1#!/bin/ksh -p
2#
3# CDDL HEADER START
4#
5# This file and its contents are supplied under the terms of the
6# Common Development and Distribution License ("CDDL"), version 1.0.
7# You may only use this file in accordance with the terms of version
8# 1.0 of the CDDL.
9#
10# A full copy of the text of the CDDL should have accompanied this
11# source.  A copy of the CDDL is also available via the Internet at
12# http://www.illumos.org/license/CDDL.
13#
14# CDDL HEADER END
15#
16
17#
18# Copyright (c) 2020, George Amanakis. All rights reserved.
19#
20
21. $STF_SUITE/include/libtest.shlib
22. $STF_SUITE/tests/functional/l2arc/l2arc.cfg
23
24#
25# DESCRIPTION:
26#	l2arc_mfuonly does not cache MRU buffers
27#
28# STRATEGY:
29#	1. Set l2arc_mfuonly=yes
30#	2. Create pool with a cache device.
31#	3. Create a random file in that pool, smaller than the cache device
32#		and random read for 10 sec.
33#	4. Export and re-import the pool. This is necessary as some MFU ghost
34#		buffers with prefetch status may transition to MRU eventually.
35#		By re-importing the pool the l2 arcstats reflect the ARC state
36#		of L2ARC buffers upon their caching in L2ARC.
37#	5. Verify l2arc_mru_asize is 0.
38#
39
40verify_runnable "global"
41
42command -v fio > /dev/null || log_unsupported "fio missing"
43
44log_assert "l2arc_mfuonly does not cache MRU buffers."
45
46function cleanup
47{
48	if poolexists $TESTPOOL ; then
49		destroy_pool $TESTPOOL
50	fi
51
52	log_must set_tunable32 L2ARC_NOPREFETCH $noprefetch
53	log_must set_tunable32 L2ARC_MFUONLY $mfuonly
54	log_must set_tunable32 PREFETCH_DISABLE $zfsprefetch
55}
56log_onexit cleanup
57
58# L2ARC_NOPREFETCH is set to 1 as some prefetched buffers may
59# transition to MRU.
60typeset noprefetch=$(get_tunable L2ARC_NOPREFETCH)
61log_must set_tunable32 L2ARC_NOPREFETCH 1
62
63typeset mfuonly=$(get_tunable L2ARC_MFUONLY)
64log_must set_tunable32 L2ARC_MFUONLY 1
65
66typeset zfsprefetch=$(get_tunable PREFETCH_DISABLE)
67log_must set_tunable32 PREFETCH_DISABLE 1
68
69typeset fill_mb=800
70typeset cache_sz=$(( 1.4 * $fill_mb ))
71export FILE_SIZE=$(( floor($fill_mb / $NUMJOBS) ))M
72
73log_must truncate -s ${cache_sz}M $VDEV_CACHE
74
75typeset log_blk_start=$(get_arcstat l2_log_blk_writes)
76
77log_must zpool create -f $TESTPOOL $VDEV cache $VDEV_CACHE
78
79log_must fio $FIO_SCRIPTS/mkfiles.fio
80log_must fio $FIO_SCRIPTS/random_reads.fio
81
82log_must zpool export $TESTPOOL
83log_must zpool import -N -d $VDIR $TESTPOOL
84
85# Regardless of l2arc_noprefetch, some MFU buffers might be evicted
86# from ARC, accessed later on as prefetches and transition to MRU as
87# prefetches.
88# If accessed again they are counted as MRU and the l2arc_mru_asize arcstat
89# will not be 0 (mentioned also in zfs.4)
90# For the purposes of this test we mitigate this by disabling (predictive)
91# ZFS prefetches with zfs_prefetch_disable=1.
92log_must test $(get_arcstat l2_mru_asize) -eq 0
93
94log_must zpool destroy -f $TESTPOOL
95
96log_pass "l2arc_mfuonly does not cache MRU buffers."
97