mirror_zfs/module
Alexander Motin e82e68400a DMU: Do not pre-read holes during write
dmu_tx_check_ioerr() pre-reads blocks that are going to be dirtied
as part of transaction to both prefetch them and check for errors.
But it makes no sense to do it for holes, since there are no disk
reads to prefetch and there can be no errors.  On the other side
those blocks are anonymous, and they are freed immediately by the
dbuf_rele() without even being put into dbuf cache, so we just
burn CPU time on decompression and overheads and get absolutely
no result at the end.

Use of dbuf_hold_impl() with fail_sparse parameter allows to skip
the extra work, and on my tests with sequential 8KB writes to empty
ZVOL with 32KB blocks shows throughput increase from 1.7 to 2GB/s.

Reviewed-by: Brian Atkinson <batkinson@lanl.gov>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by:	Alexander Motin <mav@FreeBSD.org>
Sponsored by:	iXsystems, Inc.
Closes #15371
2023-11-08 12:15:41 -08:00
..
avl Suppress Clang Static Analyzer false positive in the AVL tree code. 2023-03-08 13:51:21 -08:00
icp Add BTI landing pads to the AArch64 SHA2 assembly 2023-10-04 12:36:21 -07:00
lua Add loongarch64 support 2023-04-25 16:05:45 -07:00
nvpair nvpair: Constify string functions 2023-03-14 15:25:50 -07:00
os Linux 6.6 compat: fsync_bdev() has been removed in favor of sync_blockdev() 2023-11-08 12:15:41 -08:00
unicode Illumos #15286: do_composition() needs sign awareness 2023-01-05 11:16:21 -08:00
zcommon set autotrim default to 'off' everywhere 2023-07-21 16:35:12 -07:00
zfs DMU: Do not pre-read holes during write 2023-11-08 12:15:41 -08:00
zstd Resolve WS-2021-0184 vulnerability in zstd 2023-02-02 15:12:51 -08:00
.gitignore FreeBSD: Ignore symlink to i386 includes 2022-08-02 16:34:23 -07:00
Kbuild.in linux: implement filesystem-side copy/clone functions 2023-07-26 08:46:58 -07:00
Makefile.bsd Finally drop long disabled vdev cache. 2023-06-09 12:40:55 -07:00
Makefile.in check-zstd-symbols: also ignore __pfx_ symbols 2023-09-19 08:52:06 -07:00