forked from Minki/linux
a7504ed14f
Patch series "migrate_pages(): fix several bugs in error path", v3.
During review the code of migrate_pages() and build a test program for
it. Several bugs in error path are identified and fixed in this
series.
Most patches are tested via
- Apply error-inject.patch in Linux kernel
- Compile test-migrate.c (with -lnuma)
- Test with test-migrate.sh
error-inject.patch, test-migrate.c, and test-migrate.sh are as below.
It turns out that error injection is an important tool to fix bugs in
error path.
This patch (of 8):
The return value of move_pages() syscall is incorrect when counting
the remaining pages to be migrated. For example, for the following
test program,
"
#define _GNU_SOURCE
#include <stdbool.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/uio.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <unistd.h>
#include <numaif.h>
#include <numa.h>
#ifndef MADV_FREE
#define MADV_FREE 8 /* free pages only if memory pressure */
#endif
#define ONE_MB (1024 * 1024)
#define MAP_SIZE (16 * ONE_MB)
#define THP_SIZE (2 * ONE_MB)
#define THP_MASK (THP_SIZE - 1)
#define ERR_EXIT_ON(cond, msg) \
do { \
int __cond_in_macro = (cond); \
if (__cond_in_macro) \
error_exit(__cond_in_macro, (msg)); \
} while (0)
void error_msg(int ret, int nr, int *status, const char *msg)
{
int i;
fprintf(stderr, "Error: %s, ret : %d, error: %s\n",
msg, ret, strerror(errno));
if (!nr)
return;
fprintf(stderr, "status: ");
for (i = 0; i < nr; i++)
fprintf(stderr, "%d ", status[i]);
fprintf(stderr, "\n");
}
void error_exit(int ret, const char *msg)
{
error_msg(ret, 0, NULL, msg);
exit(1);
}
int page_size;
bool do_vmsplice;
bool do_thp;
static int pipe_fds[2];
void *addr;
char *pn;
char *pn1;
void *pages[2];
int status[2];
void prepare()
{
int ret;
struct iovec iov;
if (addr) {
munmap(addr, MAP_SIZE);
close(pipe_fds[0]);
close(pipe_fds[1]);
}
ret = pipe(pipe_fds);
ERR_EXIT_ON(ret, "pipe");
addr = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
ERR_EXIT_ON(addr == MAP_FAILED, "mmap");
if (do_thp) {
ret = madvise(addr, MAP_SIZE, MADV_HUGEPAGE);
ERR_EXIT_ON(ret, "advise hugepage");
}
pn = (char *)(((unsigned long)addr + THP_SIZE) & ~THP_MASK);
pn1 = pn + THP_SIZE;
pages[0] = pn;
pages[1] = pn1;
*pn = 1;
if (do_vmsplice) {
iov.iov_base = pn;
iov.iov_len = page_size;
ret = vmsplice(pipe_fds[1], &iov, 1, 0);
ERR_EXIT_ON(ret < 0, "vmsplice");
}
status[0] = status[1] = 1024;
}
void test_migrate()
{
int ret;
int nodes[2] = { 1, 1 };
pid_t pid = getpid();
prepare();
ret = move_pages(pid, 1, pages, nodes, status, MPOL_MF_MOVE_ALL);
error_msg(ret, 1, status, "move 1 page");
prepare();
ret = move_pages(pid, 2, pages, nodes, status, MPOL_MF_MOVE_ALL);
error_msg(ret, 2, status, "move 2 pages, page 1 not mapped");
prepare();
*pn1 = 1;
ret = move_pages(pid, 2, pages, nodes, status, MPOL_MF_MOVE_ALL);
error_msg(ret, 2, status, "move 2 pages");
prepare();
*pn1 = 1;
nodes[1] = 0;
ret = move_pages(pid, 2, pages, nodes, status, MPOL_MF_MOVE_ALL);
error_msg(ret, 2, status, "move 2 pages, page 1 to node 0");
}
int main(int argc, char *argv[])
{
numa_run_on_node(0);
page_size = getpagesize();
test_migrate();
fprintf(stderr, "\nMake page 0 cannot be migrated:\n");
do_vmsplice = true;
test_migrate();
fprintf(stderr, "\nTest THP:\n");
do_thp = true;
do_vmsplice = false;
test_migrate();
fprintf(stderr, "\nTHP: make page 0 cannot be migrated:\n");
do_vmsplice = true;
test_migrate();
return 0;
}
"
The output of the current kernel is,
"
Error: move 1 page, ret : 0, error: Success
status: 1
Error: move 2 pages, page 1 not mapped, ret : 0, error: Success
status: 1 -14
Error: move 2 pages, ret : 0, error: Success
status: 1 1
Error: move 2 pages, page 1 to node 0, ret : 0, error: Success
status: 1 0
Make page 0 cannot be migrated:
Error: move 1 page, ret : 0, error: Success
status: 1024
Error: move 2 pages, page 1 not mapped, ret : 1, error: Success
status: 1024 -14
Error: move 2 pages, ret : 0, error: Success
status: 1024 1024
Error: move 2 pages, page 1 to node 0, ret : 1, error: Success
status: 1024 1024
"
While the expected output is,
"
Error: move 1 page, ret : 0, error: Success
status: 1
Error: move 2 pages, page 1 not mapped, ret : 0, error: Success
status: 1 -14
Error: move 2 pages, ret : 0, error: Success
status: 1 1
Error: move 2 pages, page 1 to node 0, ret : 0, error: Success
status: 1 0
Make page 0 cannot be migrated:
Error: move 1 page, ret : 1, error: Success
status: 1024
Error: move 2 pages, page 1 not mapped, ret : 1, error: Success
status: 1024 -14
Error: move 2 pages, ret : 1, error: Success
status: 1024 1024
Error: move 2 pages, page 1 to node 0, ret : 2, error: Success
status: 1024 1024
"
Fix this via correcting the remaining pages counting. With the fix,
the output for the test program as above is expected.
Link: https://lkml.kernel.org/r/20220817081408.513338-1-ying.huang@intel.com
Link: https://lkml.kernel.org/r/20220817081408.513338-2-ying.huang@intel.com
Fixes:
|
||
|---|---|---|
| .. | ||
| damon | ||
| kasan | ||
| kfence | ||
| backing-dev.c | ||
| balloon_compaction.c | ||
| bootmem_info.c | ||
| cma_debug.c | ||
| cma_sysfs.c | ||
| cma.c | ||
| cma.h | ||
| compaction.c | ||
| debug_page_ref.c | ||
| debug_vm_pgtable.c | ||
| debug.c | ||
| dmapool.c | ||
| early_ioremap.c | ||
| fadvise.c | ||
| failslab.c | ||
| filemap.c | ||
| folio-compat.c | ||
| frontswap.c | ||
| gup_test.c | ||
| gup_test.h | ||
| gup.c | ||
| highmem.c | ||
| hmm.c | ||
| huge_memory.c | ||
| hugetlb_cgroup.c | ||
| hugetlb_vmemmap.c | ||
| hugetlb_vmemmap.h | ||
| hugetlb.c | ||
| hwpoison-inject.c | ||
| init-mm.c | ||
| internal.h | ||
| interval_tree.c | ||
| io-mapping.c | ||
| ioremap.c | ||
| Kconfig | ||
| Kconfig.debug | ||
| khugepaged.c | ||
| kmemleak.c | ||
| ksm.c | ||
| list_lru.c | ||
| maccess.c | ||
| madvise.c | ||
| Makefile | ||
| mapping_dirty_helpers.c | ||
| memblock.c | ||
| memcontrol.c | ||
| memfd.c | ||
| memory_hotplug.c | ||
| memory-failure.c | ||
| memory.c | ||
| mempolicy.c | ||
| mempool.c | ||
| memremap.c | ||
| memtest.c | ||
| migrate_device.c | ||
| migrate.c | ||
| mincore.c | ||
| mlock.c | ||
| mm_init.c | ||
| mmap_lock.c | ||
| mmap.c | ||
| mmu_gather.c | ||
| mmu_notifier.c | ||
| mmzone.c | ||
| mprotect.c | ||
| mremap.c | ||
| msync.c | ||
| nommu.c | ||
| oom_kill.c | ||
| page_alloc.c | ||
| page_counter.c | ||
| page_ext.c | ||
| page_idle.c | ||
| page_io.c | ||
| page_isolation.c | ||
| page_owner.c | ||
| page_poison.c | ||
| page_reporting.c | ||
| page_reporting.h | ||
| page_table_check.c | ||
| page_vma_mapped.c | ||
| page-writeback.c | ||
| pagewalk.c | ||
| percpu-internal.h | ||
| percpu-km.c | ||
| percpu-stats.c | ||
| percpu-vm.c | ||
| percpu.c | ||
| pgalloc-track.h | ||
| pgtable-generic.c | ||
| process_vm_access.c | ||
| ptdump.c | ||
| readahead.c | ||
| rmap.c | ||
| rodata_test.c | ||
| secretmem.c | ||
| shmem.c | ||
| shrinker_debug.c | ||
| shuffle.c | ||
| shuffle.h | ||
| slab_common.c | ||
| slab.c | ||
| slab.h | ||
| slob.c | ||
| slub.c | ||
| sparse-vmemmap.c | ||
| sparse.c | ||
| swap_cgroup.c | ||
| swap_slots.c | ||
| swap_state.c | ||
| swap.c | ||
| swap.h | ||
| swapfile.c | ||
| truncate.c | ||
| usercopy.c | ||
| userfaultfd.c | ||
| util.c | ||
| vmacache.c | ||
| vmalloc.c | ||
| vmpressure.c | ||
| vmscan.c | ||
| vmstat.c | ||
| workingset.c | ||
| z3fold.c | ||
| zbud.c | ||
| zpool.c | ||
| zsmalloc.c | ||
| zswap.c | ||