rhashtable: Add nested tables
This patch adds code that handles GFP_ATOMIC kmalloc failure on insertion. As we cannot use vmalloc, we solve it by making our hash table nested. That is, we allocate single pages at each level and reach our desired table size by nesting them. When a nested table is created, only a single page is allocated at the top-level. Lower levels are allocated on demand during insertion. Therefore for each insertion to succeed, only two (non-consecutive) pages are needed. After a nested table is created, a rehash will be scheduled in order to switch to a vmalloced table as soon as possible. Also, the rehash code will never rehash into a nested table. If we detect a nested table during a rehash, the rehash will be aborted and a new rehash will be scheduled. Signed-off-by:Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by:
David S. Miller <davem@davemloft.net>
parent
40f9f439
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