Matthew Ahrens 3c42c9ed84 Clean up OS-specific ARC and kmem code ... OS-specific code (e.g. under `module/os/linux`) does not need to share its code structure with any other operating systems. In particular, the ARC and kmem code need not be similar to the code in illumos, because we won't be syncing this OS-specific code between operating systems. For example, if/when illumos support is added to the common repo, we would add a file `module/os/illumos/zfs/arc_os.c` for the illumos versions of this code. Therefore, we can simplify the code in the OS-specific ARC and kmem routines. These changes do not impact system behavior, they are purely code cleanup. The changes are: Arenas are not used on Linux or FreeBSD (they are always `NULL`), so `heap_arena`, `zio_arena`, and `zio_alloc_arena` can be removed, along with code that uses them. In `arc_available_memory()`: * `desfree` is unused, remove it * rename `freemem` to avoid conflict with pre-existing `#define` * remove checks related to arenas * use units of bytes, rather than converting from bytes to pages and then back to bytes `SPL_KMEM_CACHE_REAP` is unused, remove it. `skc_reap` is unused, remove it. The `count` argument to `spl_kmem_cache_reap_now()` is unused, remove it. `vmem_size()` and associated type and macros are unused, remove them. In `arc_memory_throttle()`, use a less confusing variable name to store the result of `arc_free_memory()`. Reviewed-by: George Wilson <gwilson@delphix.com> Reviewed-by: Pavel Zakharov <pavel.zakharov@delphix.com> Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Reviewed-by: Ryan Moeller <ryan@ixsystems.com> Signed-off-by: Matthew Ahrens <mahrens@delphix.com> Closes #10499		2020-06-29 09:01:07 -07:00
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spl	Clean up OS-specific ARC and kmem code	2020-06-29 09:01:07 -07:00
zfs	Clean up OS-specific ARC and kmem code	2020-06-29 09:01:07 -07:00