[LTP] [PATCH] mmap2: change memory units and default size

[Julio Cruz]

This patch made three changes: 1) check the available memory 
before to perform the test case, 2) change the memory units
from GB to MB, and 3)  make default file size to 128M.

These changes are needed during testing on embedded devices
with RAM memory limitation (i.e. 512MB).

This patch no changed the test case procedure.

To use this test case in embedded devices, I suggest to change 
the testrun 'mm' as below from: "mtest06_2 mmap2 -x 0.002 -a -p" 
to "mtest06_2 mmap2 -x 0.002 -a -p -s 100" according with 
your system memory available

Signed-off-by: Julio Cruz <jcsistemas2001@gmail.com>
---
 testcases/kernel/mem/mtest06/mmap2.c | 40 +++++++++++++++++++++++++-----------
 1 file changed, 28 insertions(+), 12 deletions(-)

diff --git a/testcases/kernel/mem/mtest06/mmap2.c b/testcases/kernel/mem/mtest06/mmap2.c
index ad81dbe..ebeebe5 100644
--- a/testcases/kernel/mem/mtest06/mmap2.c
+++ b/testcases/kernel/mem/mtest06/mmap2.c
@@ -48,9 +48,9 @@
 /*									      */
 /* Description: Test the LINUX memory manager. The program is aimed at        */
 /*              stressing the memory manager by repeaded map/write/unmap of a */
-/*		of a large gb size file.				      */
+/*		large mb size file.				              */
 /*									      */
-/*		Create a file of the specified size in gb, map the file,      */
+/*		Create a file of the specified size in mb, map the file,      */
 /*		change the contents of the file and unmap it. This is repeated*/
 /*		several times for the specified number of hours.	      */
 /*									      */
@@ -73,7 +73,7 @@
 #include <getopt.h>
 #include "test.h"
 
-#define GB 1000000000
+#define MB 1048576
 #ifndef TRUE
 #define TRUE 1
 #endif
@@ -99,7 +99,7 @@ static int mkfile(int size)
 		fprintf(stdout, "creating tmp file and writing 'a' to it ");
 	}
 
-	while (index < (size * GB)) {
+	while (index < (size * MB)) {
 		index += 4096;
 		if (write(fd, buff, 4096) == -1) {
 			perror("mkfile(): write()");
@@ -136,16 +136,24 @@ static void usage(char *progname)
 		"\t -p set map_flag to MAP_PRIVATE.\tdefault:"
 		"MAP_SHARED\n"
 		"\t -s size of the file/memory to be mmaped.\tdefault:"
-		"1GB\n"
+		"128MB\n"
 		"\t -x time for which test is to be run.\tdefault:"
 		"24 Hrs\n", progname);
 	exit(-1);
 }
 
+long get_available_memory_mb(void)
+{
+	unsigned long long ps, pn;
+	ps = sysconf(_SC_PAGESIZE);
+	pn = sysconf(_SC_AVPHYS_PAGES);
+	return ps * pn / (1024*1024);
+}
+
 int main(int argc, char **argv)
 {
 	int fd;
-	int fsize = 1;
+	int fsize = 128;
 	float exec_time = 24;
 	int c;
 	int sig_ndx;
@@ -153,6 +161,7 @@ int main(int argc, char **argv)
 	int map_anon = FALSE;
 	int run_once = TRUE;
 	char *memptr;
+	long avail_memory_mb;
 	struct sigaction sigptr;
 
 	static struct signal_info {
@@ -188,7 +197,7 @@ int main(int argc, char **argv)
 			fsize = atoi(optarg);
 			if (fsize == 0)
 				fprintf(stderr, "Using default "
-					"fsize %d GB\n", fsize = 1);
+					"fsize %d MB\n", fsize = 128);
 			break;
 		case 'x':
 			exec_time = atof(optarg);
@@ -205,7 +214,14 @@ int main(int argc, char **argv)
 
 	fprintf(stdout, "MM Stress test, map/write/unmap large file\n"
 		"\tTest scheduled to run for:       %f\n"
-		"\tSize of temp file in GB:         %d\n", exec_time, fsize);
+		"\tSize of temp file in MB:         %d\n", exec_time, fsize);
+
+	avail_memory_mb = get_available_memory_mb();
+	fprintf(stdout, "Available memory: %ldMB\n", avail_memory_mb);
+	if (fsize > avail_memory_mb) {
+		fprintf(stdout, "Not enough memory to run this case\n");
+		exit(0);
+	}
 
 	alarm(exec_time * 3600.00);
 
@@ -235,7 +251,7 @@ int main(int argc, char **argv)
 			fd = -1;
 			map_flags = map_flags | MAP_ANONYMOUS;
 		}
-		memptr = mmap(0, (fsize * GB), PROT_READ | PROT_WRITE,
+		memptr = mmap(0, (fsize * MB), PROT_READ | PROT_WRITE,
 			      map_flags, fd, 0);
 		if (memptr == MAP_FAILED) {
 			perror("main(): mmap()");
@@ -244,15 +260,15 @@ int main(int argc, char **argv)
 			fprintf(stdout, "file mapped at %p\n"
 				"changing file content to 'A'\n", memptr);
 
-		memset(memptr, 'A', ((fsize * GB) / sizeof(char)));
+		memset(memptr, 'A', ((fsize * MB) / sizeof(char)));
 
-		if (msync(memptr, ((fsize * GB) / sizeof(char)),
+		if (msync(memptr, ((fsize * MB) / sizeof(char)),
 			  MS_SYNC | MS_INVALIDATE) == -1) {
 			perror("main(): msync()");
 			exit(-1);
 		}
 
-		if (munmap(memptr, (fsize * GB) / sizeof(char)) == -1) {
+		if (munmap(memptr, (fsize * MB) / sizeof(char)) == -1) {
 			perror("main(): munmap()");
 			exit(-1);
 		} else
-- 
1.9.1