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* Fast Clone DeletionSara Hartse2019-07-261-0/+2
| | | | | | | | | | | | | | | | | | | | | Deleting a clone requires finding blocks are clone-only, not shared with the snapshot. This was done by traversing the entire block tree which results in a large performance penalty for sparsely written clones. This is new method keeps track of clone blocks when they are modified in a "Livelist" so that, when it’s time to delete, the clone-specific blocks are already at hand. We see performance improvements because now deletion work is proportional to the number of clone-modified blocks, not the size of the original dataset. Reviewed-by: Sean Eric Fagan <[email protected]> Reviewed-by: Matt Ahrens <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Serapheim Dimitropoulos <[email protected]> Signed-off-by: Sara Hartse <[email protected]> Closes #8416
* Serialize ZTHR operations to eliminate racesSerapheim Dimitropoulos2019-01-131-19/+3
| | | | | | | | | | | Adds a new lock for serializing operations on zthrs. The commit also includes some code cleanup and refactoring. Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Tom Caputi <[email protected]> Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Serapheim Dimitropoulos <[email protected]> Closes #8229
* OpenZFS 9284 - arc_reclaim_thread has 2 jobsBrad Lewis2018-12-261-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Following the fix for 9018 (Replace kmem_cache_reap_now() with kmem_cache_reap_soon), the arc_reclaim_thread() no longer blocks while reaping. However, the code is still confusing and error-prone, because this thread has two responsibilities. We should instead separate this into two threads each with their own responsibility: 1. keep `arc_size` under `arc_c`, by calling `arc_adjust()`, which improves `arc_is_overflowing()` 2. keep enough free memory in the system, by calling `arc_kmem_reap_now()` plus `arc_shrink()`, which improves `arc_available_memory()`. Furthermore, we can use the zthr infrastructure to separate the "should we do something" from "do it" parts of the logic, and normalize the start up / shut down of the threads. Authored by: Brad Lewis <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Paul Dagnelie <[email protected]> Reviewed by: Dan McDonald <[email protected]> Reviewed by: Tim Kordas <[email protected]> Reviewed by: Tim Chase <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Ported-by: Brad Lewis <[email protected]> Signed-off-by: Brad Lewis <[email protected]> OpenZFS-issue: https://www.illumos.org/issues/9284 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/de753e34f9 Closes #8165
* OpenZFS 9166 - zfs storage pool checkpointSerapheim Dimitropoulos2018-06-261-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Details about the motivation of this feature and its usage can be found in this blogpost: https://sdimitro.github.io/post/zpool-checkpoint/ A lightning talk of this feature can be found here: https://www.youtube.com/watch?v=fPQA8K40jAM Implementation details can be found in big block comment of spa_checkpoint.c Side-changes that are relevant to this commit but not explained elsewhere: * renames members of "struct metaslab trees to be shorter without losing meaning * space_map_{alloc,truncate}() accept a block size as a parameter. The reason is that in the current state all space maps that we allocate through the DMU use a global tunable (space_map_blksz) which defauls to 4KB. This is ok for metaslab space maps in terms of bandwirdth since they are scattered all over the disk. But for other space maps this default is probably not what we want. Examples are device removal's vdev_obsolete_sm or vdev_chedkpoint_sm from this review. Both of these have a 1:1 relationship with each vdev and could benefit from a bigger block size. Porting notes: * The part of dsl_scan_sync() which handles async destroys has been moved into the new dsl_process_async_destroys() function. * Remove "VERIFY(!(flags & FWRITE))" in "kernel.c" so zhack can write to block device backed pools. * ZTS: * Fix get_txg() in zpool_sync_001_pos due to "checkpoint_txg". * Don't use large dd block sizes on /dev/urandom under Linux in checkpoint_capacity. * Adopt Delphix-OS's setting of 4 (spa_asize_inflation = SPA_DVAS_PER_BP + 1) for the checkpoint_capacity test to speed its attempts to fill the pool * Create the base and nested pools with sync=disabled to speed up the "setup" phase. * Clear labels in test pool between checkpoint tests to avoid duplicate pool issues. * The import_rewind_device_replaced test has been marked as "known to fail" for the reasons listed in its DISCLAIMER. * New module parameters: zfs_spa_discard_memory_limit, zfs_remove_max_bytes_pause (not documented - debugging only) vdev_max_ms_count (formerly metaslabs_per_vdev) vdev_min_ms_count Authored by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: John Kennedy <[email protected]> Reviewed by: Dan Kimmel <[email protected]> Reviewed by: Brian Behlendorf <[email protected]> Approved by: Richard Lowe <[email protected]> Ported-by: Tim Chase <[email protected]> Signed-off-by: Tim Chase <[email protected]> OpenZFS-issue: https://illumos.org/issues/9166 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/7159fdb8 Closes #7570
* OpenZFS 9079 - race condition in starting and ending condensing thread for ↵Serapheim Dimitropoulos2018-04-141-0/+52
indirect vdevs The timeline of the race condition is the following: [1] Thread A is about to finish condesing the first vdev in spa_condense_indirect_thread(), so it calls the spa_condense_indirect_complete_sync() sync task which sets the spa_condensing_indirect field to NULL. Waiting for the sync task to finish, thread A sleeps until the txg is done. When this happens, thread A will acquire spa_async_lock and set spa_condense_thread to NULL. [2] While thread A waits for the txg to finish, thread B which is running spa_sync() checks whether it should condense the second vdev in vdev_indirect_should_condense() by checking the spa_condensing_indirect field which was set to NULL by spa_condense_indirect_thread() from thread A. So it goes on and tries to spawn a new condensing thread in spa_condense_indirect_start_sync() and the aforementioned assertions fails because thread A has not set spa_condense_thread to NULL (which is basically the last thing it does before returning). The main issue here is that we rely on both spa_condensing_indirect and spa_condense_thread to signify whether a condensing thread is running. Ideally we would only use one throughout the codebase. In addition, for managing spa_condense_thread we currently use spa_async_lock which basically tights condensing to scrubing when it comes to pausing and resuming those actions during spa export. This commit introduces the ZTHR infrastructure, which is basically threads created during spa_load()/spa_create() and exist until we export or destroy the pool. ZTHRs sleep the majority of the time, until they are notified to wake up and do some predefined type of work. In the context of the current bug, a zthr to does the condensing of indirect mappings replacing the older code that used bare kthreads. When a pool is created, the condensing zthr is spawned but sleeps right away, until it is awaken by a signal from spa_sync(). If an existing pool is loaded, the condensing zthr looks if there is anything to condense before going to sleep, in case we were condensing mappings in the pool before it got exported. The benefits of this solution are the following: - The current bug is fixed - spa_condensing_indirect is the sole indicator of whether we are currently condensing or not - condensing is more decoupled from the spa_async_thread related functionality. As a final note, this commit also sets up the path on upstreaming other features that use the ZTHR code like zpool checkpoint and fast clone deletion. Authored by: Serapheim Dimitropoulos <[email protected]> Reviewed by: Matt Ahrens <[email protected]> Reviewed by: Pavel Zakharov <[email protected]> Approved by: Hans Rosenfeld <[email protected]> Ported-by: Tim Chase <[email protected]> OpenZFS-issue: https://illumos.org/issues/9079 OpenZFS-commit: https://github.com/openzfs/openzfs/commit/3dc606ee Closes #6900