mirror_zfs/include/sys
Richard Yao ab8d9c1783 Cleanup: 64-bit kernel module parameters should use fixed width types
Various module parameters such as `zfs_arc_max` were originally
`uint64_t` on OpenSolaris/Illumos, but were changed to `unsigned long`
for Linux compatibility because Linux's kernel default module parameter
implementation did not support 64-bit types on 32-bit platforms. This
caused problems when porting OpenZFS to Windows because its LLP64 memory
model made `unsigned long` a 32-bit type on 64-bit, which created the
undesireable situation that parameters that should accept 64-bit values
could not on 64-bit Windows.

Upon inspection, it turns out that the Linux kernel module parameter
interface is extensible, such that we are allowed to define our own
types. Rather than maintaining the original type change via hacks to to
continue shrinking module parameters on 32-bit Linux, we implement
support for 64-bit module parameters on Linux.

After doing a review of all 64-bit kernel parameters (found via the man
page and also proposed changes by Andrew Innes), the kernel module
parameters fell into a few groups:

Parameters that were originally 64-bit on Illumos:

 * dbuf_cache_max_bytes
 * dbuf_metadata_cache_max_bytes
 * l2arc_feed_min_ms
 * l2arc_feed_secs
 * l2arc_headroom
 * l2arc_headroom_boost
 * l2arc_write_boost
 * l2arc_write_max
 * metaslab_aliquot
 * metaslab_force_ganging
 * zfetch_array_rd_sz
 * zfs_arc_max
 * zfs_arc_meta_limit
 * zfs_arc_meta_min
 * zfs_arc_min
 * zfs_async_block_max_blocks
 * zfs_condense_max_obsolete_bytes
 * zfs_condense_min_mapping_bytes
 * zfs_deadman_checktime_ms
 * zfs_deadman_synctime_ms
 * zfs_initialize_chunk_size
 * zfs_initialize_value
 * zfs_lua_max_instrlimit
 * zfs_lua_max_memlimit
 * zil_slog_bulk

Parameters that were originally 32-bit on Illumos:

 * zfs_per_txg_dirty_frees_percent

Parameters that were originally `ssize_t` on Illumos:

 * zfs_immediate_write_sz

Note that `ssize_t` is `int32_t` on 32-bit and `int64_t` on 64-bit. It
has been upgraded to 64-bit.

Parameters that were `long`/`unsigned long` because of Linux/FreeBSD
influence:

 * l2arc_rebuild_blocks_min_l2size
 * zfs_key_max_salt_uses
 * zfs_max_log_walking
 * zfs_max_logsm_summary_length
 * zfs_metaslab_max_size_cache_sec
 * zfs_min_metaslabs_to_flush
 * zfs_multihost_interval
 * zfs_unflushed_log_block_max
 * zfs_unflushed_log_block_min
 * zfs_unflushed_log_block_pct
 * zfs_unflushed_max_mem_amt
 * zfs_unflushed_max_mem_ppm

New parameters that do not exist in Illumos:

 * l2arc_trim_ahead
 * vdev_file_logical_ashift
 * vdev_file_physical_ashift
 * zfs_arc_dnode_limit
 * zfs_arc_dnode_limit_percent
 * zfs_arc_dnode_reduce_percent
 * zfs_arc_meta_limit_percent
 * zfs_arc_sys_free
 * zfs_deadman_ziotime_ms
 * zfs_delete_blocks
 * zfs_history_output_max
 * zfs_livelist_max_entries
 * zfs_max_async_dedup_frees
 * zfs_max_nvlist_src_size
 * zfs_rebuild_max_segment
 * zfs_rebuild_vdev_limit
 * zfs_unflushed_log_txg_max
 * zfs_vdev_max_auto_ashift
 * zfs_vdev_min_auto_ashift
 * zfs_vnops_read_chunk_size
 * zvol_max_discard_blocks

Rather than clutter the lists with commentary, the module parameters
that need comments are repeated below.

A few parameters were defined in Linux/FreeBSD specific code, where the
use of ulong/long is not an issue for portability, so we leave them
alone:

 * zfs_delete_blocks
 * zfs_key_max_salt_uses
 * zvol_max_discard_blocks

The documentation for a few parameters was found to be incorrect:

 * zfs_deadman_checktime_ms - incorrectly documented as int
 * zfs_delete_blocks - not documented as Linux only
 * zfs_history_output_max - incorrectly documented as int
 * zfs_vnops_read_chunk_size - incorrectly documented as long
 * zvol_max_discard_blocks - incorrectly documented as ulong

The documentation for these has been fixed, alongside the changes to
document the switch to fixed width types.

In addition, several kernel module parameters were percentages or held
ashift values, so being 64-bit never made sense for them. They have been
downgraded to 32-bit:

 * vdev_file_logical_ashift
 * vdev_file_physical_ashift
 * zfs_arc_dnode_limit_percent
 * zfs_arc_dnode_reduce_percent
 * zfs_arc_meta_limit_percent
 * zfs_per_txg_dirty_frees_percent
 * zfs_unflushed_log_block_pct
 * zfs_vdev_max_auto_ashift
 * zfs_vdev_min_auto_ashift

Of special note are `zfs_vdev_max_auto_ashift` and
`zfs_vdev_min_auto_ashift`, which were already defined as `uint64_t`,
and passed to the kernel as `ulong`. This is inherently buggy on big
endian 32-bit Linux, since the values would not be written to the
correct locations. 32-bit FreeBSD was unaffected because its sysctl code
correctly treated this as a `uint64_t`.

Lastly, a code comment suggests that `zfs_arc_sys_free` is
Linux-specific, but there is nothing to indicate to me that it is
Linux-specific. Nothing was done about that.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Jorgen Lundman <lundman@lundman.net>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Original-patch-by: Andrew Innes <andrew.c12@gmail.com>
Original-patch-by: Jorgen Lundman <lundman@lundman.net>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13984
Closes #14004
2022-10-13 10:03:29 -07:00
..
crypto Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
fm Cleanup: Specify unsignedness on things that should not be signed 2022-09-27 16:42:41 -07:00
fs Enforce "-F" flag on resuming recv of full/newfs on existing dataset 2022-09-27 16:34:27 -07:00
lua autoconf: single-step includes 2022-05-10 10:18:51 -07:00
sysevent zed: Fix config_sync autoexpand flood 2022-09-08 10:32:30 -07:00
zstd Unbreak zstd build on sparc64 2022-05-25 09:18:49 -07:00
abd_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
abd.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
aggsum.h More aggsum optimizations 2021-06-07 09:02:47 -07:00
arc_impl.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
arc.h Cleanup: Specify unsignedness on things that should not be signed 2022-09-27 16:42:41 -07:00
avl_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
avl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
bitops.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
blake3.h Fix BLAKE3 tuneable and module loading on Linux and FreeBSD 2022-09-16 14:25:53 -07:00
blkptr.h OpenZFS 8067 - zdb should be able to dump literal embedded block pointer 2017-07-07 11:28:01 -07:00
bplist.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
bpobj.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
bptree.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
bqueue.h zfs recv hangs if max recordsize is less than received recordsize 2022-09-16 13:52:25 -07:00
btree.h Several B-tree optimizations 2022-06-24 13:55:58 -07:00
dataset_kstats.h Add support for per dataset zil stats and use wmsum counters 2022-07-20 17:14:06 -07:00
dbuf.h Dynamically size dbuf hash mutex array 2022-09-22 12:59:56 -07:00
ddt.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_objset.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_recv.h Implement a new type of zfs receive: corrective receive (-c) 2022-07-28 15:52:46 -07:00
dmu_redact.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_send.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_traverse.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_tx.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dmu_zfetch.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
dmu.h Fix double const qualifier declarations 2022-09-30 15:34:39 -07:00
dnode.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dsl_bookmark.h Remaining {=> const} char|void *tag 2022-06-29 14:08:59 -07:00
dsl_crypt.h Fix zpool status in case of unloaded keys 2022-08-22 17:42:01 -07:00
dsl_dataset.h Add zfs.sync.snapshot_rename 2022-09-02 13:31:19 -07:00
dsl_deadlist.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
dsl_deleg.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dsl_destroy.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dsl_dir.h Add DD_FIELD string for snapshots_changed property 2022-09-02 13:33:50 -07:00
dsl_pool.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
dsl_prop.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dsl_scan.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dsl_synctask.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
dsl_userhold.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
edonr.h OpenZFS 4185 - add new cryptographic checksums to ZFS: SHA-512, Skein, Edon-R 2016-10-03 14:51:15 -07:00
efi_partition.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
frame.h Linux 5.10 compat: frame.h renamed objtool.h 2020-11-02 22:01:10 +00:00
hkdf.h Encryption patch follow-up 2017-10-11 16:54:48 -04:00
metaslab_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
metaslab.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
mmp.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
mntent.h Expose ZFS dataset case sensitivity setting via sb_opts 2022-07-14 10:38:16 -07:00
mod.h linux: module: weld all but spl.ko into zfs.ko 2022-04-20 13:28:24 -07:00
multilist.h Re-embed multilist_t storage 2021-06-10 10:42:31 -06:00
nvpair_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
nvpair.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
objlist.h Implement Redacted Send/Receive 2019-06-19 09:48:12 -07:00
pathname.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
qat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
range_tree.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
rrwlock.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
sa_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
sa.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
skein.h OpenZFS 4185 - add new cryptographic checksums to ZFS: SHA-512, Skein, Edon-R 2016-10-03 14:51:15 -07:00
spa_checkpoint.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
spa_checksum.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
spa_impl.h Cleanup: Specify unsignedness on things that should not be signed 2022-09-27 16:42:41 -07:00
spa_log_spacemap.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
spa.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
space_map.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
space_reftree.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
sysevent.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
txg_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
txg.h Cleanup: Specify unsignedness on things that should not be signed 2022-09-27 16:42:41 -07:00
u8_textprep_data.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
u8_textprep.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
uberblock_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
uberblock.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
uio_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
unique.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
uuid.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_disk.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_draid.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_file.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_impl.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
vdev_indirect_births.h OpenZFS 7614, 9064 - zfs device evacuation/removal 2018-04-14 12:16:17 -07:00
vdev_indirect_mapping.h OpenZFS 7614, 9064 - zfs device evacuation/removal 2018-04-14 12:16:17 -07:00
vdev_initialize.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_raidz_impl.h Cleanup Raid-Z Typo fixes 2022-09-06 09:43:21 -07:00
vdev_raidz.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_rebuild.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev_removal.h Cleanup: Specify unsignedness on things that should not be signed 2022-09-27 16:42:41 -07:00
vdev_trim.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
vdev.h zed: mark disks as REMOVED when they are removed 2022-09-28 09:48:46 -07:00
xvattr.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zap_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zap_leaf.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zap.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zcp_global.h OpenZFS 7431 - ZFS Channel Programs 2018-02-08 15:28:18 -08:00
zcp_iter.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zcp_prop.h OpenZFS 7431 - ZFS Channel Programs 2018-02-08 15:28:18 -08:00
zcp_set.h Support setting user properties in a channel program 2020-02-14 13:41:42 -08:00
zcp.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
zfeature.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_acl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_bootenv.h zfs label bootenv should store data as nvlist 2020-09-15 15:42:27 -07:00
zfs_chksum.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_context.h Reduce false positives from Static Analyzers 2022-09-30 15:30:12 -07:00
zfs_debug.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_delay.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_file.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_fuid.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_ioctl_impl.h Cleanup: 64-bit kernel module parameters should use fixed width types 2022-10-13 10:03:29 -07:00
zfs_ioctl.h DMU_BACKUP_FEATURE: indicate that bit 28 and 29 are reserved 2022-09-27 16:55:32 -07:00
zfs_onexit.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_project.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_quota.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_racct.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_ratelimit.h Change checksum & IO delay ratelimit values 2018-03-04 17:34:51 -08:00
zfs_refcount.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_rlock.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_sa.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_stat.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_sysfs.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_vfsops.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_vnops.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zfs_znode.h zfs_enter rework 2022-09-16 13:36:47 -07:00
zil_impl.h Add support for per dataset zil stats and use wmsum counters 2022-07-20 17:14:06 -07:00
zil.h Add support for per dataset zil stats and use wmsum counters 2022-07-20 17:14:06 -07:00
zio_checksum.h Fix double const qualifier declarations 2022-09-30 15:34:39 -07:00
zio_compress.h Fix double const qualifier declarations 2022-09-30 15:34:39 -07:00
zio_crypt.h Enable -Wwrite-strings 2022-06-29 14:08:54 -07:00
zio_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zio_priority.h Add device rebuild feature 2020-07-03 11:05:50 -07:00
zio.h Implement a new type of zfs receive: corrective receive (-c) 2022-07-28 15:52:46 -07:00
zrlock.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zthr.h Avoid memory allocations in the ARC eviction thread 2022-01-21 10:28:13 -08:00
zvol_impl.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00
zvol.h Replace dead opensolaris.org license link 2022-07-11 14:16:13 -07:00