Merge tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:

 - Daniel Verkamp has contributed a memfd series ("mm/memfd: add
   F_SEAL_EXEC") which permits the setting of the memfd execute bit at
   memfd creation time, with the option of sealing the state of the X
   bit.

 - Peter Xu adds a patch series ("mm/hugetlb: Make huge_pte_offset()
   thread-safe for pmd unshare") which addresses a rare race condition
   related to PMD unsharing.

 - Several folioification patch serieses from Matthew Wilcox, Vishal
   Moola, Sidhartha Kumar and Lorenzo Stoakes

 - Johannes Weiner has a series ("mm: push down lock_page_memcg()")
   which does perform some memcg maintenance and cleanup work.

 - SeongJae Park has added DAMOS filtering to DAMON, with the series
   "mm/damon/core: implement damos filter".

   These filters provide users with finer-grained control over DAMOS's
   actions. SeongJae has also done some DAMON cleanup work.

 - Kairui Song adds a series ("Clean up and fixes for swap").

 - Vernon Yang contributed the series "Clean up and refinement for maple
   tree".

 - Yu Zhao has contributed the "mm: multi-gen LRU: memcg LRU" series. It
   adds to MGLRU an LRU of memcgs, to improve the scalability of global
   reclaim.

 - David Hildenbrand has added some userfaultfd cleanup work in the
   series "mm: uffd-wp + change_protection() cleanups".

 - Christoph Hellwig has removed the generic_writepages() library
   function in the series "remove generic_writepages".

 - Baolin Wang has performed some maintenance on the compaction code in
   his series "Some small improvements for compaction".

 - Sidhartha Kumar is doing some maintenance work on struct page in his
   series "Get rid of tail page fields".

 - David Hildenbrand contributed some cleanup, bugfixing and
   generalization of pte management and of pte debugging in his series
   "mm: support __HAVE_ARCH_PTE_SWP_EXCLUSIVE on all architectures with
   swap PTEs".

 - Mel Gorman and Neil Brown have removed the __GFP_ATOMIC allocation
   flag in the series "Discard __GFP_ATOMIC".

 - Sergey Senozhatsky has improved zsmalloc's memory utilization with
   his series "zsmalloc: make zspage chain size configurable".

 - Joey Gouly has added prctl() support for prohibiting the creation of
   writeable+executable mappings.

   The previous BPF-based approach had shortcomings. See "mm: In-kernel
   support for memory-deny-write-execute (MDWE)".

 - Waiman Long did some kmemleak cleanup and bugfixing in the series
   "mm/kmemleak: Simplify kmemleak_cond_resched() & fix UAF".

 - T.J. Alumbaugh has contributed some MGLRU cleanup work in his series
   "mm: multi-gen LRU: improve".

 - Jiaqi Yan has provided some enhancements to our memory error
   statistics reporting, mainly by presenting the statistics on a
   per-node basis. See the series "Introduce per NUMA node memory error
   statistics".

 - Mel Gorman has a second and hopefully final shot at fixing a CPU-hog
   regression in compaction via his series "Fix excessive CPU usage
   during compaction".

 - Christoph Hellwig does some vmalloc maintenance work in the series
   "cleanup vfree and vunmap".

 - Christoph Hellwig has removed block_device_operations.rw_page() in
   ths series "remove ->rw_page".

 - We get some maple_tree improvements and cleanups in Liam Howlett's
   series "VMA tree type safety and remove __vma_adjust()".

 - Suren Baghdasaryan has done some work on the maintainability of our
   vm_flags handling in the series "introduce vm_flags modifier
   functions".

 - Some pagemap cleanup and generalization work in Mike Rapoport's
   series "mm, arch: add generic implementation of pfn_valid() for
   FLATMEM" and "fixups for generic implementation of pfn_valid()"

 - Baoquan He has done some work to make /proc/vmallocinfo and
   /proc/kcore better represent the real state of things in his series
   "mm/vmalloc.c: allow vread() to read out vm_map_ram areas".

 - Jason Gunthorpe rationalized the GUP system's interface to the rest
   of the kernel in the series "Simplify the external interface for
   GUP".

 - SeongJae Park wishes to migrate people from DAMON's debugfs interface
   over to its sysfs interface. To support this, we'll temporarily be
   printing warnings when people use the debugfs interface. See the
   series "mm/damon: deprecate DAMON debugfs interface".

 - Andrey Konovalov provided the accurately named "lib/stackdepot: fixes
   and clean-ups" series.

 - Huang Ying has provided a dramatic reduction in migration's TLB flush
   IPI rates with the series "migrate_pages(): batch TLB flushing".

 - Arnd Bergmann has some objtool fixups in "objtool warning fixes".

* tag 'mm-stable-2023-02-20-13-37' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (505 commits)
  include/linux/migrate.h: remove unneeded externs
  mm/memory_hotplug: cleanup return value handing in do_migrate_range()
  mm/uffd: fix comment in handling pte markers
  mm: change to return bool for isolate_movable_page()
  mm: hugetlb: change to return bool for isolate_hugetlb()
  mm: change to return bool for isolate_lru_page()
  mm: change to return bool for folio_isolate_lru()
  objtool: add UACCESS exceptions for __tsan_volatile_read/write
  kmsan: disable ftrace in kmsan core code
  kasan: mark addr_has_metadata __always_inline
  mm: memcontrol: rename memcg_kmem_enabled()
  sh: initialize max_mapnr
  m68k/nommu: add missing definition of ARCH_PFN_OFFSET
  mm: percpu: fix incorrect size in pcpu_obj_full_size()
  maple_tree: reduce stack usage with gcc-9 and earlier
  mm: page_alloc: call panic() when memoryless node allocation fails
  mm: multi-gen LRU: avoid futile retries
  migrate_pages: move THP/hugetlb migration support check to simplify code
  migrate_pages: batch flushing TLB
  migrate_pages: share more code between _unmap and _move
  ...

1 files changed, 309 insertions, 0 deletions

diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
new file mode 100644
index 000000000000..76e1c36dd9e5
--- /dev/null
+++ b/tools/testing/selftests/mm/split_huge_page_test.c
@@ -0,0 +1,309 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * A test of splitting PMD THPs and PTE-mapped THPs from a specified virtual
+ * address range in a process via <debugfs>/split_huge_pages interface.
+ */
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdarg.h>
+#include <unistd.h>
+#include <inttypes.h>
+#include <string.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <malloc.h>
+#include <stdbool.h>
+#include "vm_util.h"
+
+uint64_t pagesize;
+unsigned int pageshift;
+uint64_t pmd_pagesize;
+
+#define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages"
+#define INPUT_MAX 80
+
+#define PID_FMT "%d,0x%lx,0x%lx"
+#define PATH_FMT "%s,0x%lx,0x%lx"
+
+#define PFN_MASK     ((1UL<<55)-1)
+#define KPF_THP      (1UL<<22)
+
+int is_backed_by_thp(char *vaddr, int pagemap_file, int kpageflags_file)
+{
+	uint64_t paddr;
+	uint64_t page_flags;
+
+	if (pagemap_file) {
+		pread(pagemap_file, &paddr, sizeof(paddr),
+			((long)vaddr >> pageshift) * sizeof(paddr));
+
+		if (kpageflags_file) {
+			pread(kpageflags_file, &page_flags, sizeof(page_flags),
+				(paddr & PFN_MASK) * sizeof(page_flags));
+
+			return !!(page_flags & KPF_THP);
+		}
+	}
+	return 0;
+}
+
+static int write_file(const char *path, const char *buf, size_t buflen)
+{
+	int fd;
+	ssize_t numwritten;
+
+	fd = open(path, O_WRONLY);
+	if (fd == -1)
+		return 0;
+
+	numwritten = write(fd, buf, buflen - 1);
+	close(fd);
+	if (numwritten < 1)
+		return 0;
+
+	return (unsigned int) numwritten;
+}
+
+static void write_debugfs(const char *fmt, ...)
+{
+	char input[INPUT_MAX];
+	int ret;
+	va_list argp;
+
+	va_start(argp, fmt);
+	ret = vsnprintf(input, INPUT_MAX, fmt, argp);
+	va_end(argp);
+
+	if (ret >= INPUT_MAX) {
+		printf("%s: Debugfs input is too long\n", __func__);
+		exit(EXIT_FAILURE);
+	}
+
+	if (!write_file(SPLIT_DEBUGFS, input, ret + 1)) {
+		perror(SPLIT_DEBUGFS);
+		exit(EXIT_FAILURE);
+	}
+}
+
+void split_pmd_thp(void)
+{
+	char *one_page;
+	size_t len = 4 * pmd_pagesize;
+	size_t i;
+
+	one_page = memalign(pmd_pagesize, len);
+
+	if (!one_page) {
+		printf("Fail to allocate memory\n");
+		exit(EXIT_FAILURE);
+	}
+
+	madvise(one_page, len, MADV_HUGEPAGE);
+
+	for (i = 0; i < len; i++)
+		one_page[i] = (char)i;
+
+	if (!check_huge_anon(one_page, 1, pmd_pagesize)) {
+		printf("No THP is allocated\n");
+		exit(EXIT_FAILURE);
+	}
+
+	/* split all THPs */
+	write_debugfs(PID_FMT, getpid(), (uint64_t)one_page,
+		(uint64_t)one_page + len);
+
+	for (i = 0; i < len; i++)
+		if (one_page[i] != (char)i) {
+			printf("%ld byte corrupted\n", i);
+			exit(EXIT_FAILURE);
+		}
+
+
+	if (check_huge_anon(one_page, 0, pmd_pagesize)) {
+		printf("Still AnonHugePages not split\n");
+		exit(EXIT_FAILURE);
+	}
+
+	printf("Split huge pages successful\n");
+	free(one_page);
+}
+
+void split_pte_mapped_thp(void)
+{
+	char *one_page, *pte_mapped, *pte_mapped2;
+	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) {
+		perror("get pagemap proc error");
+		exit(EXIT_FAILURE);
+	}
+	pagemap_fd = open(pagemap_proc, O_RDONLY);
+
+	if (pagemap_fd == -1) {
+		perror("read pagemap:");
+		exit(EXIT_FAILURE);
+	}
+
+	kpageflags_fd = open(kpageflags_proc, O_RDONLY);
+
+	if (kpageflags_fd == -1) {
+		perror("read kpageflags:");
+		exit(EXIT_FAILURE);
+	}
+
+	one_page = mmap((void *)(1UL << 30), len, PROT_READ | PROT_WRITE,
+			MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
+
+	madvise(one_page, len, MADV_HUGEPAGE);
+
+	for (i = 0; i < len; i++)
+		one_page[i] = (char)i;
+
+	if (!check_huge_anon(one_page, 1, pmd_pagesize)) {
+		printf("No THP is allocated\n");
+		exit(EXIT_FAILURE);
+	}
+
+	/* remap the first pagesize of first THP */
+	pte_mapped = mremap(one_page, pagesize, pagesize, MREMAP_MAYMOVE);
+
+	/* remap the Nth pagesize of Nth THP */
+	for (i = 1; i < 4; i++) {
+		pte_mapped2 = mremap(one_page + pmd_pagesize * i + pagesize * i,
+				     pagesize, pagesize,
+				     MREMAP_MAYMOVE|MREMAP_FIXED,
+				     pte_mapped + pagesize * i);
+		if (pte_mapped2 == (char *)-1) {
+			perror("mremap failed");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	/* smap does not show THPs after mremap, use kpageflags instead */
+	thp_size = 0;
+	for (i = 0; i < pagesize * 4; i++)
+		if (i % pagesize == 0 &&
+		    is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd))
+			thp_size++;
+
+	if (thp_size != 4) {
+		printf("Some THPs are missing during mremap\n");
+		exit(EXIT_FAILURE);
+	}
+
+	/* split all remapped THPs */
+	write_debugfs(PID_FMT, getpid(), (uint64_t)pte_mapped,
+		      (uint64_t)pte_mapped + pagesize * 4);
+
+	/* smap does not show THPs after mremap, use kpageflags instead */
+	thp_size = 0;
+	for (i = 0; i < pagesize * 4; i++) {
+		if (pte_mapped[i] != (char)i) {
+			printf("%ld byte corrupted\n", i);
+			exit(EXIT_FAILURE);
+		}
+		if (i % pagesize == 0 &&
+		    is_backed_by_thp(&pte_mapped[i], pagemap_fd, kpageflags_fd))
+			thp_size++;
+	}
+
+	if (thp_size) {
+		printf("Still %ld THPs not split\n", thp_size);
+		exit(EXIT_FAILURE);
+	}
+
+	printf("Split PTE-mapped huge pages successful\n");
+	munmap(one_page, len);
+	close(pagemap_fd);
+	close(kpageflags_fd);
+}
+
+void split_file_backed_thp(void)
+{
+	int status;
+	int fd;
+	ssize_t num_written;
+	char tmpfs_template[] = "/tmp/thp_split_XXXXXX";
+	const char *tmpfs_loc = mkdtemp(tmpfs_template);
+	char testfile[INPUT_MAX];
+	uint64_t pgoff_start = 0, pgoff_end = 1024;
+
+	printf("Please enable pr_debug in split_huge_pages_in_file() if you need more info.\n");
+
+	status = mount("tmpfs", tmpfs_loc, "tmpfs", 0, "huge=always,size=4m");
+
+	if (status) {
+		printf("Unable to create a tmpfs for testing\n");
+		exit(EXIT_FAILURE);
+	}
+
+	status = snprintf(testfile, INPUT_MAX, "%s/thp_file", tmpfs_loc);
+	if (status >= INPUT_MAX) {
+		printf("Fail to create file-backed THP split testing file\n");
+		goto cleanup;
+	}
+
+	fd = open(testfile, O_CREAT|O_WRONLY);
+	if (fd == -1) {
+		perror("Cannot open testing file\n");
+		goto cleanup;
+	}
+
+	/* write something to the file, so a file-backed THP can be allocated */
+	num_written = write(fd, tmpfs_loc, strlen(tmpfs_loc) + 1);
+	close(fd);
+
+	if (num_written < 1) {
+		printf("Fail to write data to testing file\n");
+		goto cleanup;
+	}
+
+	/* split the file-backed THP */
+	write_debugfs(PATH_FMT, testfile, pgoff_start, pgoff_end);
+
+	status = unlink(testfile);
+	if (status)
+		perror("Cannot remove testing file\n");
+
+cleanup:
+	status = umount(tmpfs_loc);
+	if (status) {
+		printf("Unable to umount %s\n", tmpfs_loc);
+		exit(EXIT_FAILURE);
+	}
+	status = rmdir(tmpfs_loc);
+	if (status) {
+		perror("cannot remove tmp dir");
+		exit(EXIT_FAILURE);
+	}
+
+	printf("file-backed THP split test done, please check dmesg for more information\n");
+}
+
+int main(int argc, char **argv)
+{
+	if (geteuid() != 0) {
+		printf("Please run the benchmark as root\n");
+		exit(EXIT_FAILURE);
+	}
+
+	pagesize = getpagesize();
+	pageshift = ffs(pagesize) - 1;
+	pmd_pagesize = read_pmd_pagesize();
+
+	split_pmd_thp();
+	split_pte_mapped_thp();
+	split_file_backed_thp();
+
+	return 0;
+}