mirror_zfs/include
Rob Norris 27e9cb5f80 ddt: cleanup the stats & histogram code
Both the API and the code were kinda mangled and I was really struggling
to follow it. The worst offender was the old ddt_stat_add(); after
fixing it up the rest of the changes are mostly knock-on effects and
targets of opportunity.

Note that the old ddt_stat_add() was safe against overflows - it could
produce crazy numbers, but the compiler wouldn't do anything stupid. The
assertions in ddt_stat_sub() go a lot of the way to protecting against
this; getting in a position where overflows are a problem is definitely
a programming error.

Also expanding ddt_stat_add() and ddt_histogram_empty() produces less
efficient assembly. I'm not bothered about this right now though; these
should not be hot functions, and if they are we'll optimise them later.
If we have to go back to the old form, we'll comment it like crazy.

Finally, I've removed the assertion that the bucket will never be
negative, as it will soon be possible to have entries with zero
refcounts: an entry for a block that is no longer on the pool, but is on
the log waiting to be synced out. It might be better to have a separate
bucket for these, since they're still using real space on disk, but
ultimately these stats are driving UI, and for now I've chosen to keep
them matching how they've looked in the past, as well as match the
operators mental model - pool usage is managed elsewhere.

Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <rob.norris@klarasystems.com>
Sponsored-by: Klara, Inc.
Sponsored-by: iXsystems, Inc.
Closes #15895
2024-08-16 12:02:56 -07:00
..
os Linux 6.11: add compat macro for page_mapping() 2024-08-13 17:47:18 -07:00
sys ddt: cleanup the stats & histogram code 2024-08-16 12:02:56 -07:00
.gitignore OpenZFS restructuring - move platform specific sources 2019-09-06 11:26:26 -07:00
cityhash.h libzfs: convert to -fvisibility=hidden 2021-06-03 13:17:55 -07:00
libnvpair.h nvpair: Constify string functions 2023-03-14 15:25:50 -07:00
libuutil_common.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
libuutil_impl.h libuutil: deobfuscate internal pointers 2022-11-03 09:57:05 -07:00
libuutil.h Cleanup: Remove unused uu_pname code 2022-09-19 17:33:52 -07:00
libzdb.h libzdb: Initial breakout of libzdb 2024-02-05 10:00:41 -08:00
libzfs_core.h ddt: add support for prefetching tables into the ARC 2024-07-26 09:16:18 -07:00
libzfs.h libzfs.h: Set ZFS_MAXPROPLEN and ZPOOL_MAXPROPLEN to ZAP_MAXVALUELEN 2024-08-08 15:23:40 -07:00
libzfsbootenv.h lib{efi,avl,share,tpool,zfs_core,zfsbootenv,zutil}: -fvisibility=hidden 2021-06-09 17:04:32 -07:00
libzutil.h Parallel pool import 2024-04-22 09:42:38 -07:00
Makefile.am ddt: split internal DDT API into separate header 2024-02-15 11:45:15 -08:00
thread_pool.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfeature_common.h ddt: add FDT feature and support for legacy and new on-disk formats 2024-08-16 11:58:59 -07:00
zfs_comutil.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_deleg.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_fletcher.h Drop lying to the compiler in the fletcher4 code 2023-03-24 10:29:19 -07:00
zfs_namecheck.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_prop.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00