From 60b831ef50e435b66ddd99e635a5112e121c7cb3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Zbigniew=20J=C4=99drzejewski-Szmek?= <zbyszek@in.waw.pl>
Date: Tue, 22 Jan 2019 15:43:07 +0100
Subject: [PATCH] procfs-util: expose functionality to query total memory

procfs_memory_get_current is renamed to procfs_memory_get_used, because
"current" can mean anything, including total memory, used memory, and free
memory, as long as the value is up to date.

No functional change.

(cherry-picked from commit c482724aa5c5d0b1391fcf958a9a3ea6ce73a085)

Related: #1664976
---
 src/basic/procfs-util.c     | 9 +++++----
 src/basic/procfs-util.h     | 5 ++++-
 src/cgtop/cgtop.c           | 2 +-
 src/core/cgroup.c           | 2 +-
 src/test/test-procfs-util.c | 2 +-
 5 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/basic/procfs-util.c b/src/basic/procfs-util.c
index a159e344b3..7aaf95bfce 100644
--- a/src/basic/procfs-util.c
+++ b/src/basic/procfs-util.c
@@ -201,13 +201,11 @@ int procfs_cpu_get_usage(nsec_t *ret) {
         return 0;
 }
 
-int procfs_memory_get_current(uint64_t *ret) {
+int procfs_memory_get(uint64_t *ret_total, uint64_t *ret_used) {
         uint64_t mem_total = UINT64_MAX, mem_free = UINT64_MAX;
         _cleanup_fclose_ FILE *f = NULL;
         int r;
 
-        assert(ret);
-
         f = fopen("/proc/meminfo", "re");
         if (!f)
                 return -errno;
@@ -262,6 +260,9 @@ int procfs_memory_get_current(uint64_t *ret) {
         if (mem_free > mem_total)
                 return -EINVAL;
 
-        *ret = (mem_total - mem_free) * 1024U;
+        if (ret_total)
+                *ret_total = mem_total * 1024U;
+        if (ret_used)
+                *ret_used = (mem_total - mem_free) * 1024U;
         return 0;
 }
diff --git a/src/basic/procfs-util.h b/src/basic/procfs-util.h
index f697ed92bc..5a44e9eff7 100644
--- a/src/basic/procfs-util.h
+++ b/src/basic/procfs-util.h
@@ -11,4 +11,7 @@ int procfs_tasks_get_current(uint64_t *ret);
 
 int procfs_cpu_get_usage(nsec_t *ret);
 
-int procfs_memory_get_current(uint64_t *ret);
+int procfs_memory_get(uint64_t *ret_total, uint64_t *ret_used);
+static inline int procfs_memory_get_used(uint64_t *ret) {
+        return procfs_memory_get(NULL, ret);
+}
diff --git a/src/cgtop/cgtop.c b/src/cgtop/cgtop.c
index 8dda08ab4c..792b13a43d 100644
--- a/src/cgtop/cgtop.c
+++ b/src/cgtop/cgtop.c
@@ -297,7 +297,7 @@ static int process(
         } else if (streq(controller, "memory")) {
 
                 if (is_root_cgroup(path)) {
-                        r = procfs_memory_get_current(&g->memory);
+                        r = procfs_memory_get_used(&g->memory);
                         if (r < 0)
                                 return r;
                 } else {
diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index bb02436203..62ab41a288 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -2402,7 +2402,7 @@ int unit_get_memory_current(Unit *u, uint64_t *ret) {
 
         /* The root cgroup doesn't expose this information, let's get it from /proc instead */
         if (unit_has_root_cgroup(u))
-                return procfs_memory_get_current(ret);
+                return procfs_memory_get_used(ret);
 
         if ((u->cgroup_realized_mask & CGROUP_MASK_MEMORY) == 0)
                 return -ENODATA;
diff --git a/src/test/test-procfs-util.c b/src/test/test-procfs-util.c
index 08af380cc7..1d0612985b 100644
--- a/src/test/test-procfs-util.c
+++ b/src/test/test-procfs-util.c
@@ -18,7 +18,7 @@ int main(int argc, char *argv[]) {
         assert_se(procfs_cpu_get_usage(&nsec) >= 0);
         log_info("Current system CPU time: %s", format_timespan(buf, sizeof(buf), nsec/NSEC_PER_USEC, 1));
 
-        assert_se(procfs_memory_get_current(&v) >= 0);
+        assert_se(procfs_memory_get_used(&v) >= 0);
         log_info("Current memory usage: %s", format_bytes(buf, sizeof(buf), v));
 
         assert_se(procfs_tasks_get_current(&v) >= 0);