]> www.infradead.org Git - users/dwmw2/linux.git/commitdiff
mm: huge_memory: enable debugfs to split huge pages to any order
authorZi Yan <ziy@nvidia.com>
Mon, 26 Feb 2024 20:55:34 +0000 (15:55 -0500)
committerAndrew Morton <akpm@linux-foundation.org>
Tue, 5 Mar 2024 01:01:20 +0000 (17:01 -0800)
It is used to test split_huge_page_to_list_to_order for pagecache THPs.
Also add test cases for split_huge_page_to_list_to_order via both debugfs.

[ziy@nvidia.com: fix issue discovered with NFS]
Link: https://lkml.kernel.org/r/262E4DAA-4A78-4328-B745-1355AE356A07@nvidia.com
Link: https://lkml.kernel.org/r/20240226205534.1603748-9-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Tested-by: Aishwarya TCV <aishwarya.tcv@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Cc: Aishwarya TCV <aishwarya.tcv@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/huge_memory.c
tools/testing/selftests/mm/run_vmtests.sh
tools/testing/selftests/mm/split_huge_page_test.c

index 006b192ea6ab9bb168875e917feab8d0499bfa13..fd745bcc97ff1dbfc3778d698a560412d2393a70 100644 (file)
@@ -3419,7 +3419,7 @@ static inline bool vma_not_suitable_for_thp_split(struct vm_area_struct *vma)
 }
 
 static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
-                               unsigned long vaddr_end)
+                               unsigned long vaddr_end, unsigned int new_order)
 {
        int ret = 0;
        struct task_struct *task;
@@ -3483,13 +3483,19 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
                        goto next;
 
                total++;
-               if (!can_split_folio(folio, NULL))
+               /*
+                * For folios with private, split_huge_page_to_list_to_order()
+                * will try to drop it before split and then check if the folio
+                * can be split or not. So skip the check here.
+                */
+               if (!folio_test_private(folio) &&
+                   !can_split_folio(folio, NULL))
                        goto next;
 
                if (!folio_trylock(folio))
                        goto next;
 
-               if (!split_folio(folio))
+               if (!split_folio_to_order(folio, new_order))
                        split++;
 
                folio_unlock(folio);
@@ -3507,7 +3513,7 @@ out:
 }
 
 static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
-                               pgoff_t off_end)
+                               pgoff_t off_end, unsigned int new_order)
 {
        struct filename *file;
        struct file *candidate;
@@ -3546,7 +3552,7 @@ static int split_huge_pages_in_file(const char *file_path, pgoff_t off_start,
                if (!folio_trylock(folio))
                        goto next;
 
-               if (!split_folio(folio))
+               if (!split_folio_to_order(folio, new_order))
                        split++;
 
                folio_unlock(folio);
@@ -3571,10 +3577,14 @@ static ssize_t split_huge_pages_write(struct file *file, const char __user *buf,
 {
        static DEFINE_MUTEX(split_debug_mutex);
        ssize_t ret;
-       /* hold pid, start_vaddr, end_vaddr or file_path, off_start, off_end */
+       /*
+        * hold pid, start_vaddr, end_vaddr, new_order or
+        * file_path, off_start, off_end, new_order
+        */
        char input_buf[MAX_INPUT_BUF_SZ];
        int pid;
        unsigned long vaddr_start, vaddr_end;
+       unsigned int new_order = 0;
 
        ret = mutex_lock_interruptible(&split_debug_mutex);
        if (ret)
@@ -3603,29 +3613,29 @@ static ssize_t split_huge_pages_write(struct file *file, const char __user *buf,
                        goto out;
                }
 
-               ret = sscanf(buf, "0x%lx,0x%lx", &off_start, &off_end);
-               if (ret != 2) {
+               ret = sscanf(buf, "0x%lx,0x%lx,%d", &off_start, &off_end, &new_order);
+               if (ret != 2 && ret != 3) {
                        ret = -EINVAL;
                        goto out;
                }
-               ret = split_huge_pages_in_file(file_path, off_start, off_end);
+               ret = split_huge_pages_in_file(file_path, off_start, off_end, new_order);
                if (!ret)
                        ret = input_len;
 
                goto out;
        }
 
-       ret = sscanf(input_buf, "%d,0x%lx,0x%lx", &pid, &vaddr_start, &vaddr_end);
+       ret = sscanf(input_buf, "%d,0x%lx,0x%lx,%d", &pid, &vaddr_start, &vaddr_end, &new_order);
        if (ret == 1 && pid == 1) {
                split_huge_pages_all();
                ret = strlen(input_buf);
                goto out;
-       } else if (ret != 3) {
+       } else if (ret != 3 && ret != 4) {
                ret = -EINVAL;
                goto out;
        }
 
-       ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end);
+       ret = split_huge_pages_pid(pid, vaddr_start, vaddr_end, new_order);
        if (!ret)
                ret = strlen(input_buf);
 out:
index de03d38907d62b8ba12dffbe1c73c9a98f6d6441..02dc1c38bd76b421bb5b346e0ef8e9b0835b006d 100755 (executable)
@@ -399,7 +399,27 @@ CATEGORY="thp" run_test ./khugepaged -s 2
 
 CATEGORY="thp" run_test ./transhuge-stress -d 20
 
-CATEGORY="thp" run_test ./split_huge_page_test
+# Try to create XFS if not provided
+if [ -z "${SPLIT_HUGE_PAGE_TEST_XFS_PATH}" ]; then
+    if test_selected "thp"; then
+        if grep xfs /proc/filesystems &>/dev/null; then
+            XFS_IMG=$(mktemp /tmp/xfs_img_XXXXXX)
+            SPLIT_HUGE_PAGE_TEST_XFS_PATH=$(mktemp -d /tmp/xfs_dir_XXXXXX)
+            truncate -s 314572800 ${XFS_IMG}
+            mkfs.xfs -q ${XFS_IMG}
+            mount -o loop ${XFS_IMG} ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
+            MOUNTED_XFS=1
+        fi
+    fi
+fi
+
+CATEGORY="thp" run_test ./split_huge_page_test ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
+
+if [ -n "${MOUNTED_XFS}" ]; then
+    umount ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
+    rmdir ${SPLIT_HUGE_PAGE_TEST_XFS_PATH}
+    rm -f ${XFS_IMG}
+fi
 
 CATEGORY="migration" run_test ./migration
 
index 7b698a848babf10f619de763dcdf7f1320ce30ad..856662d2f87a1b0db004c3e4297d3e5697424d62 100644 (file)
@@ -16,6 +16,7 @@
 #include <sys/mount.h>
 #include <malloc.h>
 #include <stdbool.h>
+#include <time.h>
 #include "vm_util.h"
 #include "../kselftest.h"
 
@@ -24,10 +25,11 @@ unsigned int pageshift;
 uint64_t pmd_pagesize;
 
 #define SPLIT_DEBUGFS "/sys/kernel/debug/split_huge_pages"
+#define SMAP_PATH "/proc/self/smaps"
 #define INPUT_MAX 80
 
-#define PID_FMT "%d,0x%lx,0x%lx"
-#define PATH_FMT "%s,0x%lx,0x%lx"
+#define PID_FMT "%d,0x%lx,0x%lx,%d"
+#define PATH_FMT "%s,0x%lx,0x%lx,%d"
 
 #define PFN_MASK     ((1UL<<55)-1)
 #define KPF_THP      (1UL<<22)
@@ -102,7 +104,7 @@ void split_pmd_thp(void)
 
        /* split all THPs */
        write_debugfs(PID_FMT, getpid(), (uint64_t)one_page,
-               (uint64_t)one_page + len);
+               (uint64_t)one_page + len, 0);
 
        for (i = 0; i < len; i++)
                if (one_page[i] != (char)i)
@@ -177,7 +179,7 @@ void split_pte_mapped_thp(void)
 
        /* split all remapped THPs */
        write_debugfs(PID_FMT, getpid(), (uint64_t)pte_mapped,
-                     (uint64_t)pte_mapped + pagesize * 4);
+                     (uint64_t)pte_mapped + pagesize * 4, 0);
 
        /* smap does not show THPs after mremap, use kpageflags instead */
        thp_size = 0;
@@ -237,7 +239,7 @@ void split_file_backed_thp(void)
        }
 
        /* split the file-backed THP */
-       write_debugfs(PATH_FMT, testfile, pgoff_start, pgoff_end);
+       write_debugfs(PATH_FMT, testfile, pgoff_start, pgoff_end, 0);
 
        status = unlink(testfile);
        if (status) {
@@ -265,8 +267,149 @@ cleanup:
        ksft_exit_fail_msg("Error occurred\n");
 }
 
+bool prepare_thp_fs(const char *xfs_path, char *thp_fs_template,
+               const char **thp_fs_loc)
+{
+       if (xfs_path) {
+               *thp_fs_loc = xfs_path;
+               return false;
+       }
+
+       *thp_fs_loc = mkdtemp(thp_fs_template);
+
+       if (!*thp_fs_loc)
+               ksft_exit_fail_msg("cannot create temp folder\n");
+
+       return true;
+}
+
+void cleanup_thp_fs(const char *thp_fs_loc, bool created_tmp)
+{
+       int status;
+
+       if (!created_tmp)
+               return;
+
+       status = rmdir(thp_fs_loc);
+       if (status)
+               ksft_exit_fail_msg("cannot remove tmp dir: %s\n",
+                                  strerror(errno));
+}
+
+int create_pagecache_thp_and_fd(const char *testfile, size_t fd_size, int *fd,
+               char **addr)
+{
+       size_t i;
+       int dummy;
+
+       srand(time(NULL));
+
+       *fd = open(testfile, O_CREAT | O_RDWR, 0664);
+       if (*fd == -1)
+               ksft_exit_fail_msg("Failed to create a file at %s\n", testfile);
+
+       for (i = 0; i < fd_size; i++) {
+               unsigned char byte = (unsigned char)i;
+
+               write(*fd, &byte, sizeof(byte));
+       }
+       close(*fd);
+       sync();
+       *fd = open("/proc/sys/vm/drop_caches", O_WRONLY);
+       if (*fd == -1) {
+               ksft_perror("open drop_caches");
+               goto err_out_unlink;
+       }
+       if (write(*fd, "3", 1) != 1) {
+               ksft_perror("write to drop_caches");
+               goto err_out_unlink;
+       }
+       close(*fd);
+
+       *fd = open(testfile, O_RDWR);
+       if (*fd == -1) {
+               ksft_perror("Failed to open testfile\n");
+               goto err_out_unlink;
+       }
+
+       *addr = mmap(NULL, fd_size, PROT_READ|PROT_WRITE, MAP_SHARED, *fd, 0);
+       if (*addr == (char *)-1) {
+               ksft_perror("cannot mmap");
+               goto err_out_close;
+       }
+       madvise(*addr, fd_size, MADV_HUGEPAGE);
+
+       for (size_t i = 0; i < fd_size; i++)
+               dummy += *(*addr + i);
+
+       if (!check_huge_file(*addr, fd_size / pmd_pagesize, pmd_pagesize)) {
+               ksft_print_msg("No large pagecache folio generated, please provide a filesystem supporting large folio\n");
+               munmap(*addr, fd_size);
+               close(*fd);
+               unlink(testfile);
+               ksft_test_result_skip("Pagecache folio split skipped\n");
+               return -2;
+       }
+       return 0;
+err_out_close:
+       close(*fd);
+err_out_unlink:
+       unlink(testfile);
+       ksft_exit_fail_msg("Failed to create large pagecache folios\n");
+       return -1;
+}
+
+void split_thp_in_pagecache_to_order(size_t fd_size, int order, const char *fs_loc)
+{
+       int fd;
+       char *addr;
+       size_t i;
+       char testfile[INPUT_MAX];
+       int err = 0;
+
+       err = snprintf(testfile, INPUT_MAX, "%s/test", fs_loc);
+
+       if (err < 0)
+               ksft_exit_fail_msg("cannot generate right test file name\n");
+
+       err = create_pagecache_thp_and_fd(testfile, fd_size, &fd, &addr);
+       if (err)
+               return;
+       err = 0;
+
+       write_debugfs(PID_FMT, getpid(), (uint64_t)addr, (uint64_t)addr + fd_size, order);
+
+       for (i = 0; i < fd_size; i++)
+               if (*(addr + i) != (char)i) {
+                       ksft_print_msg("%lu byte corrupted in the file\n", i);
+                       err = EXIT_FAILURE;
+                       goto out;
+               }
+
+       if (!check_huge_file(addr, 0, pmd_pagesize)) {
+               ksft_print_msg("Still FilePmdMapped not split\n");
+               err = EXIT_FAILURE;
+               goto out;
+       }
+
+out:
+       munmap(addr, fd_size);
+       close(fd);
+       unlink(testfile);
+       if (err)
+               ksft_exit_fail_msg("Split PMD-mapped pagecache folio to order %d failed\n", order);
+       ksft_test_result_pass("Split PMD-mapped pagecache folio to order %d passed\n", order);
+}
+
 int main(int argc, char **argv)
 {
+       int i;
+       size_t fd_size;
+       char *optional_xfs_path = NULL;
+       char fs_loc_template[] = "/tmp/thp_fs_XXXXXX";
+       const char *fs_loc;
+       bool created_tmp;
+
        ksft_print_header();
 
        if (geteuid() != 0) {
@@ -274,7 +417,10 @@ int main(int argc, char **argv)
                ksft_finished();
        }
 
-       ksft_set_plan(3);
+       if (argc > 1)
+               optional_xfs_path = argv[1];
+
+       ksft_set_plan(3+9);
 
        pagesize = getpagesize();
        pageshift = ffs(pagesize) - 1;
@@ -282,9 +428,19 @@ int main(int argc, char **argv)
        if (!pmd_pagesize)
                ksft_exit_fail_msg("Reading PMD pagesize failed\n");
 
+       fd_size = 2 * pmd_pagesize;
+
        split_pmd_thp();
        split_pte_mapped_thp();
        split_file_backed_thp();
 
+       created_tmp = prepare_thp_fs(optional_xfs_path, fs_loc_template,
+                       &fs_loc);
+       for (i = 8; i >= 0; i--)
+               split_thp_in_pagecache_to_order(fd_size, i, fs_loc);
+       cleanup_thp_fs(fs_loc, created_tmp);
+
        ksft_finished();
+
+       return 0;
 }