MFC r286763: 5497 lock contention on arcs_mtx

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Prakash Surya <prakash.surya@delphix.com>

illumos/illumos-gate@244781f10dcd82684fd8163c016540667842f203

This patch attempts to reduce lock contention on the current arc_state_t
mutexes. These mutexes are used liberally to protect the number of LRU
lists within the ARC (e.g. ARC_mru, ARC_mfu, etc). The granularity at
which these locks are acquired has been shown to greatly affect the
performance of highly concurrent, cached workloads.

MFC r286705: 5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=

Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Author: Paul Dagnelie <pcd@delphix.com>

While running 'zfs recv' we noticed that every 128th 8K block required a
read. We were seeing that restore_write() was calling dmu_tx_hold_write()
and the indirect block was not cached. We should prefetch upcoming indirect
blocks to avoid having to go to disk and blocking the restore_write().

Allow an incremental send stream to be received as a clone, even if the
stream does not mark it as a clone.

MFC r268075: MFV r267565:

4757 ZFS embedded-data block pointers ("zero block compression")
4913 zfs release should not be subject to space checks

MFC r260183: MFV r260154 + 260182:

4369 implement zfs bookmarks
4368 zfs send filesystems from readonly pools

Illumos/illumos-gate@78f171005391b928aaf1642b3206c534ed644332

MFC r258717: MFV r258371,r258372: 4101 metaslab_debug should allow for
fine-grained control

MFC r258743: drop ZUT_OBJ

MFC r286763: 5497 lock contention on arcs_mtx

Reviewed by: George Wilson <george.wilson@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Reviewed by: Richard Elling <richard.elling@richardelling.com>
Approved by: Dan McDonald <danmcd@omniti.com>
Author: Prakash Surya <prakash.surya@delphix.com>

illumos/illumos-gate@244781f10dcd82684fd8163c016540667842f203

This patch attempts to reduce lock contention on the current arc_state_t
mutexes. These mutexes are used liberally to protect the number of LRU
lists within the ARC (e.g. ARC_mru, ARC_mfu, etc). The granularity at
which these locks are acquired has been shown to greatly affect the
performance of highly concurrent, cached workloads.

MFC r286705: 5960 zfs recv should prefetch indirect blocks
5925 zfs receive -o origin=

Reviewed by: Prakash Surya <prakash.surya@delphix.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Author: Paul Dagnelie <pcd@delphix.com>

While running 'zfs recv' we noticed that every 128th 8K block required a
read. We were seeing that restore_write() was calling dmu_tx_hold_write()
and the indirect block was not cached. We should prefetch upcoming indirect
blocks to avoid having to go to disk and blocking the restore_write().

Allow an incremental send stream to be received as a clone, even if the
stream does not mark it as a clone.

MFC r268075: MFV r267565:

4757 ZFS embedded-data block pointers ("zero block compression")
4913 zfs release should not be subject to space checks

MFC r260183: MFV r260154 + 260182:

4369 implement zfs bookmarks
4368 zfs send filesystems from readonly pools

Illumos/illumos-gate@78f171005391b928aaf1642b3206c534ed644332

MFC r258717: MFV r258371,r258372: 4101 metaslab_debug should allow for
fine-grained control

MFC r258743: drop ZUT_OBJ