_buf_t's are considered overhead and are always uncompressed. When a consumer reads a block we first look to see if the arc_buf_hdr_t is cached. If the hdr is cached then we allocate a new arc_buf_t and decompress the b_pdata contents into the arc_buf_t's b_data. If the hdr already has a arc_buf_t, then we will allocate an additional arc_buf_t and bcopy the uncompressed contents from the first arc_buf_t to the new one. Writing to the compressed arc requires that we first discard the b_pdata since the physical block is about to be rewritten. The new data contents will be passed in via an arc_buf_t (uncompressed) and during the I/O pipeline stages we will copy the physical block contents to a newly allocated b_pdata. When an l2arc is inuse it will also take advantage of the b_pdata. Now the l2arc will always write the contents of b_pdata to the l2arc. This means that when compressed arc is enabled that the l2arc blocks are identical to those stored in the main data pool. This provides a significant advantage since we can leverage the bp's checksum when reading from the l2arc to determine if the contents are valid. If the compressed arc is disabled, then we must first transform the read block to look like the physical block in the main data pool before comparing the checksum and determining it's valid. OpenZFS-issue: https://www.illumos.org/issues/6950 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7fc10f0 Issue #5078
* OpenZFS 6322 - ZFS indirect block predictive prefetchAlexander Motin2016-08-301-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For quite some time I was thinking about possibility to prefetch ZFS indirection tables while doing sequential reads or writes. Recent changes in predictive prefetcher made that much easier to do. My tests on zvol with 16KB block size on 5x striped and 2x mirrored pool of 10 disks show almost double throughput on sequential read, and almost tripple on sequential rewrite. While for read alike effect can be received from increasing maximal prefetch distance (though at higher memory cost), for rewrite there is no other solution so far. Authored by: Alexander Motin <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Approved by: Robert Mustacchi <[email protected]> Ported-by: kernelOfTruth [email protected] Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/6322 OpenZFS-commit: https://github.com/illumos/illumos-gate/commit/cb92f413 Closes #5040 Porting notes: - Change from upstream in module/zfs/dbuf.c in 'int dbuf_read' due to commit 5f6d0b6 'Handle block pointers with a corrupt logical size' - Difference from upstream in module/zfs/dmu_zfetch.c, uint32_t zfetch_max_idistance -> unsigned int zfetch_max_idistance - Variables have been initialized at the beginning of the function (void dmu_zfetch) to resemble the order of occurrence and account for C99, C11 mode errors.
* OpenZFS 7086 - ztest attempts dva_get_dsize_sync on an embedded blockpointerMatthew Ahrens2016-08-301-6/+14
| | | | | | | | | | | | | In dbuf_dirty(), we need to grab the dn_struct_rwlock before looking at the db_blkptr, to prevent it from being changed by syncing context. Reviewed by: Prakash Surya <[email protected]> Reviewed by: George Wilson <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7086 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/98fa317 Closes #5039
* OpenZFS 7004 - dmu_tx_hold_zap() does dnode_hold() 7x on same objectMatthew Ahrens2016-08-191-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using a benchmark which has 32 threads creating 2 million files in the same directory, on a machine with 16 CPU cores, I observed poor performance. I noticed that dmu_tx_hold_zap() was using about 30% of all CPU, and doing dnode_hold() 7 times on the same object (the ZAP object that is being held). dmu_tx_hold_zap() keeps a hold on the dnode_t the entire time it is running, in dmu_tx_hold_t:txh_dnode, so it would be nice to use the dnode_t that we already have in hand, rather than repeatedly calling dnode_hold(). To do this, we need to pass the dnode_t down through all the intermediate calls that dmu_tx_hold_zap() makes, making these routines take the dnode_t* rather than an objset_t* and a uint64_t object number. In particular, the following routines will need to have analogous *_by_dnode() variants created: dmu_buf_hold_noread() dmu_buf_hold() zap_lookup() zap_lookup_norm() zap_count_write() zap_lockdir() zap_count_write() This can improve performance on the benchmark described above by 100%, from 30,000 file creations per second to 60,000. (This improvement is on top of that provided by working around the object allocation issue. Peak performance of ~90,000 creations per second was observed with 8 CPUs; adding CPUs past that decreased performance due to lock contention.) The CPU used by dmu_tx_hold_zap() was reduced by 88%, from 340 CPU-seconds to 40 CPU-seconds. Sponsored by: Intel Corp. Signed-off-by: Matthew Ahrens <[email protected]> Signed-off-by: Ned Bass <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7004 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/109 Closes #4641 Closes #4972
* OpenZFS 7003 - zap_lockdir() should tag holdMatthew Ahrens2016-08-191-0/+7
| | | | | | | | | | | | | | | | zap_lockdir() / zap_unlockdir() should take a "void *tag" argument which tags the hold on the zap. This will help diagnose programming errors which misuse the hold on the ZAP. Sponsored by: Intel Corp. Signed-off-by: Matthew Ahrens <[email protected]> Signed-off-by: Pavel Zakharov <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7003 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/108 Closes #4972
* OpenZFS 7176 - Yet another hole birth issuePaul Dagnelie2016-08-181-6/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is another bug in the long line of hole-birth related issues. In this particular case, it was discovered that a previous hole-birth fix (illumos bug 6513, commit bc77ba73) did not cover as many cases as we thought it did. While the issue worked in the case of hole-punching (writing zeroes to a large part of a file), it did not deal with truncation, and then writing beyond the new end of the file. The problem is that dbuf_findbp will return ENOENT if the block it's trying to find is beyond the end of the file. If that happens, we assume there is no birth time, and so we lose that information when we write out new blkptrs. We should teach dbuf_findbp to look for things that are beyond the current end, but not beyond the absolute end of the file. Authored by: Paul Dagnelie <[email protected]> Reviewed by: Matthew Ahrens [email protected] Reviewed by: George Wilson [email protected] Ported-by: kernelOfTruth <[email protected]> Signed-off-by: Boris Protopopov <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/7176 OpenZFS-commit: https://github.com/openzfs/openzfs/pull/173/commits/8b9f3ad Upstream-bugs: DLPX-46009 Porting notes: - Fix ISO C90 mixed declaration error in dbuf.c ( int nlevels, epbs; ) ; keep previous position of the initialization
* It is not necessary to zero struct dbuf_hold_impl_dataMatthew Ahrens2016-08-161-1/+9
| | | | | | | | | | | | | | | | | | | | | Under a workload which makes heavy use of `dbuf_hold()`, I noticed that a considerable amount of time was spent in `dbuf_hold_impl()`, due to its call to `kmem_zalloc(sizeof (struct dbuf_hold_impl_data) * DBUF_HOLD_IMPL_MAX_DEPTH)`, which is around 2KiB. This structure is used as a stack, to limit the size of the C stack as dbuf_hold() calls itself recursively. We make a recursive call to hold the parent's dbuf when the requested dbuf is not found. The vast majority of the time, the parent or grandparent indirect dbuf is cached, so the number of recursive calls is very low. However, we initialize this entire array for every call to dbuf_hold(). To improve performance, this commit changes `dbuf_hold()` to use `kmem_alloc()` instead of `kmem_zalloc()`. __dbuf_hold_impl_init is changed to initialize all members of the struct before they are used. I observed ~5% performance improvement on a workload which creates many files. Signed-off-by: Matthew Ahrens <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #4974
* Limit the amount of dnode metadata in the ARCTim Chase2016-07-251-7/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Metadata-intensive workloads can cause the ARC to become permanently filled with dnode_t objects as they're pinned by the VFS layer. Subsequent data-intensive workloads may only benefit from about 25% of the potential ARC (arc_c_max - arc_meta_limit). In order to help track metadata usage more precisely, the other_size metadata arcstat has replaced with dbuf_size, dnode_size and bonus_size. The new zfs_arc_dnode_limit tunable, which defaults to 10% of zfs_arc_meta_limit, defines the minimum number of bytes which is desirable to be consumed by dnodes. Attempts to evict non-metadata will trigger async prune tasks if the space used by dnodes exceeds this limit. The new zfs_arc_dnode_reduce_percent tunable specifies the amount by which the excess dnode space is attempted to be pruned as a percentage of the amount by which zfs_arc_dnode_limit is being exceeded. By default, it tries to unpin 10% of the dnodes. The problem of dnode metadata pinning was observed with the following testing procedure (in this example, zfs_arc_max is set to 4GiB): - Create a large number of small files until arc_meta_used exceeds arc_meta_limit (3GiB with default tuning) and arc_prune starts increasing. - Create a 3GiB file with dd. Observe arc_mata_used. It will still be around 3GiB. - Repeatedly read the 3GiB file and observe arc_meta_limit as before. It will continue to stay around 3GiB. With this modification, space for the 3GiB file is gradually made available as subsequent demands on the ARC are made. The previous behavior can be restored by setting zfs_arc_dnode_limit to the same value as the zfs_arc_meta_limit. Signed-off-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #4345 Issue #4512 Issue #4773 Closes #4858
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