On LoongArch 3C5000 Dual-Way machine, there are 32 CPUs and 128G RAM,
there are some errors with run vmalloc test with command like this
insmod test_vmalloc.ko nr_threads=32 run_test_mask=0x3af
Here is part of error message and summary test report for failed cases:
WARNING: CPU: 13 PID: 1457 at mm/vmalloc.c:503 vmap_small_pages_range_noflush+0x388/0x510
CPU: 13 UID: 0 PID: 1457 Comm: vmalloc_test/15 Not tainted 6.12.0-rc2+ #93
Trying to vfree() nonexistent vm area (000000004dec9ced)
WARNING: CPU: 3 PID: 1444 at mm/vmalloc.c:3345 vfree+0x1e8/0x4c8
CPU: 3 UID: 0 PID: 1444 Comm: vmalloc_test/2
Trying to vfree() bad address (00000000fc7c9da5)
WARNING: CPU: 10 PID: 1552 at mm/vmalloc.c:3210 remove_vm_area+0x88/0x98
CPU: 10 UID: 0 PID: 1552 Comm: kworker/u144:3
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_align_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: kvfree_rcu_2_arg_vmalloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_align_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: fix_size_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_align_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_align_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: kvfree_rcu_2_arg_vmalloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: random_size_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: kvfree_rcu_1_arg_vmalloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: fix_size_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
Summary: long_busy_list_alloc_test passed: 0 failed: 1 repeat: 1 loops: 1000000
The mainly problem is that function set_pte() and pte_free() is not atomic,
since these functions need modify two consecutive pte entries for kernel
space area to assure that both pte entries with PAGE_GLOBAL bit set. And
there is contension problem between them.
With this patchset, vmalloc test case passes to run with command
insmod test_vmalloc.ko nr_threads=32 run_test_mask=0x3af
---
v1 ... v2:
1. Solve compile warning issue by declaring function
kernel_pte_init() in header file include/linux/mm.h
2. Add kernel_pte_init() in function zero_pmd_populate() called by
file mm/kasan/init.c
3. Merge the first two patches into one since both these two patches
set pte entry with PAGE_GLOBAL in different modules
4. Remove amotic operation with pte_clear(), using generic read and
clear operation, vmalloc test pass to run also
5. refresh some comments description
---
Bibo Mao (3):
LoongArch: Set initial pte entry with PAGE_GLOBAL for kernel space
LoongArch: Add barrier between set_pte and memory access
LoongArch: Remove pte buddy set with set_pte and pte_clear function
arch/loongarch/include/asm/cacheflush.h | 14 +++++++++-
arch/loongarch/include/asm/pgalloc.h | 13 +++++++++
arch/loongarch/include/asm/pgtable.h | 36 +++++--------------------
arch/loongarch/mm/init.c | 4 ++-
arch/loongarch/mm/kasan_init.c | 4 ++-
arch/loongarch/mm/pgtable.c | 22 +++++++++++++++
include/linux/mm.h | 1 +
mm/kasan/init.c | 8 +++++-
mm/sparse-vmemmap.c | 5 ++++
9 files changed, 73 insertions(+), 34 deletions(-)
base-commit: 6485cf5ea253d40d507cd71253c9568c5470cd27
--
2.39.3
