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, 2 insertions, 0 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index 8c1ab8fb5012..4435d8b32904 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -3093,6 +3093,7 @@ static void __init dcache_init_early(void)
                                         HASH_EARLY,
                                         &d_hash_shift,
                                         &d_hash_mask,
+                                        0,
                                         0);
 
         for (loop = 0; loop < (1U << d_hash_shift); loop++)
@@ -3123,6 +3124,7 @@ static void __init dcache_init(void)
                                         0,
                                         &d_hash_shift,
                                         &d_hash_mask,
+                                        0,
                                         0);
 
         for (loop = 0; loop < (1U << d_hash_shift); loop++)