Re: [PATCH 2/6] lib/rhashtable: guarantee initial hashtable allocation

[Davidlohr Bueso]

On Mon, 28 May 2018, Herbert Xu wrote:

+       /*
+        * This is api initialization and thus we need to guarantee the
+        * initial rhashtable allocation. Upon failure, retry with a
+        * smallest possible size, otherwise we exhaust our options with
+        * __GFP_NOFAIL.
+        */
        tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
-       if (tbl == NULL)
-               return -ENOMEM;
+       if (unlikely(tbl == NULL)) {
+               size = HASH_MIN_SIZE;
+
+               tbl = bucket_table_alloc(ht, size, GFP_KERNEL);
+               if (tbl == NULL)
+                       tbl = bucket_table_alloc_retry(ht, size, GFP_KERNEL);
+       }

Perhaps you should also explain here why we don't just try the
minimum size with __GFP_NOFAIL as the second step rather than the
third.

Please see the comment above, I try to explain the rationale.

Thanks,
Davidlohr