selftests/vm: dedup THP helpers

These files:

tools/testing/selftests/vm/vm_util.c
tools/testing/selftests/vm/khugepaged.c

Both contain logic to:

1) Determine hugepage size on current system
2) Read /proc/self/smaps to determine number of THPs at an address

Refactor selftests/vm/khugepaged.c to use the vm_util common helpers and
add it as a build dependency.

Since selftests/vm/khugepaged.c is the largest user of check_huge(),
change the signature of check_huge() to match selftests/vm/khugepaged.c's
useage: take an expected number of hugepages, and return a bool indicating
if the correct number of hugepages were found.  Add a wrapper,
check_huge_anon(), in anticipation of checking smaps for file and shmem
hugepages.

Update existing callsites to use the new pattern / function.

Likewise, check_for_pattern() was duplicated, and it's a general enough
helper to include in vm_util helpers as well.

Link: https://lkml.kernel.org/r/20220907144521.3115321-6-zokeefe@google.com
Link: https://lkml.kernel.org/r/20220922224046.1143204-6-zokeefe@google.com
Signed-off-by: Zach O'Keefe <zokeefe@google.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Chris Kennelly <ckennelly@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Rongwei Wang <rongwei.wang@linux.alibaba.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 7 insertions, 57 deletions

diff --git a/tools/testing/selftests/vm/khugepaged.c b/tools/testing/selftests/vm/khugepaged.c
index b55dc331af13..235a64b4458c 100644
--- a/tools/testing/selftests/vm/khugepaged.c
+++ b/tools/testing/selftests/vm/khugepaged.c
@@ -12,6 +12,8 @@
 #include <sys/mman.h>
 #include <sys/wait.h>
 
+#include "vm_util.h"
+
 #ifndef MADV_PAGEOUT
 #define MADV_PAGEOUT 21
 #endif
@@ -352,64 +354,12 @@ static void save_settings(void)
 	signal(SIGQUIT, restore_settings);
 }
 
-#define MAX_LINE_LENGTH 500
-
-static bool check_for_pattern(FILE *fp, char *pattern, char *buf)
-{
-	while (fgets(buf, MAX_LINE_LENGTH, fp) != NULL) {
-		if (!strncmp(buf, pattern, strlen(pattern)))
-			return true;
-	}
-	return false;
-}
-
 static bool check_huge(void *addr, int nr_hpages)
 {
-	bool thp = false;
-	int ret;
-	FILE *fp;
-	char buffer[MAX_LINE_LENGTH];
-	char addr_pattern[MAX_LINE_LENGTH];
-
-	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "%08lx-",
-		       (unsigned long) addr);
-	if (ret >= MAX_LINE_LENGTH) {
-		printf("%s: Pattern is too long\n", __func__);
-		exit(EXIT_FAILURE);
-	}
-
-
-	fp = fopen(PID_SMAPS, "r");
-	if (!fp) {
-		printf("%s: Failed to open file %s\n", __func__, PID_SMAPS);
-		exit(EXIT_FAILURE);
-	}
-	if (!check_for_pattern(fp, addr_pattern, buffer))
-		goto err_out;
-
-	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "AnonHugePages:%10ld kB",
-		       nr_hpages * (hpage_pmd_size >> 10));
-	if (ret >= MAX_LINE_LENGTH) {
-		printf("%s: Pattern is too long\n", __func__);
-		exit(EXIT_FAILURE);
-	}
-	/*
-	 * Fetch the AnonHugePages: in the same block and check whether it got
-	 * the expected number of hugeepages next.
-	 */
-	if (!check_for_pattern(fp, "AnonHugePages:", buffer))
-		goto err_out;
-
-	if (strncmp(buffer, addr_pattern, strlen(addr_pattern)))
-		goto err_out;
-
-	thp = true;
-err_out:
-	fclose(fp);
-	return thp;
+	return check_huge_anon(addr, nr_hpages, hpage_pmd_size);
 }
 
-
+#define MAX_LINE_LENGTH 500
 static bool check_swap(void *addr, unsigned long size)
 {
 	bool swap = false;
@@ -431,7 +381,7 @@ static bool check_swap(void *addr, unsigned long size)
 		printf("%s: Failed to open file %s\n", __func__, PID_SMAPS);
 		exit(EXIT_FAILURE);
 	}
-	if (!check_for_pattern(fp, addr_pattern, buffer))
+	if (!check_for_pattern(fp, addr_pattern, buffer, sizeof(buffer)))
 		goto err_out;
 
 	ret = snprintf(addr_pattern, MAX_LINE_LENGTH, "Swap:%19ld kB",
@@ -444,7 +394,7 @@ static bool check_swap(void *addr, unsigned long size)
 	 * Fetch the Swap: in the same block and check whether it got
 	 * the expected number of hugeepages next.
 	 */
-	if (!check_for_pattern(fp, "Swap:", buffer))
+	if (!check_for_pattern(fp, "Swap:", buffer, sizeof(buffer)))
 		goto err_out;
 
 	if (strncmp(buffer, addr_pattern, strlen(addr_pattern)))
@@ -1066,7 +1016,7 @@ int main(int argc, const char **argv)
 	setbuf(stdout, NULL);
 
 	page_size = getpagesize();
-	hpage_pmd_size = read_num("hpage_pmd_size");
+	hpage_pmd_size = read_pmd_pagesize();
 	hpage_pmd_nr = hpage_pmd_size / page_size;
 
 	default_settings.khugepaged.max_ptes_none = hpage_pmd_nr - 1;