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| author | Ming Lei <ming.lei@redhat.com> | 2026-03-31 18:31:58 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2026-04-07 16:42:23 +0300 |
| commit | 2f1e9468bdcba7e7572e16defd3c516f24281f14 (patch) | |
| tree | f78c23955a35c32e4d46da19529d19b6a235472f /tools/testing | |
| parent | ec20aa44ac2629943c9b2b5524bcb55d778f746c (diff) | |
| download | linux-2f1e9468bdcba7e7572e16defd3c516f24281f14.tar.xz | |
selftests/ublk: add shared memory zero-copy test
Add test_shmem_zc_01.sh which tests UBLK_IO_F_SHMEM_ZC on the null
target using a hugetlbfs shared buffer. Both kublk (--htlb) and fio
(--mem=mmaphuge:<path>) mmap the same hugetlbfs file with MAP_SHARED,
sharing physical pages. The kernel PFN match enables zero-copy I/O.
Uses standard fio --mem=mmaphuge:<path> (supported since fio 1.10),
no patched fio required.
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Link: https://patch.msgid.link/20260331153207.3635125-8-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'tools/testing')
| -rw-r--r-- | tools/testing/selftests/ublk/Makefile | 2 | ||||
| -rwxr-xr-x | tools/testing/selftests/ublk/test_shmemzc_01.sh | 72 |
2 files changed, 74 insertions, 0 deletions
diff --git a/tools/testing/selftests/ublk/Makefile b/tools/testing/selftests/ublk/Makefile index d338668c5a5f..bf5e9fcf36b8 100644 --- a/tools/testing/selftests/ublk/Makefile +++ b/tools/testing/selftests/ublk/Makefile @@ -52,6 +52,8 @@ TEST_PROGS += test_stripe_06.sh TEST_PROGS += test_part_01.sh TEST_PROGS += test_part_02.sh +TEST_PROGS += test_shmemzc_01.sh + TEST_PROGS += test_stress_01.sh TEST_PROGS += test_stress_02.sh TEST_PROGS += test_stress_03.sh diff --git a/tools/testing/selftests/ublk/test_shmemzc_01.sh b/tools/testing/selftests/ublk/test_shmemzc_01.sh new file mode 100755 index 000000000000..47210af2aa20 --- /dev/null +++ b/tools/testing/selftests/ublk/test_shmemzc_01.sh @@ -0,0 +1,72 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0 +# Test: shmem_zc with hugetlbfs buffer on null target +# +# kublk and fio both mmap the same hugetlbfs file (MAP_SHARED), +# so they share physical pages. The kernel PFN match enables +# zero-copy I/O without socket-based fd passing. + +. "$(cd "$(dirname "$0")" && pwd)"/test_common.sh + +ERR_CODE=0 + +_prep_test "shmem_zc" "null target hugetlbfs shmem zero-copy test" + +if ! _have_program fio; then + echo "SKIP: fio not available" + exit "$UBLK_SKIP_CODE" +fi + +if ! grep -q hugetlbfs /proc/filesystems; then + echo "SKIP: hugetlbfs not supported" + exit "$UBLK_SKIP_CODE" +fi + +# Allocate hugepages +OLD_NR_HP=$(cat /proc/sys/vm/nr_hugepages) +echo 10 > /proc/sys/vm/nr_hugepages +NR_HP=$(cat /proc/sys/vm/nr_hugepages) +if [ "$NR_HP" -lt 2 ]; then + echo "SKIP: cannot allocate hugepages" + echo "$OLD_NR_HP" > /proc/sys/vm/nr_hugepages + exit "$UBLK_SKIP_CODE" +fi + +# Mount hugetlbfs +HTLB_MNT=$(mktemp -d "${UBLK_TEST_DIR}/htlb_mnt_XXXXXX") +if ! mount -t hugetlbfs none "$HTLB_MNT"; then + echo "SKIP: cannot mount hugetlbfs" + rmdir "$HTLB_MNT" + echo "$OLD_NR_HP" > /proc/sys/vm/nr_hugepages + exit "$UBLK_SKIP_CODE" +fi + +HTLB_FILE="$HTLB_MNT/ublk_buf" +fallocate -l 4M "$HTLB_FILE" + +dev_id=$(_add_ublk_dev -t null --shmem_zc --htlb "$HTLB_FILE") +_check_add_dev $TID $? + +fio --name=htlb_zc \ + --filename=/dev/ublkb"${dev_id}" \ + --ioengine=io_uring \ + --rw=randwrite \ + --direct=1 \ + --bs=4k \ + --size=4M \ + --iodepth=32 \ + --mem=mmaphuge:"$HTLB_FILE" \ + > /dev/null 2>&1 +ERR_CODE=$? + +# Delete device first so daemon releases the htlb mmap +_ublk_del_dev "${dev_id}" + +rm -f "$HTLB_FILE" +umount "$HTLB_MNT" +rmdir "$HTLB_MNT" +echo "$OLD_NR_HP" > /proc/sys/vm/nr_hugepages + +_cleanup_test "shmem_zc" + +_show_result $TID $ERR_CODE |