rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation

When an rhashtable user pounds rhashtable hard with back-to-back
insertions we may end up growing the table in GFP_ATOMIC context.
Unfortunately when the table reaches a certain size this often
fails because we don't have enough physically contiguous pages
to hold the new table.

Eric Dumazet suggested (and in fact wrote this patch) using
__vmalloc instead which can be used in GFP_ATOMIC context.

Reported-by: Phil Sutter <phil@nwl.cc>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 3 insertions, 2 deletions

diff --git a/lib/rhashtable.c b/lib/rhashtable.c
index 2ff7ed91663a..1c624db90e88 100644
--- a/lib/rhashtable.c
+++ b/lib/rhashtable.c
@@ -120,8 +120,9 @@ static struct bucket_table *bucket_table_alloc(struct rhashtable *ht,
         if (size <= (PAGE_SIZE << PAGE_ALLOC_COSTLY_ORDER) ||
             gfp != GFP_KERNEL)
                 tbl = kzalloc(size, gfp | __GFP_NOWARN | __GFP_NORETRY);
-        if (tbl == NULL && gfp == GFP_KERNEL)
-                tbl = vzalloc(size);
+        if (tbl == NULL)
+                tbl = __vmalloc(size, gfp | __GFP_HIGHMEM | __GFP_ZERO,
+                                PAGE_KERNEL);
         if (tbl == NULL)
                 return NULL;