From: Herbert Xu <herb...@gondor.apana.org.au> Date: Thu, 3 Dec 2015 20:41:29 +0800
> Thomas and Phil observed that under stress rhashtable insertion > sometimes failed with EBUSY, even though this error should only > ever been seen when we're under attack and our hash chain length > has grown to an unacceptable level, even after a rehash. > > It turns out that the logic for detecting whether there is an > existing rehash is faulty. In particular, when two threads both > try to grow the same table at the same time, one of them may see > the newly grown table and thus erroneously conclude that it had > been rehashed. This is what leads to the EBUSY error. > > This patch fixes this by remembering the current last table we > used during insertion so that rhashtable_insert_rehash can detect > when another thread has also done a resize/rehash. When this is > detected we will give up our resize/rehash and simply retry the > insertion with the new table. > > Reported-by: Thomas Graf <tg...@suug.ch> > Reported-by: Phil Sutter <p...@nwl.cc> > Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au> Looks good, applied, thanks Herbert. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
