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From: Xin Long <lucien.xin@gmail.com>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Phil Sutter <phil@nwl.cc>, davem <davem@davemloft.net>,
	network dev <netdev@vger.kernel.org>,
	linux-kernel@vger.kernel.org, tgraf@suug.ch,
	fengguang.wu@intel.com, wfg@linux.intel.com, lkp@01.org
Subject: Re: rhashtable: Prevent spurious EBUSY errors on insertion
Date: Fri, 18 Dec 2015 16:18:38 +0800	[thread overview]
Message-ID: <CADvbK_cArD4QjPzHC1W4ZY=e5dur=uJsQd9WwSB2yYhnq_YbOg@mail.gmail.com> (raw)
In-Reply-To: <20151218022654.GA18495@gondor.apana.org.au>

On Fri, Dec 18, 2015 at 10:26 AM, Herbert Xu
<herbert@gondor.apana.org.au> wrote:
> On Fri, Dec 18, 2015 at 12:07:08AM +0800, Xin Long wrote:
>>
>> I'm just wondering, why do not we handle the genuine double rehash
>> issue inside rhashtable? i mean it's just a temporary error that a
>> simple retry may fix it.
>
> Because a double rehash means that someone has cracked your hash
> function and there is no point in trying anymore.

ok, get your point, is it possible to be triggered by some cases under
a big stress insertion, but they are all legal cases. like we use rhash in
nftables, if there are a big batch sets to insert, may this issue happen?

>
> Cheers,
> --
> Email: Herbert Xu <herbert@gondor.apana.org.au>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

  reply	other threads:[~2015-12-18  8:18 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-20 17:17 [PATCH v2 0/4] improve fault-tolerance of rhashtable runtime-test Phil Sutter
2015-11-20 17:17 ` [PATCH v2 1/4] rhashtable-test: add cond_resched() to thread test Phil Sutter
2015-11-20 17:17 ` [PATCH v2 2/4] rhashtable-test: retry insert operations Phil Sutter
2015-11-20 17:17 ` [PATCH v2 3/4] rhashtable-test: calculate max_entries value by default Phil Sutter
2015-11-20 17:17 ` [PATCH v2 4/4] rhashtable-test: allow to retry even if -ENOMEM was returned Phil Sutter
2015-11-20 17:28   ` Phil Sutter
2015-11-23 17:38 ` [PATCH v2 0/4] improve fault-tolerance of rhashtable runtime-test David Miller
2015-11-30  9:37 ` Herbert Xu
2015-11-30 10:14   ` Phil Sutter
2015-11-30 10:18     ` Herbert Xu
2015-12-03 12:41       ` rhashtable: Prevent spurious EBUSY errors on insertion Herbert Xu
2015-12-03 15:38         ` Phil Sutter
2015-12-04 19:38         ` David Miller
2015-12-17  8:46         ` Xin Long
2015-12-17  8:48           ` Herbert Xu
2015-12-17  9:00             ` Xin Long
2015-12-17 16:07               ` Xin Long
2015-12-18  2:26                 ` Herbert Xu
2015-12-18  8:18                   ` Xin Long [this message]
2015-12-17 17:00               ` David Miller
2015-12-03 12:51       ` rhashtable: ENOMEM errors when hit with a flood of insertions Herbert Xu
2015-12-03 15:08         ` David Laight
2015-12-03 16:08         ` Eric Dumazet
2015-12-04  0:07           ` Herbert Xu
2015-12-04 14:39           ` rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation Herbert Xu
2015-12-04 17:01             ` Phil Sutter
2015-12-04 17:45               ` Eric Dumazet
2015-12-04 18:15                 ` Phil Sutter
2015-12-05  7:06                   ` Herbert Xu
2015-12-07 15:35                     ` Thomas Graf
2015-12-07 19:29                       ` David Miller
2015-12-09  2:18                     ` Thomas Graf
2015-12-09  2:24                       ` Herbert Xu
2015-12-09  2:36                         ` Thomas Graf
2015-12-09  2:38                           ` Herbert Xu
2015-12-09  2:42                             ` Thomas Graf
2015-12-04 21:53             ` David Miller
2015-12-05  7:03               ` Herbert Xu
2015-12-06  3:48                 ` David Miller

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