mm: add a low limit to alloc_large_system_hash

UDP stack needs a minimum hash size value for proper operation and also
uses alloc_large_system_hash() for proper NUMA distribution of its hash
tables and automatic sizing depending on available system memory.

On some low memory situations, udp_table_init() must ignore the
alloc_large_system_hash() result and reallocs a bigger memory area.

As we cannot easily free old hash table, we leak it and kmemleak can
issue a warning.

This patch adds a low limit parameter to alloc_large_system_hash() to
solve this problem.

We then specify UDP_HTABLE_SIZE_MIN for UDP/UDPLite hash table
allocation.

Reported-by: Mark Asselstine <mark.asselstine@windriver.com>
Reported-by: Tim Bird <tim.bird@am.sony.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 0 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index ffcb3b016843..98b30d08efe9 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3452,6 +3452,7 @@ int __init ip_rt_init(void)
                                         0,
                                         &rt_hash_log,
                                         &rt_hash_mask,
+                                        0,
                                         rhash_entries ? 0 : 512 * 1024);
         memset(rt_hash_table, 0, (rt_hash_mask + 1) * sizeof(struct rt_hash_bucket));
         rt_hash_lock_init();