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selftests/mm: add writable-file collapse tests for khugepaged

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collapse_file() now supports collapsing clean pagecache folios from
writable files, so add corresponding tests.

Note that madvise(MADV_COLLAPSE) works for dirty pagecache folios from
writable files, because collapse_single_pmd() triggers a synchronous
writeback when first attempt of collapse_file() fails.  That writeback
makes dirty folios clean and the retry of collapse_file() succeeds.

Link: https://lore.kernel.org/20260517135416.1434539-15-ziy@nvidia.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Chris Mason <clm@fb.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Liam Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Zi Yan 2026-05-17 09:54:16 -04:00 committed by Andrew Morton
parent 1b6444331b
commit 366aaad862
1 changed files with 85 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

111
tools/testing/selftests/mm/khugepaged.c
View File

@ -41,6 +41,12 @@ enum vma_type {
VMA_SHMEM,
};
enum file_setup_ops {
FILE_SETUP_READ_ONLY_FS,
FILE_SETUP_READ_WRITE_FS_READ_DATA,
FILE_SETUP_READ_WRITE_FS_WRITE_DATA,
};
struct mem_ops {
void *(*setup_area)(int nr_hpages);
void (*cleanup_area)(void *p, unsigned long size);
@ -50,7 +56,8 @@ struct mem_ops {
};
static struct mem_ops *read_only_file_ops;
static struct mem_ops *read_write_file_ops;
static struct mem_ops *read_write_file_read_ops;
static struct mem_ops *read_write_file_write_ops;
static struct mem_ops *anon_ops;
static struct mem_ops *shmem_ops;
@ -113,7 +120,8 @@ static void restore_settings(int sig)
static void save_settings(void)
{
printf("Save THP and khugepaged settings...");
if ((read_only_file_ops || read_write_file_ops) &&
if ((read_only_file_ops || read_write_file_read_ops ||
read_write_file_write_ops) &&
finfo.type == VMA_FILE)
thp_set_read_ahead_path(finfo.dev_queue_read_ahead_path);
thp_save_settings();
@ -366,10 +374,10 @@ static bool anon_check_huge(void *addr, int nr_hpages)
return check_huge_anon(addr, nr_hpages, hpage_pmd_size);
}
static void *file_setup_area_common(int nr_hpages, bool read_only)
static void *file_setup_area_common(int nr_hpages, enum file_setup_ops setup)
{
const int open_opt = read_only ? O_RDONLY : O_RDWR;
const int mmap_prot = read_only ? PROT_READ : (PROT_READ | PROT_WRITE);
const int open_opt = setup == FILE_SETUP_READ_ONLY_FS ? O_RDONLY : O_RDWR;
const int mmap_prot = setup == FILE_SETUP_READ_ONLY_FS ? PROT_READ : (PROT_READ | PROT_WRITE);
int fd;
void *p;
unsigned long size;
@ -405,7 +413,10 @@ static void *file_setup_area_common(int nr_hpages, bool read_only)
success("OK");
printf("Opening %s %s for collapse...", finfo.path,
read_only ? "read-only" : "read-write");
setup == FILE_SETUP_READ_ONLY_FS ? "read-only" :
setup == FILE_SETUP_READ_WRITE_FS_READ_DATA ?
"read-write (read)" :
"read-write (write)");
finfo.fd = open(finfo.path, open_opt, 777);
if (finfo.fd < 0) {
perror("open()");
@ -425,12 +436,17 @@ static void *file_setup_area_common(int nr_hpages, bool read_only)
static void *file_setup_read_only_area(int nr_hpages)
{
return file_setup_area_common(nr_hpages, /* read_only= */ true);
return file_setup_area_common(nr_hpages, FILE_SETUP_READ_ONLY_FS);
}
static void *file_setup_read_write_area(int nr_hpages)
static void *file_setup_read_write_fs_read_area(int nr_hpages)
{
return file_setup_area_common(nr_hpages, /* read_only= */ false);
return file_setup_area_common(nr_hpages, FILE_SETUP_READ_WRITE_FS_READ_DATA);
}
static void *file_setup_read_write_fs_write_area(int nr_hpages)
{
return file_setup_area_common(nr_hpages, FILE_SETUP_READ_WRITE_FS_WRITE_DATA);
}
static void file_cleanup_area(void *p, unsigned long size)
@ -448,6 +464,16 @@ static void file_fault_read(void *p, unsigned long start, unsigned long end)
}
}
static void file_fault_read_and_flush(void *p, unsigned long start, unsigned long end)
{
file_fault_read(p, start, end);
/*
* make folio clean, since dirty folios from read&write file are
* rejected and not flushed
*/
msync((char *)p + start, end - start, MS_SYNC);
}
static void file_fault_write(void *p, unsigned long start, unsigned long end)
{
if (madvise(((char *)p) + start, end - start, MADV_POPULATE_WRITE)) {
@ -519,8 +545,16 @@ static struct mem_ops __read_only_file_ops = {
.name = "file",
};
static struct mem_ops __read_write_file_ops = {
.setup_area = &file_setup_read_write_area,
static struct mem_ops __read_write_file_read_ops = {
.setup_area = &file_setup_read_write_fs_read_area,
.cleanup_area = &file_cleanup_area,
.fault = &file_fault_read_and_flush,
.check_huge = &file_check_huge,
.name = "file",
};
static struct mem_ops __read_write_file_write_ops = {
.setup_area = &file_setup_read_write_fs_write_area,
.cleanup_area = &file_cleanup_area,
.fault = &file_fault_write,
.check_huge = &file_check_huge,
@ -537,7 +571,9 @@ static struct mem_ops __shmem_ops = {
static bool is_tmpfs(struct mem_ops *ops)
{
return (ops == &__read_only_file_ops || ops == &__read_write_file_ops) &&
return (ops == &__read_only_file_ops ||
ops == &__read_write_file_read_ops ||
ops == &__read_write_file_write_ops) &&
finfo.type == VMA_SHMEM;
}
@ -554,9 +590,11 @@ static void __madvise_collapse(const char *msg, char *p, int nr_hpages,
printf("%s...", msg);
/* read&write file collapse always fail */
if (!is_tmpfs(ops) && ops == &__read_write_file_ops)
expect = false;
/*
* read&write file collapse succeeds for MADV_COLLAPSE because dirty
* folios are written back after collapse fails for dirty folios and
* another collapse is attempted.
*/
/*
* Prevent khugepaged interference and tests that MADV_COLLAPSE
@ -624,8 +662,11 @@ static bool wait_for_scan(const char *msg, char *p, int nr_hpages,
static void khugepaged_collapse(const char *msg, char *p, int nr_hpages,
struct mem_ops *ops, bool expect)
{
/* read&write file collapse always fail */
if (!is_tmpfs(ops) && ops == &__read_write_file_ops)
/*
* read&write file collapse fails since khugepaged does not flush
* the target dirty folios
*/
if (!is_tmpfs(ops) && ops == &__read_write_file_write_ops)
expect = false;
if (wait_for_scan(msg, p, nr_hpages, ops)) {
@ -748,6 +789,9 @@ static void collapse_max_ptes_none(struct collapse_context *c, struct mem_ops *o
validate_memory(p, 0, (hpage_pmd_nr - max_ptes_none - fault_nr_pages) * page_size);
if (c->enforce_pte_scan_limits) {
ops->cleanup_area(p, hpage_pmd_size);
p = ops->setup_area(1);
ops->fault(p, 0, (hpage_pmd_nr - max_ptes_none) * page_size);
c->collapse("Collapse with max_ptes_none PTEs empty", p, 1, ops,
true);
@ -1195,21 +1239,24 @@ static void parse_test_type(int argc, char **argv)
if (!strcmp(buf, "all")) {
read_only_file_ops = &__read_only_file_ops;
read_write_file_ops = &__read_write_file_ops;
read_write_file_read_ops = &__read_write_file_read_ops;
read_write_file_write_ops = &__read_write_file_write_ops;
anon_ops = &__anon_ops;
shmem_ops = &__shmem_ops;
} else if (!strcmp(buf, "anon")) {
anon_ops = &__anon_ops;
} else if (!strcmp(buf, "file")) {
read_only_file_ops = &__read_only_file_ops;
read_write_file_ops = &__read_write_file_ops;
read_write_file_read_ops = &__read_write_file_read_ops;
read_write_file_write_ops = &__read_write_file_write_ops;
} else if (!strcmp(buf, "shmem")) {
shmem_ops = &__shmem_ops;
} else {
usage();
}
if (!read_only_file_ops && !read_write_file_ops)
if (!read_only_file_ops && !read_write_file_read_ops &&
!read_write_file_write_ops)
return;
if (argc != 2)
@ -1282,11 +1329,13 @@ int main(int argc, char **argv)
TEST(collapse_full, khugepaged_context, anon_ops);
TEST(collapse_full, khugepaged_context, read_only_file_ops);
TEST(collapse_full, khugepaged_context, read_write_file_ops);
TEST(collapse_full, khugepaged_context, read_write_file_read_ops);
TEST(collapse_full, khugepaged_context, read_write_file_write_ops);
TEST(collapse_full, khugepaged_context, shmem_ops);
TEST(collapse_full, madvise_context, anon_ops);
TEST(collapse_full, madvise_context, read_only_file_ops);
TEST(collapse_full, madvise_context, read_write_file_ops);
TEST(collapse_full, madvise_context, read_write_file_read_ops);
TEST(collapse_full, madvise_context, read_write_file_write_ops);
TEST(collapse_full, madvise_context, shmem_ops);
TEST(collapse_empty, khugepaged_context, anon_ops);
@ -1294,30 +1343,38 @@ int main(int argc, char **argv)
TEST(collapse_single_pte_entry, khugepaged_context, anon_ops);
TEST(collapse_single_pte_entry, khugepaged_context, read_only_file_ops);
TEST(collapse_single_pte_entry, khugepaged_context, read_write_file_ops);
TEST(collapse_single_pte_entry, khugepaged_context, read_write_file_read_ops);
TEST(collapse_single_pte_entry, khugepaged_context, read_write_file_write_ops);
TEST(collapse_single_pte_entry, khugepaged_context, shmem_ops);
TEST(collapse_single_pte_entry, madvise_context, anon_ops);
TEST(collapse_single_pte_entry, madvise_context, read_only_file_ops);
TEST(collapse_single_pte_entry, madvise_context, read_write_file_ops);
TEST(collapse_single_pte_entry, madvise_context, read_write_file_read_ops);
TEST(collapse_single_pte_entry, madvise_context, read_write_file_write_ops);
TEST(collapse_single_pte_entry, madvise_context, shmem_ops);
TEST(collapse_max_ptes_none, khugepaged_context, anon_ops);
TEST(collapse_max_ptes_none, khugepaged_context, read_only_file_ops);
TEST(collapse_max_ptes_none, khugepaged_context, read_write_file_ops);
TEST(collapse_max_ptes_none, khugepaged_context, read_write_file_read_ops);
TEST(collapse_max_ptes_none, khugepaged_context, read_write_file_write_ops);
TEST(collapse_max_ptes_none, madvise_context, anon_ops);
TEST(collapse_max_ptes_none, madvise_context, read_only_file_ops);
TEST(collapse_max_ptes_none, madvise_context, read_write_file_ops);
TEST(collapse_max_ptes_none, madvise_context, read_write_file_read_ops);
TEST(collapse_max_ptes_none, madvise_context, read_write_file_write_ops);
TEST(collapse_single_pte_entry_compound, khugepaged_context, anon_ops);
TEST(collapse_single_pte_entry_compound, khugepaged_context, read_only_file_ops);
TEST(collapse_single_pte_entry_compound, khugepaged_context, read_write_file_read_ops);
TEST(collapse_single_pte_entry_compound, madvise_context, anon_ops);
TEST(collapse_single_pte_entry_compound, madvise_context, read_only_file_ops);
TEST(collapse_single_pte_entry_compound, madvise_context, read_write_file_read_ops);
TEST(collapse_full_of_compound, khugepaged_context, anon_ops);
TEST(collapse_full_of_compound, khugepaged_context, read_only_file_ops);
TEST(collapse_full_of_compound, khugepaged_context, read_write_file_read_ops);
TEST(collapse_full_of_compound, khugepaged_context, shmem_ops);
TEST(collapse_full_of_compound, madvise_context, anon_ops);
TEST(collapse_full_of_compound, madvise_context, read_only_file_ops);
TEST(collapse_full_of_compound, madvise_context, read_write_file_read_ops);
TEST(collapse_full_of_compound, madvise_context, shmem_ops);
TEST(collapse_compound_extreme, khugepaged_context, anon_ops);
@ -1340,9 +1397,11 @@ int main(int argc, char **argv)
TEST(madvise_collapse_existing_thps, madvise_context, anon_ops);
TEST(madvise_collapse_existing_thps, madvise_context, read_only_file_ops);
TEST(madvise_collapse_existing_thps, madvise_context, read_write_file_read_ops);
TEST(madvise_collapse_existing_thps, madvise_context, shmem_ops);
TEST(madvise_retracted_page_tables, madvise_context, read_only_file_ops);
TEST(madvise_retracted_page_tables, madvise_context, read_write_file_read_ops);
TEST(madvise_retracted_page_tables, madvise_context, shmem_ops);
restore_settings(0);