Add a kselftest for the dax/kmem whole-device "hotplug" sysfs attribute (/sys/bus/dax/devices/daxX.Y/hotplug), which transitions a kmem-backed dax device between "unplugged", "online" and "online_movable". Provisioning a devdax device and binding it to kmem needs daxctl/ndctl (or the tools/testing/nvdimm emulation) and is out of scope for an in-tree selftest, so the test discovers an already kmem-bound dax device and SKIPs (KSFT_SKIP) when none is present or when the memory cannot be freed to reach a known baseline. When a device is available it validates the interface contract: - online / online_movable actually add memory (MemTotal grows), - online is idempotent, - switching between online types without an intervening unplug is rejected, - unplug removes the memory and the reported state matches reality, - invalid input is rejected. In particular it covers the online -> unplug -> online_movable -> unplug cycle: a re-online must re-reserve the per-range resources so that a subsequent unplug actually offlines and removes the memory instead of silently reporting success while the memory stays online. Signed-off-by: Gregory Price --- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/dax/Makefile | 6 + tools/testing/selftests/dax/config | 4 + .../testing/selftests/dax/dax-kmem-hotplug.sh | 145 ++++++++++++++++++ tools/testing/selftests/dax/settings | 1 + 5 files changed, 157 insertions(+) create mode 100644 tools/testing/selftests/dax/Makefile create mode 100644 tools/testing/selftests/dax/config create mode 100755 tools/testing/selftests/dax/dax-kmem-hotplug.sh create mode 100644 tools/testing/selftests/dax/settings diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile index 6e59b8f63e41..8c2b4f97619c 100644 --- a/tools/testing/selftests/Makefile +++ b/tools/testing/selftests/Makefile @@ -14,6 +14,7 @@ TARGETS += core TARGETS += cpufreq TARGETS += cpu-hotplug TARGETS += damon +TARGETS += dax TARGETS += devices/error_logs TARGETS += devices/probe TARGETS += dmabuf-heaps diff --git a/tools/testing/selftests/dax/Makefile b/tools/testing/selftests/dax/Makefile new file mode 100644 index 000000000000..25a4f3d73a5b --- /dev/null +++ b/tools/testing/selftests/dax/Makefile @@ -0,0 +1,6 @@ +# SPDX-License-Identifier: GPL-2.0 +all: + +TEST_PROGS := dax-kmem-hotplug.sh + +include ../lib.mk diff --git a/tools/testing/selftests/dax/config b/tools/testing/selftests/dax/config new file mode 100644 index 000000000000..4c9aaeb6ceb4 --- /dev/null +++ b/tools/testing/selftests/dax/config @@ -0,0 +1,4 @@ +CONFIG_DEV_DAX=m +CONFIG_DEV_DAX_KMEM=m +CONFIG_MEMORY_HOTPLUG=y +CONFIG_MEMORY_HOTREMOVE=y diff --git a/tools/testing/selftests/dax/dax-kmem-hotplug.sh b/tools/testing/selftests/dax/dax-kmem-hotplug.sh new file mode 100755 index 000000000000..705a34cc3c6d --- /dev/null +++ b/tools/testing/selftests/dax/dax-kmem-hotplug.sh @@ -0,0 +1,145 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# +# Exercise the dax/kmem whole-device "hotplug" sysfs attribute: +# /sys/bus/dax/devices/daxX.Y/hotplug -> unplugged | online | online_movable +# +# The test needs a dax device already bound to the kmem driver (so the +# 'hotplug' attribute exists). Provisioning a devdax device and binding it to +# kmem requires daxctl/ndctl (or the tools/testing/nvdimm emulation) and is out +# of scope here; if no suitable device is found the test SKIPs. +# +# To actually run it, provision a kmem-backed dax device first. For example, +# carve a chunk of RAM into an emulated pmem region via the kernel command line +# (the region must be at least one memory block, e.g. 128MiB on x86): +# +# memmap=2G!4G +# +# then, in the booted system: +# +# ndctl create-namespace -m devdax -e namespace0.0 -f +# daxctl reconfigure-device -N -m system-ram dax0.0 # binds the kmem driver +# ./dax-kmem-hotplug.sh + +DIR="$(dirname "$(readlink -f "$0")")" +. "$DIR"/../kselftest/ktap_helpers.sh + +DAX_BASE=/sys/bus/dax/devices + +memtotal_kb() { awk '/^MemTotal:/ {print $2}' /proc/meminfo; } +get_state() { cat "$HP" 2>/dev/null; } +# set_state STATE -- write a state to the hotplug attribute; returns the +# write's exit status (0 = accepted by the kernel) +set_state() { echo "$1" > "$HP" 2>/dev/null; } + +find_kmem_dax() { + local d drv + for d in "$DAX_BASE"/dax*; do + [ -e "$d/hotplug" ] || continue + drv=$(readlink "$d/driver" 2>/dev/null) + [ "$(basename "${drv:-}")" = kmem ] || continue + basename "$d" + return 0 + done + return 1 +} + +ktap_print_header + +if [ "$UID" != 0 ]; then + ktap_skip_all "must be run as root" + exit "$KSFT_SKIP" +fi + +DAX=$(find_kmem_dax) +if [ -z "$DAX" ]; then + ktap_skip_all "no kmem-bound dax device with a hotplug attribute" + exit "$KSFT_SKIP" +fi +HP=$DAX_BASE/$DAX/hotplug +ORIG=$(get_state) + +# A failure to reach the baseline is environmental (memory in use), not an +# interface failure, so skip rather than fail. +set_state unplugged; rc=$? +if [ "$rc" != 0 ] || [ "$(get_state)" != unplugged ]; then + ktap_skip_all "$DAX: cannot reach 'unplugged' baseline (memory in use?)" + [ -n "$ORIG" ] && set_state "$ORIG" + exit "$KSFT_SKIP" +fi +mt_unplugged=$(memtotal_kb) + +ktap_print_msg "using $DAX (initial state was: $ORIG)" +ktap_set_plan 8 + +set_state online; rc=$? +mt_online=$(memtotal_kb) +if [ "$rc" = 0 ] && [ "$(get_state)" = online ] && [ "$mt_online" -gt "$mt_unplugged" ]; then + ktap_test_pass "online: state=online, MemTotal $mt_unplugged -> $mt_online kB" +else + ktap_test_fail "online: rc=$rc state=$(get_state) MemTotal $mt_unplugged -> $mt_online" +fi + +set_state online; rc=$? +if [ "$rc" = 0 ] && [ "$(get_state)" = online ]; then + ktap_test_pass "online idempotent" +else + ktap_test_fail "online idempotent: rc=$rc state=$(get_state)" +fi + +set_state online_movable; rc=$? +if [ "$rc" != 0 ] && [ "$(get_state)" = online ]; then + ktap_test_pass "reject online_movable without intervening unplug" +else + ktap_test_fail "online->online_movable not rejected: rc=$rc state=$(get_state)" +fi + +set_state unplugged; rc=$? +mt=$(memtotal_kb) +if [ "$rc" = 0 ] && [ "$(get_state)" = unplugged ] && [ "$mt" -lt "$mt_online" ]; then + ktap_test_pass "unplug from online: MemTotal $mt_online -> $mt kB" +else + ktap_test_fail "unplug from online: rc=$rc state=$(get_state) MemTotal $mt_online -> $mt" +fi + +set_state online_movable; rc=$? +mt_mov=$(memtotal_kb) +if [ "$rc" = 0 ] && [ "$(get_state)" = online_movable ] && [ "$mt_mov" -gt "$mt_unplugged" ]; then + ktap_test_pass "online_movable after unplug: MemTotal $mt_unplugged -> $mt_mov kB" +else + ktap_test_fail "online_movable after unplug: rc=$rc state=$(get_state) MemTotal=$mt_mov" +fi + +# The online -> unplug -> online_movable -> unplug cycle once regressed: a +# re-online failed to re-reserve the per-range resources, so this final unplug +# reported success while leaving the memory online. Assert it is really freed. +set_state unplugged; rc=$? +mt=$(memtotal_kb) +if [ "$rc" != 0 ]; then + ktap_test_skip "unplug from movable not accepted (memory in use?) rc=$rc" +elif [ "$(get_state)" = unplugged ] && [ "$mt" -lt "$mt_mov" ]; then + ktap_test_pass "unplug from online_movable removed memory: $mt_mov -> $mt kB" +else + ktap_test_fail "unplug success but memory remained: $(get_state) $mt_mov -> $mt kB" +fi + +set_state online_kernel; rc=$? +mt=$(memtotal_kb) +if [ "$rc" = 0 ] && [ "$(get_state)" = online_kernel ] && [ "$mt" -gt "$mt_unplugged" ]; then + ktap_test_pass "online_kernel: MemTotal $mt_unplugged -> $mt kB" +else + ktap_test_fail "online_kernel: rc=$rc state=$(get_state) MemTotal=$mt" +fi +set_state unplugged + +before=$(get_state) +set_state bogus_state; rc=$? +if [ "$rc" != 0 ] && [ "$(get_state)" = "$before" ]; then + ktap_test_pass "reject invalid state string" +else + ktap_test_fail "invalid state not rejected: rc=$rc state=$(get_state)" +fi + +[ -n "$ORIG" ] && set_state "$ORIG" + +ktap_finished diff --git a/tools/testing/selftests/dax/settings b/tools/testing/selftests/dax/settings new file mode 100644 index 000000000000..ba4d85f74cd6 --- /dev/null +++ b/tools/testing/selftests/dax/settings @@ -0,0 +1 @@ +timeout=90 -- 2.54.0