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selftests/mm: check after-split folio orders in split_huge_page_test 

Instead of just checking the existence of PMD folios before and after folio
split tests, use check_folio_orders() to check after-split folio orders.

The split ranges in split_thp_in_pagecache_to_order_at() are changed to
[addr, addr + pagesize) for every pmd_pagesize. It prevents folios within
the range being split multiple times due to debugfs split function always
perform splits with a pagesize step for a given range.

The following tests are not changed:
1. split_pte_mapped_thp: the test already uses kpageflags to check;
2. split_file_backed_thp: no vaddr available.

Link: https://lkml.kernel.org/r/20250818184622.1521620-6-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Mariano Pache <npache@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: wang lian <lianux.mm@gmail.com>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
pull/1354/merge
Zi Yan 2025-08-18 14:46:22 -04:00 committed by Andrew Morton
parent fca418e59a
commit c55ed758e0
1 changed files with 64 additions and 24 deletions
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88
tools/testing/selftests/mm/split_huge_page_test.c
View File

@ -26,6 +26,7 @@ uint64_t pagesize;
unsigned int pageshift;
uint64_t pmd_pagesize;
unsigned int pmd_order;
int *expected_orders;
#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages"
#define SMAP_PATH "/proc/self/smaps"
@ -35,6 +36,11 @@ unsigned int pmd_order;
#define PID_FMT_OFFSET "%d,0x%lx,0x%lx,%d,%d"
#define PATH_FMT "%s,0x%lx,0x%lx,%d"
const char *pagemap_proc = "/proc/self/pagemap";
const char *kpageflags_proc = "/proc/kpageflags";
int pagemap_fd;
int kpageflags_fd;
static bool is_backed_by_folio(char *vaddr, int order, int pagemap_fd,
int kpageflags_fd)
{
@ -367,6 +373,13 @@ static void split_pmd_thp_to_order(int order)
if (one_page[i] != (char)i)
ksft_exit_fail_msg("%ld byte corrupted\n", i);
memset(expected_orders, 0, sizeof(int) * (pmd_order + 1));
expected_orders[order] = 4 << (pmd_order - order);
if (check_after_split_folio_orders(one_page, len, pagemap_fd,
kpageflags_fd, expected_orders,
(pmd_order + 1)))
ksft_exit_fail_msg("Unexpected THP split\n");
if (!check_huge_anon(one_page, 0, pmd_pagesize))
ksft_exit_fail_msg("Still AnonHugePages not split\n");
@ -381,22 +394,6 @@ static void split_pte_mapped_thp(void)
size_t len = 4 * pmd_pagesize;
uint64_t thp_size;
size_t i;
const char *pagemap_template = "/proc/%d/pagemap";
const char *kpageflags_proc = "/proc/kpageflags";
char pagemap_proc[255];
int pagemap_fd;
int kpageflags_fd;
if (snprintf(pagemap_proc, 255, pagemap_template, getpid()) < 0)
ksft_exit_fail_msg("get pagemap proc error: %s\n", strerror(errno));
pagemap_fd = open(pagemap_proc, O_RDONLY);
if (pagemap_fd == -1)
ksft_exit_fail_msg("read pagemap: %s\n", strerror(errno));
kpageflags_fd = open(kpageflags_proc, O_RDONLY);
if (kpageflags_fd == -1)
ksft_exit_fail_msg("read kpageflags: %s\n", strerror(errno));
one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
@ -454,8 +451,6 @@ static void split_pte_mapped_thp(void)
ksft_test_result_pass("Split PTE-mapped huge pages successful\n");
munmap(one_page, len);
close(pagemap_fd);
close(kpageflags_fd);
}
static void split_file_backed_thp(int order)
@ -660,6 +655,7 @@ static void split_thp_in_pagecache_to_order_at(size_t fd_size,
const char *fs_loc, int order, int offset)
{
int fd;
char *split_addr;
char *addr;
size_t i;
char testfile[INPUT_MAX];
@ -673,14 +669,33 @@ static void split_thp_in_pagecache_to_order_at(size_t fd_size,
err = create_pagecache_thp_and_fd(testfile, fd_size, &fd, &addr);
if (err)
return;
err = 0;
if (offset == -1)
write_debugfs(PID_FMT, getpid(), (uint64_t)addr,
(uint64_t)addr + fd_size, order);
else
write_debugfs(PID_FMT_OFFSET, getpid(), (uint64_t)addr,
(uint64_t)addr + fd_size, order, offset);
memset(expected_orders, 0, sizeof(int) * (pmd_order + 1));
/*
* use [split_addr, split_addr + pagesize) range to split THPs, since
* the debugfs function always split a range with pagesize step and
* providing a full [addr, addr + fd_size) range can trigger multiple
* splits, complicating after-split result checking.
*/
if (offset == -1) {
for (split_addr = addr; split_addr < addr + fd_size; split_addr += pmd_pagesize)
write_debugfs(PID_FMT, getpid(), (uint64_t)split_addr,
(uint64_t)split_addr + pagesize, order);
expected_orders[order] = fd_size / (pagesize << order);
} else {
int times = fd_size / pmd_pagesize;
for (split_addr = addr; split_addr < addr + fd_size; split_addr += pmd_pagesize)
write_debugfs(PID_FMT_OFFSET, getpid(), (uint64_t)split_addr,
(uint64_t)split_addr + pagesize, order, offset);
for (i = order + 1; i < pmd_order; i++)
expected_orders[i] = times;
expected_orders[order] = 2 * times;
}
for (i = 0; i < fd_size; i++)
if (*(addr + i) != (char)i) {
@ -689,6 +704,14 @@ static void split_thp_in_pagecache_to_order_at(size_t fd_size,
goto out;
}
if (check_after_split_folio_orders(addr, fd_size, pagemap_fd,
kpageflags_fd, expected_orders,
(pmd_order + 1))) {
ksft_print_msg("Unexpected THP split\n");
err = 1;
goto out;
}
if (!check_huge_file(addr, 0, pmd_pagesize)) {
ksft_print_msg("Still FilePmdMapped not split\n");
err = EXIT_FAILURE;
@ -740,9 +763,22 @@ int main(int argc, char **argv)
nr_pages = pmd_pagesize / pagesize;
pmd_order = sz2ord(pmd_pagesize, pagesize);
expected_orders = (int *)malloc(sizeof(int) * (pmd_order + 1));
if (!expected_orders)
ksft_exit_fail_msg("Fail to allocate memory: %s\n", strerror(errno));
tests = 2 + (pmd_order - 1) + (2 * pmd_order) + (pmd_order - 1) * 4 + 2;
ksft_set_plan(tests);
pagemap_fd = open(pagemap_proc, O_RDONLY);
if (pagemap_fd == -1)
ksft_exit_fail_msg("read pagemap: %s\n", strerror(errno));
kpageflags_fd = open(kpageflags_proc, O_RDONLY);
if (kpageflags_fd == -1)
ksft_exit_fail_msg("read kpageflags: %s\n", strerror(errno));
fd_size = 2 * pmd_pagesize;
split_pmd_zero_pages();
@ -767,6 +803,10 @@ int main(int argc, char **argv)
split_thp_in_pagecache_to_order_at(fd_size, fs_loc, i, offset);
cleanup_thp_fs(fs_loc, created_tmp);
close(pagemap_fd);
close(kpageflags_fd);
free(expected_orders);
ksft_finished();
return 0;