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* txg visibility code should not execute under tc_open_lockRichard Yao2016-07-271-4/+5
| | | | | | | | | The memory allocation and locking in `spa_txg_history_*()` can potentially block txg_hold_open for arbitrarily long periods of time. Signed-off-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #4333
* Increase default user space stack sizeBrian Behlendorf2016-01-131-1/+1
| | | | | | | | | | | | | | | | | | | | Under RHEL6/CentOS6 the default stack size must be increased to 32K to prevent overflowing the stack when running ztest. This isn't an issue for other distributions due to either the version of pthreads or perhaps the compiler. Doubling the stack size resolves the issue safely for all distribution and leaves us some headroom. $ sudo -E ztest -V -T 300 -f /var/tmp/ 5 vdevs, 7 datasets, 23 threads, 300 seconds... loading space map for vdev 0 of 1, metaslab 0 of 30 ... ... loading space map for vdev 0 of 1, metaslab 14 of 30 ... child died with signal 11 Exited ztest with error 3 Signed-off-by: Brian Behlendorf <[email protected]> Closes #4215
* Identify locks flagged by lockdepOlaf Faaland2015-12-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running a kernel with CONFIG_LOCKDEP=y, lockdep reports possible recursive locking in some cases and possible circular locking dependency in others, within the SPL and ZFS modules. This patch uses a mutex type defined in SPL, MUTEX_NOLOCKDEP, to mark such mutexes when they are initialized. This mutex type causes attempts to take or release those locks to be wrapped in lockdep_off() and lockdep_on() calls to silence the dependency checker and allow the use of lock_stats to examine contention. For RW locks, it uses an analogous lock type, RW_NOLOCKDEP. The goal is that these locks are ultimately changed back to type MUTEX_DEFAULT or RW_DEFAULT, after the locks are annotated to reflect their relationship (e.g. z_name_lock below) or any real problem with the lock dependencies are fixed. Some of the affected locks are: tc_open_lock: ============= This is an array of locks, all with same name, which txg_quiesce must take all of in order to move txg to next state. All default to the same lockdep class, and so to lockdep appears recursive. zp->z_name_lock: ================ In zfs_rmdir, dzp = znode for the directory (input to zfs_dirent_lock) zp = znode for the entry being removed (output of zfs_dirent_lock) zfs_rmdir()->zfs_dirent_lock() takes z_name_lock in dzp zfs_rmdir() takes z_name_lock in zp Since both dzp and zp are type znode_t, the locks have the same default class, and lockdep considers it a possible recursive lock attempt. l->l_rwlock: ============ zap_expand_leaf() sometimes creates two new zap leaf structures, via these call paths: zap_deref_leaf()->zap_get_leaf_byblk()->zap_leaf_open() zap_expand_leaf()->zap_create_leaf()->zap_expand_leaf()->zap_create_leaf() Because both zap_leaf_open() and zap_create_leaf() initialize l->l_rwlock in their (separate) leaf structures, the lockdep class is the same, and the linux kernel believes these might both be the same lock, and emits a possible recursive lock warning. Signed-off-by: Olaf Faaland <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #3895
* Align thread priority with Linux defaultsBrian Behlendorf2015-07-281-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Under Linux filesystem threads responsible for handling I/O are normally created with the maximum priority. Non-I/O filesystem processes run with the default priority. ZFS should adopt the same priority scheme under Linux to maintain good performance and so that it will complete fairly when other Linux filesystems are active. The priorities have been updated to the following: $ ps -eLo rtprio,cls,pid,pri,nice,cmd | egrep 'z_|spl_|zvol|arc|dbu|meta' - TS 10743 19 -20 [spl_kmem_cache] - TS 10744 19 -20 [spl_system_task] - TS 10745 19 -20 [spl_dynamic_tas] - TS 10764 19 0 [dbu_evict] - TS 10765 19 0 [arc_prune] - TS 10766 19 0 [arc_reclaim] - TS 10767 19 0 [arc_user_evicts] - TS 10768 19 0 [l2arc_feed] - TS 10769 39 0 [z_unmount] - TS 10770 39 -20 [zvol] - TS 11011 39 -20 [z_null_iss] - TS 11012 39 -20 [z_null_int] - TS 11013 39 -20 [z_rd_iss] - TS 11014 39 -20 [z_rd_int_0] - TS 11022 38 -19 [z_wr_iss] - TS 11023 39 -20 [z_wr_iss_h] - TS 11024 39 -20 [z_wr_int_0] - TS 11032 39 -20 [z_wr_int_h] - TS 11033 39 -20 [z_fr_iss_0] - TS 11041 39 -20 [z_fr_int] - TS 11042 39 -20 [z_cl_iss] - TS 11043 39 -20 [z_cl_int] - TS 11044 39 -20 [z_ioctl_iss] - TS 11045 39 -20 [z_ioctl_int] - TS 11046 39 -20 [metaslab_group_] - TS 11050 19 0 [z_iput] - TS 11121 38 -19 [z_wr_iss] Note that under Linux the meaning of a processes priority is inverted with respect to illumos. High values on Linux indicate a _low_ priority while high value on illumos indicate a _high_ priority. In order to preserve the logical meaning of the minclsyspri and maxclsyspri macros when they are used by the illumos wrapper functions their values have been inverted. This way when changes are merged from upstream illumos we won't need to remember to invert the macro. It could also lead to confusion. This patch depends on https://github.com/zfsonlinux/spl/pull/466. Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Ned Bass <[email protected]> Closes #3607
* Update all default taskq settingsBrian Behlendorf2015-06-251-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Over the years the default values for the taskqs used on Linux have differed slightly from illumos. In the vast majority of cases this was done to avoid creating an obnoxious number of idle threads which would pollute the process listing. With the addition of support for dynamic taskqs all multi-threaded queues should be created as dynamic taskqs. This allows us to get the best of both worlds. * The illumos default values for the I/O pipeline can be restored. These values are known to work well for most workloads. The only exception is the zio write interrupt taskq which is changed to ZTI_P(12, 8). At least under Linux more threads has been shown to improve performance, see commit 7e55f4e. * Reduces the number of idle threads on the system when it's not under heavy load. The maximum number of threads will only be created when they are required. * Remove the vdev_file_taskq and rely on the system_taskq instead which is now dynamic and may have up to 64-threads. Again this brings us back inline with upstream. * Tasks dispatched with taskq_dispatch_ent() are allowed to use dynamic taskqs. The Linux taskq implementation supports this. Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Tim Chase <[email protected]> Closes #3507
* Rename cv_wait_interruptible() to cv_wait_sig()Brian Behlendorf2015-06-111-2/+2
| | | | | | | | | | | This is the counterpart to zfsonlinux/spl@2345368 which replaces the cv_wait_interruptible() function with cv_wait_sig(). There is no functional change to patch merely brings the function names in to sync to maximize portability. Signed-off-by: Brian Behlendorf <[email protected]> Issue #3450 Issue #3402
* Use taskq_wait_outstanding() functionBrian Behlendorf2015-06-111-1/+1
| | | | | | | | | | | Replace taskq_wait() with taskq_wait_oustanding(). This way callers will only block until previously submitted tasks have been completed. This was the previous behavior of task_wait() prior to the introduction of taskq_wait_outstanding() so this isn't really a functionalty change for these callers. Signed-off-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]>
* Change KM_PUSHPAGE -> KM_SLEEPBrian Behlendorf2015-01-161-3/+3
| | | | | | | | | | | | | | | By marking DMU transaction processing contexts with PF_FSTRANS we can revert the KM_PUSHPAGE -> KM_SLEEP changes. This brings us back in line with upstream. In some cases this means simply swapping the flags back. For others fnvlist_alloc() was replaced by nvlist_alloc(..., KM_PUSHPAGE) and must be reverted back to fnvlist_alloc() which assumes KM_SLEEP. The one place KM_PUSHPAGE is kept is when allocating ARC buffers which allows us to dip in to reserved memory. This is again the same as upstream. Signed-off-by: Brian Behlendorf <[email protected]>
* Mark IO pipeline with PF_FSTRANSBrian Behlendorf2015-01-161-9/+1
| | | | | | | | | | In order to avoid deadlocking in the IO pipeline it is critical that pageout be avoided during direct memory reclaim. This ensures that the pipeline threads can always make forward progress and never end up blocking on a DMU transaction. For this very reason Linux now provides the PF_FSTRANS flag which may be set in the process context. Signed-off-by: Brian Behlendorf <[email protected]>
* Remove duplicate typedefs from trace.hNed Bass2015-01-061-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Older versions of GCC (e.g. GCC 4.4.7 on RHEL6) do not allow duplicate typedef declarations with the same type. The trace.h header contains some typedefs to avoid 'unknown type' errors for C files that haven't declared the type in question. But this causes build failures for C files that have already declared the type. Newer versions of GCC (e.g. v4.6) allow duplicate typedefs with the same type unless pedantic error checking is in force. To support the older versions we need to remove the duplicate typedefs. Removal of the typedefs means we can't built tracepoints code using those types unless the required headers have been included. To facilitate this, all tracepoint event declarations have been moved out of trace.h into separate headers. Each new header is explicitly included from the C file that uses the events defined therein. The trace.h header is still indirectly included form zfs_context.h and provides the implementation of the dprintf(), dbgmsg(), and SET_ERROR() interfaces. This makes those interfaces readily available throughout the code base. The macros that redefine DTRACE_PROBE* to use Linux tracepoints are also still provided by trace.h, so it is a prerequisite for the other trace_*.h headers. These new Linux implementation-specific headers do introduce a small divergence from upstream ZFS in several core C files, but this should not present a significant maintenance burden. Signed-off-by: Ned Bass <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #2953
* Illumos 4753 - increase number of outstanding async writes when sync task is ↵Alex Reece2014-09-231-1/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Illumos 4976-4984 - metaslab improvementsGeorge Wilson2014-08-181-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 4976 zfs should only avoid writing to a failing non-redundant top-level vdev 4978 ztest fails in get_metaslab_refcount() 4979 extend free space histogram to device and pool 4980 metaslabs should have a fragmentation metric 4981 remove fragmented ops vector from block allocator 4982 space_map object should proactively upgrade when feature is enabled 4983 need to collect metaslab information via mdb 4984 device selection should use fragmentation metric Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Adam Leventhal <[email protected]> Reviewed by: Christopher Siden <[email protected]> Approved by: Garrett D'Amore <[email protected]> References: https://www.illumos.org/issues/4976 https://www.illumos.org/issues/4978 https://www.illumos.org/issues/4979 https://www.illumos.org/issues/4980 https://www.illumos.org/issues/4981 https://www.illumos.org/issues/4982 https://www.illumos.org/issues/4983 https://www.illumos.org/issues/4984 https://github.com/illumos/illumos-gate/commit/2e4c998 Notes: The "zdb -M" option has been re-tasked to display the new metaslab fragmentation metric and the new "zdb -I" option is used to control the maximum number of in-flight I/Os. The new fragmentation metric is derived from the space map histogram which has been rolled up to the vdev and pool level and is presented to the user via "zpool list". Add a number of module parameters related to the new metaslab weighting logic. Ported by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #2595
* Use ddi_time_after and friends to compare timeChunwei Chen2014-04-141-2/+2
| | | | | | | | | Also, make sure we use clock_t for ddi_get_lbolt to prevent type conversion from screwing things. Signed-off-by: Chunwei Chen <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #2142
* replace nreserved with ndirty in txgs kstatNed Bass2014-03-041-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | The nreserved column in the txgs kstat file always contains 0 following the write throttle restructuring of commit e8b96c6007bf97cdf34869c1ffbd0ce753873a3d. Prior to that commit, the nreserved column showed the number of bytes temporarily reserved in the pool by a transaction group at sync time. The new write throttle did away with temporary reservations and uses the amount of dirty data instead. To approximate the old output of the txgs kstat, the number of dirty bytes per-txg was passed in as the nreserved value to spa_txg_history_set_io(). This approach did not work as intended, because the per-txg dirty value is decremented as data is written out to disk, so it is zero by the time we call spa_txg_history_set_io(). To fix this, save the number of dirty bytes before calling spa_sync(), and pass this value in to spa_txg_history_set_io(). Also, since the name "nreserved" is now a misnomer, the column heading is now labeled "ndirty". Signed-off-by: Ned Bass <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #1696
* Call gethrtime() only once per new txg creationCyril Plisko2014-01-231-2/+2
| | | | | | | | | | | | | | | | | | | | | | | When transitioning current open TXG into QUIESCE state and opening a new one txg_quiesce() calls gethrtime(): - to mark the birth time of the new TXG - to record the SPA txg history kstat - implicitely inside spa_txg_history_add() These timestamps are practically the same, so that the first one can be used instead of the other two. The only visible difference is that inside spa_txg_history_add() the time spent in kmem_zalloc() will be counted towards the opened TXG. Since at this point the new TXG already exists (tx->tx_open_txg has been already incremented) it is actually a correct accounting. In any case this extra work is only happening when spa_txg_history kstat is activated (i.e. zfs_txg_history > 0) and doesn't affect the normal processing in any way. Signed-off-by: Cyril Plisko <[email protected]> Issue #2075
* Add additional state TXG_STATE_WAIT_FOR_SYNC for txg.Igor Lvovsky2014-01-231-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | In several cases when digging into kstats we can found two txgs in SYNC state, e.g. txg birth state nreserved nread nwritten ... 985452 258127184872561 C 0 373948416 2376272384 ... 985453 258129016180616 C 0 378173440 28793344 ... 985454 258129016271523 S 0 0 0 ... 985455 258130864245986 S 0 0 0 ... 985456 258130867458851 O 0 0 0 ... However only first txg (985454) is really syncing at this moment. The other one (985455) marked as SYNCED is actually in a post-QUIESCED state and waiting to start sync. So, the new TXG_STATE_WAIT_FOR_SYNC state between TXG_STATE_QUIESCED and TXG_STATE_SYNCED was added to reveal this situation. txg birth state nreserved nread nwritten ... 1086896 235261068743969 C 0 163577856 8437248 ... 1086897 235262870830801 C 0 280625152 822594048 ... 1086898 235264172219064 S 0 0 0 ... 1086899 235264936134407 W 0 0 0 ... 1086900 235264936296156 O 0 0 0 ... Signed-off-by: Igor Lvovsky <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #2075
* cstyle: Resolve C style issuesMichael Kjorling2013-12-181-4/+4
| | | | | | | | | | | | | | | | | | 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 Ahrens2013-12-061-5/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Andrews2013-11-041-1/+1
| | | | | | | | | | | | | | | | | | | | | 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 #3741Will Andrews2013-11-041-1/+13
| | | | | | | | | | | | | | | 3741 zfs needs better comments Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Eric Schrock <[email protected]> Approved by: Christopher Siden <[email protected]> References: https://www.illumos.org/issues/3741 illumos/illumos-gate@3e30c24aeefdee1631958ecf17f18da671781956 Ported-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #1775
* Illumos #3582, #3584Adam Leventhal2013-11-041-10/+17
| | | | | | | | | | | | | | | | | | | | 3582 zfs_delay() should support a variable resolution 3584 DTrace sdt probes for ZFS txg states Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Christopher Siden <[email protected]> Reviewed by: Dan McDonald <[email protected]> Reviewed by: Richard Elling <[email protected]> Approved by: Garrett D'Amore <[email protected]> References: https://www.illumos.org/issues/3582 illumos/illumos-gate@0689f76 Ported by: Ned Bass <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #1775
* Illumos #3642, #3643George Wilson2013-11-011-6/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | 3642 dsl_scan_active() should not issue I/O to determine if async destroying is active 3643 txg_delay should not hold the tc_lock Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Adam Leventhal <[email protected]> Approved by: Gordon Ross <[email protected]> References: https://www.illumos.org/issues/3642 https://www.illumos.org/issues/3643 illumos/illumos-gate@4a92375985c37d61406d66cd2b10ee642eb1f5e7 Ported-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #1775 Porting Notes: 1. The alignment assumptions for the tx_cpu structure assume that a kmutex_t is 8 bytes. This isn't true under Linux but tc_pad[] was adjusted anyway for consistency since this structure was never carefully aligned in ZoL. If careful alignment does impact performance significantly this should be reworked to be portable.
* Add visibility in to txg sync behaviorBrian Behlendorf2013-10-251-1/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change is an attempt to add visibility in to how txgs are being formed on a system, in real time. To do this, a list was added to the in memory SPA data structure for a pool, with each element on the list corresponding to txg. These entries are then exported through the kstat interface, which can then be interpreted in userspace. For each txg, the following information is exported: * Unique txg number (uint64_t) * The time the txd was born (hrtime_t) (*not* wall clock time; relative to the other entries on the list) * The current txg state ((O)pen/(Q)uiescing/(S)yncing/(C)ommitted) * The number of reserved bytes for the txg (uint64_t) * The number of bytes read during the txg (uint64_t) * The number of bytes written during the txg (uint64_t) * The number of read operations during the txg (uint64_t) * The number of write operations during the txg (uint64_t) * The time the txg was closed (hrtime_t) * The time the txg was quiesced (hrtime_t) * The time the txg was synced (hrtime_t) Note that while the raw kstat now stores relative hrtimes for the open, quiesce, and sync times. Those relative times are used to calculate how long each state took and these deltas and printed by output handlers. Signed-off-by: Brian Behlendorf <[email protected]>
* Revert "Add txgs-<pool> kstat file"Brian Behlendorf2013-10-251-46/+0
| | | | This reverts commit e95853a331529a6cb96fdf10476c53441e59f4e1.
* Illumos #3464Matthew Ahrens2013-09-041-16/+21
| | | | | | | | | | | | | | | | | 3464 zfs synctask code needs restructuring Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Adam Leventhal <[email protected]> Reviewed by: George Wilson <[email protected]> Reviewed by: Christopher Siden <[email protected]> Approved by: Garrett D'Amore <[email protected]> References: https://www.illumos.org/issues/3464 illumos/illumos-gate@3b2aab18808792cbd248a12f1edf139b89833c13 Ported-by: Tim Chase <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #1495
* Fix txg_quiesce thread deadlockBrian Behlendorf2013-04-261-7/+7
| | | | | | | | | | | | | | | | | | A deadlock was accidentally introduced by commit e95853a which can occur when the system is under memory pressure. What happens is that while the txg_quiesce thread is holding the tx->tx_cpu locks it enters memory reclaim. In the context of this memory reclaim it then issues synchronous I/O to a ZVOL swap device. Because the txg_quiesce thread is holding the tx->tx_cpu locks a new txg cannot be opened to handle the I/O. Deadlock. The fix is straight forward. Move the memory allocation outside the critical region where the tx->tx_cpu locks are held. And for good measure change the offending allocation to KM_PUSHPAGE to ensure it never attempts to issue I/O during reclaim. Signed-off-by: Brian Behlendorf <[email protected]> Issue #1274
* Illumos #3447 improve the comment in txg.cAdam H. Leventhal2013-01-301-2/+71
| | | | | | | | | | | | | | | | 3447 improve the comment in txg.c Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: Richard Lowe <[email protected]> Reviewed by: Garrett D'Amore <[email protected]> Reviewed by: Richard Elling <[email protected]> Approved by: Dan McDonald <[email protected]> References: illumos/illumos-gate@adbbcfface63b3a71922d5a25d34a2018c0435de https://www.illumos.org/issues/3447 Ported-by: Brian Behlendorf <[email protected]>
* Illumos #3086: unnecessarily setting DS_FLAG_INCONSISTENT on asyncMatthew Ahrens2013-01-081-1/+3
| | | | | | | | | | | | | | 3086 unnecessarily setting DS_FLAG_INCONSISTENT on async destroyed datasets Reviewed by: Christopher Siden <[email protected]> Approved by: Eric Schrock <[email protected]> References: illumos/illumos-gate@ce636f8b38e8c9ff484e880d9abb27251a882860 illumos changeset: 13776:cd512c80fd75 https://www.illumos.org/issues/3086 Ported-by: Brian Behlendorf <[email protected]>
* Add txgs-<pool> kstat fileBrian Behlendorf2012-11-021-0/+46
| | | | | | | | | | | | | | | | | | | | Create a kstat file which contains useful statistics about the last N txgs processed. This can be helpful when analyzing pool performance. The new KSTAT_TYPE_TXG type was added for this purpose and it tracks the following statistics per-txg. txg - Unique txg number state - State (O)pen/(Q)uiescing/(S)yncing/(C)ommitted birth; - Creation time nread - Bytes read nwritten; - Bytes written reads - IOPs read writes - IOPs write open_time; - Length in nanoseconds the txg was open quiesce_time - Length in nanoseconds the txg was quiescing sync_time; - Length in nanoseconds the txg was syncing Signed-off-by: Brian Behlendorf <[email protected]>
* Fix zfs_txg_timeout module parameterBrian Behlendorf2012-10-111-1/+6
| | | | | | | | | | | | | | | | Allow the zfs_txg_timeout variable to be dynamically tuned at run time. By pulling it down out of the variable declaration it will be evaluted each time through the loop. The zfs_txg_timeout variable is now declared extern in a the common sys/txg.h header rather than locally in dsl_scan.c. This prevents potential type mismatches if the global variable needs to be used elsewhere. Move the module_param() code in to the same source file where zfs_txg_timeout is declared. This is the most logical location. Signed-off-by: Brian Behlendorf <[email protected]>
* Switch KM_SLEEP to KM_PUSHPAGERichard Yao2012-08-271-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Differences between how paging is done on Solaris and Linux can cause deadlocks if KM_SLEEP is used in any the following contexts. * The txg_sync thread * The zvol write/discard threads * The zpl_putpage() VFS callback This is because KM_SLEEP will allow for direct reclaim which may result in the VM calling back in to the filesystem or block layer to write out pages. If a lock is held over this operation the potential exists to deadlock the system. To ensure forward progress all memory allocations in these contexts must us KM_PUSHPAGE which disables performing any I/O to accomplish the memory allocation. Previously, this behavior was acheived by setting PF_MEMALLOC on the thread. However, that resulted in unexpected side effects such as the exhaustion of pages in ZONE_DMA. This approach touchs more of the zfs code, but it is more consistent with the right way to handle these cases under Linux. This is patch lays the ground work for being able to safely revert the following commits which used PF_MEMALLOC: 21ade34 Disable direct reclaim for z_wr_* threads cfc9a5c Fix zpl_writepage() deadlock eec8164 Fix ASSERTION(!dsl_pool_sync_context(tx->tx_pool)) Signed-off-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #726
* Annotate KM_PUSHPAGE call paths with PF_NOFSBrian Behlendorf2012-08-271-0/+9
| | | | | | | | | | | | | | | | | The txg_sync(), zfs_putpage(), zvol_write(), and zvol_discard() call paths must only use KM_PUSHPAGE to avoid potential deadlocks during direct reclaim. This patch annotates these call paths so any accidental use of KM_SLEEP will be quickly detected. In the interest of stability if debugging is disabled the offending allocation will have its GFP flags automatically corrected. When debugging is enabled any misuse will be treated as a fatal error. This patch is entirely for debugging. We should be careful to NOT become dependant on it fixing up the incorrect allocations. Signed-off-by: Brian Behlendorf <[email protected]>
* Revert Fix ASSERTION(!dsl_pool_sync_context(tx->tx_pool))Richard Yao2012-08-271-13/+0
| | | | | | | | | | | Commit eec8164771bee067c3cd55ed0a16dadeeba276de worked around an issue involving direct reclaim through the use of PF_MEMALLOC. Since we are reworking thing to use KM_PUSHPAGE so that swap works, we revert this patch in favor of the use of KM_PUSHPAGE in the affected areas. Signed-off-by: Richard Yao <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Issue #726
* Wrap smp_processor_id in kpreempt_[dis|en]ablePrakash Surya2012-08-241-1/+11
| | | | | | | | | | | | | After surveying the code, the few places where smp_processor_id is used were deemed to be safe to use with a preempt enabled kernel. As such, no core logic had to be changed. These smp_processor_id call sites are simply are wrapped in kpreempt_disable and kpreempt_enabled to prevent the Linux kernel from emitting scary warnings. Signed-off-by: Prakash Surya <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Signed-off-by: Richard Yao <[email protected]> Issue #83
* Add 'dmu_tx' kstats entryBrian Behlendorf2012-02-271-0/+2
| | | | | | | | | Keep counters for the various reasons that a thread may end up in txg_wait_open() waiting on a new txg. This can be useful when attempting to determine why a particular workload is under performing. Signed-off-by: Brian Behlendorf <[email protected]>
* Illumos #1313: Integer overflow in txg_delay()Martin Matuska2011-08-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function txg_delay() is used to delay txg (transaction group) threads in ZFS. The timeout value for this function is calculated using: int timeout = ddi_get_lbolt() + ticks; Later, the actual wait is performed: while (ddi_get_lbolt() < timeout && tx->tx_syncing_txg < txg-1 && !txg_stalled(dp)) (void) cv_timedwait(&tx->tx_quiesce_more_cv, &tx->tx_sync_lock, timeout - ddi_get_lbolt()); The ddi_get_lbolt() function returns current uptime in clock ticks and is typed as clock_t. The clock_t type on 64-bit architectures is int64_t. The "timeout" variable will overflow depending on the tick frequency (e.g. for 1000 it will overflow in 28.855 days). This will make the expression "ddi_get_lbolt() < timeout" always false - txg threads will not be delayed anymore at all. This leads to a slowdown in ZFS writes. The attached patch initializes timeout as clock_t to match the return value of ddi_get_lbolt(). Signed-off-by: Brian Behlendorf <[email protected]> Issue #352
* Fix ASSERTION(!dsl_pool_sync_context(tx->tx_pool))Brian Behlendorf2011-04-071-0/+13
| | | | | | | | | | Disable the normal reclaim path for the txg_sync thread. This ensures the thread will never enter dmu_tx_assign() which can otherwise occur due to direct reclaim. If this is allowed to happen the system can deadlock. Direct reclaim call path: ->shrink_icache_memory->prune_icache->dispose_list-> clear_inode->zpl_clear_inode->zfs_inactive->dmu_tx_assign
* Fix inflated load averageBrian Behlendorf2011-03-311-2/+2
| | | | | | | | | | | | | | | Kernel threads which sleep uninterruptibly on Linux are marked in the (D) state. These threads are usually in the process of performing IO and are thus counted against the load average. The txg_quiesce and txg_sync threads were always sleeping uninterruptibly and thus inflating the load average. This change makes them sleep interruptibly. Some care is required however because these threads may now be woken early by signals. In this case the callers are all careful to check that the required conditions are met after waking up. If we're woken early due to a signal they will simply go back to sleep. In this case these changes are safe. Closes #175
* Add API to wait for pending commit callbacksRicardo M. Correia2011-02-161-0/+15
| | | | | | | | This adds an API to wait for pending commit callbacks of already-synced transactions to finish processing. This is needed by the DMU-OSD in Lustre during device finalization when some callbacks may still not be called, this leads to non-zero reference count errors. See lustre.org bug 23931.
* Add linux kernel module supportBrian Behlendorf2010-08-311-0/+16
| | | | | | | | | | | 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]>
* Add linux kernel memory supportBrian Behlendorf2010-08-311-2/+2
| | | | | | Required kmem/vmem changes Signed-off-by: Brian Behlendorf <[email protected]>
* Fix commit callbacksRicardo M. Correia2010-08-311-3/+3
| | | | | | | | | | | | | | | | | | | | | | The upstream commit cb code had a few bugs: 1) The arguments of the list_move_tail() call in txg_dispatch_callbacks() were reversed by mistake. This caused the commit callbacks to not be called at all. 2) ztest had a bug in ztest_dmu_commit_callbacks() where "error" was not initialized correctly. This seems to have caused the test to always take the simulated error code path, which made ztest unable to detect whether commit cbs were being called for transactions that successfuly complete. 3) ztest had another bug in ztest_dmu_commit_callbacks() where the commit cb threshold was not being compared correctly. 4) The commit cb taskq was using 'max_ncpus * 2' as the maxalloc argument of taskq_create(), which could have caused unnecessary delays in the txg sync thread. Signed-off-by: Brian Behlendorf <[email protected]>
* Update to onnv_147Brian Behlendorf2010-08-261-1/+1
| | | | | This is the last official OpenSolaris tag before the public development tree was closed.
* Update core ZFS code from build 121 to build 141.Brian Behlendorf2010-05-281-38/+123
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* Rebase master to b105Brian Behlendorf2009-01-151-0/+12
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* Move the world out of /zfs/ and seperate out module build treeBrian Behlendorf2008-12-111-0/+627
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