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Cleanup: 64-bit kernel module parameters should use fixed width types

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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
This commit is contained in:
Richard Yao
2022-10-03 15:06:54 -04:00
committed by Brian Behlendorf
parent ff7a0a108f
commit ab8d9c1783
49 changed files with 338 additions and 286 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/sys/arc_impl.h
+3 -3
View File
@@ -985,8 +985,8 @@ extern arc_state_t ARC_mfu;
extern arc_state_t ARC_mru;
extern uint_t zfs_arc_pc_percent;
extern uint_t arc_lotsfree_percent;
extern unsigned long zfs_arc_min;
extern unsigned long zfs_arc_max;
extern uint64_t zfs_arc_min;
extern uint64_t zfs_arc_max;
extern void arc_reduce_target_size(int64_t to_free);
extern boolean_t arc_reclaim_needed(void);
@@ -1003,7 +1003,7 @@ extern void arc_tuning_update(boolean_t);
extern void arc_register_hotplug(void);
extern void arc_unregister_hotplug(void);
extern int param_set_arc_long(ZFS_MODULE_PARAM_ARGS);
extern int param_set_arc_u64(ZFS_MODULE_PARAM_ARGS);
extern int param_set_arc_int(ZFS_MODULE_PARAM_ARGS);
extern int param_set_arc_min(ZFS_MODULE_PARAM_ARGS);
extern int param_set_arc_max(ZFS_MODULE_PARAM_ARGS);
include/sys/dmu_zfetch.h
+1 -1
View File
@@ -36,7 +36,7 @@
extern "C" {
#endif
extern unsigned long zfetch_array_rd_sz;
extern uint64_t zfetch_array_rd_sz;
struct dnode; /* so we can reference dnode */
include/sys/dsl_deadlist.h
+1 -1
View File
@@ -84,7 +84,7 @@ typedef struct livelist_condense_entry {
boolean_t cancelled;
} livelist_condense_entry_t;
extern unsigned long zfs_livelist_max_entries;
extern uint64_t zfs_livelist_max_entries;
extern int zfs_livelist_min_percent_shared;
typedef int deadlist_iter_t(void *args, dsl_deadlist_entry_t *dle);
include/sys/dsl_pool.h
+4 -4
View File
@@ -57,13 +57,13 @@ struct dsl_scan;
struct dsl_crypto_params;
struct dsl_deadlist;
extern unsigned long zfs_dirty_data_max;
extern unsigned long zfs_dirty_data_max_max;
extern unsigned long zfs_wrlog_data_max;
extern uint64_t zfs_dirty_data_max;
extern uint64_t zfs_dirty_data_max_max;
extern uint64_t zfs_wrlog_data_max;
extern uint_t zfs_dirty_data_max_percent;
extern uint_t zfs_dirty_data_max_max_percent;
extern uint_t zfs_delay_min_dirty_percent;
extern unsigned long zfs_delay_scale;
extern uint64_t zfs_delay_scale;
/* These macros are for indexing into the zfs_all_blkstats_t. */
#define DMU_OT_DEFERRED DMU_OT_NONE
include/sys/mmp.h
+1 -1
View File
@@ -64,7 +64,7 @@ extern void mmp_signal_all_threads(void);
/* Global tuning */
extern int param_set_multihost_interval(ZFS_MODULE_PARAM_ARGS);
extern ulong_t zfs_multihost_interval;
extern uint64_t zfs_multihost_interval;
extern uint_t zfs_multihost_fail_intervals;
extern uint_t zfs_multihost_import_intervals;
include/sys/spa.h
+3 -3
View File
@@ -1218,9 +1218,9 @@ int param_set_deadman_failmode(ZFS_MODULE_PARAM_ARGS);
extern spa_mode_t spa_mode_global;
extern int zfs_deadman_enabled;
extern unsigned long zfs_deadman_synctime_ms;
extern unsigned long zfs_deadman_ziotime_ms;
extern unsigned long zfs_deadman_checktime_ms;
extern uint64_t zfs_deadman_synctime_ms;
extern uint64_t zfs_deadman_ziotime_ms;
extern uint64_t zfs_deadman_checktime_ms;
extern kmem_cache_t *zio_buf_cache[];
extern kmem_cache_t *zio_data_buf_cache[];
include/sys/vdev_impl.h
+2 -2
View File
@@ -649,8 +649,8 @@ uint64_t vdev_best_ashift(uint64_t logical, uint64_t a, uint64_t b);
/*
* Vdev ashift optimization tunables
*/
extern uint64_t zfs_vdev_min_auto_ashift;
extern uint64_t zfs_vdev_max_auto_ashift;
extern uint_t zfs_vdev_min_auto_ashift;
extern uint_t zfs_vdev_max_auto_ashift;
int param_set_min_auto_ashift(ZFS_MODULE_PARAM_ARGS);
int param_set_max_auto_ashift(ZFS_MODULE_PARAM_ARGS);
include/sys/zcp.h
+2 -2
View File
@@ -33,8 +33,8 @@ extern "C" {
#define ZCP_RUN_INFO_KEY "runinfo"
extern unsigned long zfs_lua_max_instrlimit;
extern unsigned long zfs_lua_max_memlimit;
extern uint64_t zfs_lua_max_instrlimit;
extern uint64_t zfs_lua_max_memlimit;
int zcp_argerror(lua_State *, int, const char *, ...);
include/sys/zfs_ioctl_impl.h
+1 -1
View File
@@ -24,7 +24,7 @@
#define _ZFS_IOCTL_IMPL_H_
extern kmutex_t zfsdev_state_lock;
extern unsigned long zfs_max_nvlist_src_size;
extern uint64_t zfs_max_nvlist_src_size;
typedef int zfs_ioc_legacy_func_t(zfs_cmd_t *);
typedef int zfs_ioc_func_t(const char *, nvlist_t *, nvlist_t *);