Linux kernel shrinker in the context of null/root memcg does not scan
dentry and inode caches added by a task running in non-root memcg. For
ZFS this means that dnode cache routinely overflows, evicting valuable
meta/data and putting additional memory pressure on the system.
This patch restores zfs_prune_aliases as fallback when the kernel
shrinker does nothing, enabling zfs to actually free dnodes. Moreover,
it (indirectly) calls arc_evict when dnode_size > dnode_limit.
Reviewed-by: Rob Norris <robn@despairlabs.com>
Reviewed-by: Alexander Motin <mav@FreeBSD.org>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Gionatan Danti <g.danti@assyoma.it>
Closes#17487Closes#17542
a7a144e655