diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index a0909c79374b..51a068ad064b 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -292,8 +292,8 @@ static inline int ip6_frag_mem(struct net *net)
 }
 #endif
 
-#define IPV6_FRAG_HIGH_THRESH	(256 * 1024)	/* 262144 */
-#define IPV6_FRAG_LOW_THRESH	(192 * 1024)	/* 196608 */
+#define IPV6_FRAG_HIGH_THRESH	(4 * 1024*1024)	/* 4194304 */
+#define IPV6_FRAG_LOW_THRESH	(3 * 1024*1024)	/* 3145728 */
 #define IPV6_FRAG_TIMEOUT	(60 * HZ)	/* 60 seconds */
 
 extern int __ipv6_addr_type(const struct in6_addr *addr);
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index eb9d63a570cd..f55a4e61bfb8 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -851,14 +851,22 @@ static inline void ip4_frags_ctl_register(void)
 
 static int __net_init ipv4_frags_init_net(struct net *net)
 {
-	/*
-	 * Fragment cache limits. We will commit 256K at one time. Should we
-	 * cross that limit we will prune down to 192K. This should cope with
-	 * even the most extreme cases without allowing an attacker to
-	 * measurably harm machine performance.
+	/* Fragment cache limits.
+	 *
+	 * The fragment memory accounting code, (tries to) account for
+	 * the real memory usage, by measuring both the size of frag
+	 * queue struct (inet_frag_queue (ipv4:ipq/ipv6:frag_queue))
+	 * and the SKB's truesize.
+	 *
+	 * A 64K fragment consumes 129736 bytes (44*2944)+200
+	 * (1500 truesize == 2944, sizeof(struct ipq) == 200)
+	 *
+	 * We will commit 4MB at one time. Should we cross that limit
+	 * we will prune down to 3MB, making room for approx 8 big 64K
+	 * fragments 8x128k.
 	 */
-	net->ipv4.frags.high_thresh = 256 * 1024;
-	net->ipv4.frags.low_thresh = 192 * 1024;
+	net->ipv4.frags.high_thresh = 4 * 1024 * 1024;
+	net->ipv4.frags.low_thresh  = 3 * 1024 * 1024;
 	/*
 	 * Important NOTE! Fragment queue must be destroyed before MSL expires.
 	 * RFC791 is wrong proposing to prolongate timer each fragment arrival