Add support for POSIX_FADV_DONTNEED

For now make it only evict the specified data from the dbuf cache.
Even though dbuf cache is small, this may still reduce eviction of
more useful data from there, and slightly accelerate ARC evictions
by making the blocks there evictable a bit sooner.

On FreeBSD this also adds support for POSIX_FADV_NOREUSE, since the
kernel translates it into POSIX_FADV_DONTNEED after every read/write.
This is not as efficient as it could be for ZFS, but that is the only
way FreeBSD kernel allows to handle POSIX_FADV_NOREUSE now.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Alexander Motin <alexander.motin@TrueNAS.com>
Closes #18399
This commit is contained in:
Alexander Motin
2026-04-07 11:56:54 -04:00
committed by Tony Hutter
parent 6f14581e1a
commit 4bb7592745
9 changed files with 169 additions and 4 deletions
+2
View File
@@ -963,6 +963,8 @@ void dmu_prefetch_by_dnode(dnode_t *dn, int64_t level, uint64_t offset,
void dmu_prefetch_dnode(objset_t *os, uint64_t object, enum zio_priority pri);
int dmu_prefetch_wait(objset_t *os, uint64_t object, uint64_t offset,
uint64_t size);
void dmu_evict_range(objset_t *os, uint64_t object, uint64_t offset,
uint64_t len);
typedef struct dmu_object_info {
/* All sizes are in bytes unless otherwise indicated. */