[LTP] [PATCH v3] syscalls/ioctl: ioctl_sg01.c: ioctl_sg01 invoked oom-killer

[Xinpeng Liu]

Kernel version is 5.4.81+,the available RAM is less than free,as follow:
[root@liuxp mywork]# head /proc/meminfo
MemTotal:       198101744 kB
MemFree:        189303148 kB
MemAvailable:   188566732 kB

So use available RAM to avoid OOM killer.
---
 lib/tst_memutils.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/tst_memutils.c b/lib/tst_memutils.c
index dd09db4..6b1173d 100644
--- a/lib/tst_memutils.c
+++ b/lib/tst_memutils.c
@@ -18,6 +18,7 @@ void tst_pollute_memory(size_t maxsize, int fillchar)
 	size_t i, map_count = 0, safety = 0, blocksize = BLOCKSIZE;
 	void **map_blocks;
 	struct sysinfo info;
+	unsigned long available_ram = 1024 * SAFE_READ_MEMINFO("MemAvailable:");
 
 	SAFE_SYSINFO(&info);
 	safety = MAX(4096 * SAFE_SYSCONF(_SC_PAGESIZE), 128 * 1024 * 1024);
@@ -26,15 +27,19 @@ void tst_pollute_memory(size_t maxsize, int fillchar)
 	if (info.freeswap > safety)
 		safety = 0;
 
+	/*"MemAvailable" field maybe not exist, or freeram less than available_ram*/
+	if(available_ram == 0 || info.freeram < available_ram)
+		available_ram = info.freeram;
+
 	/* Not enough free memory to avoid invoking OOM killer */
-	if (info.freeram <= safety)
+	if (available_ram <= safety)
 		return;
 
 	if (!maxsize)
 		maxsize = SIZE_MAX;
 
-	if (info.freeram - safety < maxsize / info.mem_unit)
-		maxsize = (info.freeram - safety) * info.mem_unit;
+	if (available_ram - safety < maxsize / info.mem_unit)
+		maxsize = (available_ram - safety) * info.mem_unit;
 
 	blocksize = MIN(maxsize, blocksize);
 	map_count = maxsize / blocksize;
-- 
1.8.3.1