Add support for the memsw limits that limit memory+swap

Can be disabled in common.h in case your kernel does not support it.

cgroup.c

@@ -7,6 +7,13 @@
 #include <unistd.h>
 
 #include "cgroup.h"
+#include "common.h"
+
+#if SWAP_LIMIT
+#define MEMSW ".memsw"
+#else
+#define MEMSW
+#endif
 
 void (*cgroup_perror)(const char *s) = perror;
 static const char cgroupfs[] = "/sys/fs/cgroup/";
@@ -115,7 +122,7 @@ size_t
 cgroup_get_mem_limit(const char *chier, const char *cgroup)
 {
 	char limitfile[PATH_MAX];
-	snprintf(limitfile, sizeof(limitfile), "%s%s/%s/memory.limit_in_bytes", cgroupfs, chier, cgroup);
+	snprintf(limitfile, sizeof(limitfile), "%s%s/%s/memory"MEMSW".limit_in_bytes", cgroupfs, chier, cgroup);
 	FILE *limit = fopen(limitfile, "r");
 	if (!limit) {
 		cgroup_perror(limitfile);
@@ -128,10 +135,10 @@ cgroup_get_mem_limit(const char *chier, const char *cgroup)
 }
 
 int
-cgroup_set_mem_limit(const char *chier, const char *cgroup, size_t nlimit)
+cgroup_set_mem_limit_do(const char *chier, const char *cgroup, size_t nlimit, char *memsw)
 {
 	char limitfile[PATH_MAX];
-	snprintf(limitfile, sizeof(limitfile), "%s%s/%s/memory.limit_in_bytes", cgroupfs, chier, cgroup);
+	snprintf(limitfile, sizeof(limitfile), "%s%s/%s/memory%s.limit_in_bytes", cgroupfs, chier, cgroup, memsw);
 	FILE *limit = fopen(limitfile, "w");
 	if (!limit) {
 		cgroup_perror(limitfile);
@@ -142,11 +149,24 @@ cgroup_set_mem_limit(const char *chier, const char *cgroup, size_t nlimit)
 	return 1;
 }
 
+int
+cgroup_set_mem_limit(const char *chier, const char *cgroup, size_t nlimit)
+{
+	/* We need to set both the "normal" and memsw limits, normal first,
+	 * since normal <= memsw must hold. */
+	int ret = cgroup_set_mem_limit_do(chier, cgroup, nlimit, "");
+#if SWAP_LIMIT
+	if (ret >= 0)
+		ret |= cgroup_set_mem_limit_do(chier, cgroup, nlimit, MEMSW);
+#endif
+	return ret;
+}
+
 size_t
 cgroup_get_mem_usage(const char *chier, const char *cgroup)
 {
 	char usagefile[PATH_MAX];
-	snprintf(usagefile, sizeof(usagefile), "%s%s/%s/memory.usage_in_bytes", cgroupfs, chier, cgroup);
+	snprintf(usagefile, sizeof(usagefile), "%s%s/%s/memory"MEMSW".usage_in_bytes", cgroupfs, chier, cgroup);
 	FILE *usage = fopen(usagefile, "r");
 	if (!usage) {
 		cgroup_perror(usagefile);

common.h

@@ -18,6 +18,10 @@
 /* Default nice value for processes started using compctl --run. */
 #define COMPNICE 12
 
+/* Comment out if swap memory resource accounting is disabled
+ * and only RAM memory should be limited. */
+#define SWAP_LIMIT 1
+
 
 /* Other common definitions. */
 /* See README for the high-level protocol description. */