From d876678b5eb0db0df66a658faeb8fb71e236a634 Mon Sep 17 00:00:00 2001
From: antirez <antirez@gmail.com>
Date: Thu, 2 Feb 2012 10:17:16 +0100
Subject: [PATCH] Set a 3.5 GB maxmemory limit with noeviction policy if a 32
 bit instance without user-provided memory limits is detected.

---
 src/redis.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/redis.c b/src/redis.c
index 8dd35c4e..9f5aa4db 100644
--- a/src/redis.c
+++ b/src/redis.c
@@ -1095,6 +1095,16 @@ void initServer() {
         }
     }
 
+    /* 32 bit instances are limited to 4GB of address space, so if there is
+     * no explicit limit in the user provided configuration we set a limit
+     * at 3.5GB using maxmemory with 'noeviction' policy'. This saves
+     * useless crashes of the Redis instance. */
+    if (server.arch_bits == 32 && server.maxmemory == 0) {
+        redisLog(REDIS_WARNING,"Warning: 32 bit instance detected but no memory limit set. Setting 3.5 GB maxmemory limit with 'noeviction' policy now.");
+        server.maxmemory = 3584LL*(1024*1024); /* 3584 MB = 3.5 GB */
+        server.maxmemory_policy = REDIS_MAXMEMORY_NO_EVICTION;
+    }
+
     if (server.cluster_enabled) clusterInit();
     scriptingInit();
     slowlogInit();