Commit e2307ed6 authored Apr 22, 2015 by Thomas Graf Committed by David S. Miller Apr 22, 2015

rhashtable: Schedule async resize when sync realloc fails



When rhashtable_insert_rehash() fails with ENOMEM, this indicates that
we can't allocate the necessary memory in the current context but the
limits as set by the user would still allow to grow.

Thus attempt an async resize in the background where we can allocate
using GFP_KERNEL which is more likely to succeed. The insertion itself
will still fail to indicate pressure.

This fixes a bug where the table would never continue growing once the
utilization is above 100%.

Fixes: ccd57b1b ("rhashtable: Add immediate rehash during insertion")
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d83769a5

lib/rhashtable.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -410,8 +410,13 @@ int rhashtable_insert_rehash(struct rhashtable *ht)
		return -EBUSY;

		new_tbl = bucket_table_alloc(ht, size, GFP_ATOMIC);
		if (new_tbl == NULL)
		if (new_tbl == NULL) {
		/* Schedule async resize/rehash to try allocation
		* non-atomic context.
		*/
		schedule_work(&ht->run_work);
		return -ENOMEM;
		}

		err = rhashtable_rehash_attach(ht, tbl, new_tbl);
		if (err) {

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