1 files changed, 57 insertions, 0 deletions
diff --git a/src/zmalloc.c b/src/zmalloc.c
index 6df51a80f..640ee19e2 100644
--- a/src/zmalloc.c
+++ b/src/zmalloc.c
@@ -364,3 +364,60 @@ size_t zmalloc_get_smap_bytes_by_field(char *field) {
 size_t zmalloc_get_private_dirty(void) {
     return zmalloc_get_smap_bytes_by_field("Private_Dirty:");
 }
+
+/* Returns the size of physical memory (RAM) in bytes.
+ * It looks ugly, but this is the cleanest way to achive cross platform results.
+ * Cleaned up from:
+ *
+ * http://nadeausoftware.com/articles/2012/09/c_c_tip_how_get_physical_memory_size_system
+ *
+ * Note that this function:
+ * 1) Was released under the following CC attribution license:
+ *    http://creativecommons.org/licenses/by/3.0/deed.en_US.
+ * 2) Was originally implemented by David Robert Nadeau.
+ * 3) Was modified for Redis by Matt Stancliff.
+ * 4) This note exists in order to comply with the original license.
+ */
+size_t zmalloc_get_memory_size(void) {
+#if defined(__unix__) || defined(__unix) || defined(unix) || \
+    (defined(__APPLE__) && defined(__MACH__))
+#if defined(CTL_HW) && (defined(HW_MEMSIZE) || defined(HW_PHYSMEM64))
+    int mib[2];
+    mib[0] = CTL_HW;
+#if defined(HW_MEMSIZE)
+    mib[1] = HW_MEMSIZE;            /* OSX. --------------------- */
+#elif defined(HW_PHYSMEM64)
+    mib[1] = HW_PHYSMEM64;          /* NetBSD, OpenBSD. --------- */
+#endif
+    int64_t size = 0;               /* 64-bit */
+    size_t len = sizeof(size);
+    if (sysctl( mib, 2, &size, &len, NULL, 0) == 0)
+        return (size_t)size;
+    return 0L;          /* Failed? */
+
+#elif defined(_SC_PHYS_PAGES) && defined(_SC_PAGESIZE)
+    /* FreeBSD, Linux, OpenBSD, and Solaris. -------------------- */
+    return (size_t)sysconf(_SC_PHYS_PAGES) * (size_t)sysconf(_SC_PAGESIZE);
+
+#elif defined(CTL_HW) && (defined(HW_PHYSMEM) || defined(HW_REALMEM))
+    /* DragonFly BSD, FreeBSD, NetBSD, OpenBSD, and OSX. -------- */
+    int mib[2];
+    mib[0] = CTL_HW;
+#if defined(HW_REALMEM)
+    mib[1] = HW_REALMEM;        /* FreeBSD. ----------------- */
+#elif defined(HW_PYSMEM)
+    mib[1] = HW_PHYSMEM;        /* Others. ------------------ */
+#endif
+    unsigned int size = 0;      /* 32-bit */
+    size_t len = sizeof(size);
+    if (sysctl(mib, 2, &size, &len, NULL, 0) == 0)
+        return (size_t)size;
+    return 0L;          /* Failed? */
+#endif /* sysctl and sysconf variants */
+
+#else
+    return 0L;          /* Unknown OS. */
+#endif
+}
+
+