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From: Herbert Xu <herbert@gondor.apana.org.au>
To: Tom Herbert <tom@quantonium.net>
Cc: davem@davemloft.net, netdev@vger.kernel.org, rohit@quantonium.net
Subject: Re: [PATCH net-next 1/5] rhashtable: Don't reset walker table in rhashtable_walk_start
Date: Sat, 2 Dec 2017 09:18:09 +1100	[thread overview]
Message-ID: <20171201221809.GA6972@gondor.apana.org.au> (raw)
In-Reply-To: <20171201000305.2392-2-tom@quantonium.net>

On Thu, Nov 30, 2017 at 04:03:01PM -0800, Tom Herbert wrote:
> Remove the code that resets the walker table. The walker table should
> only be initialized in the walk init function or when a future table is
> encountered. If the walker table is NULL this is the indication that
> the walk has completed and this information can be used to break a
> multi-call walk in the table (e.g. successive calls to nelink_dump
> that are dumping elements of an rhashtable).
> 
> This also allows us to change rhashtable_walk_start to return void
> since the only error it was returning was -EAGAIN for a table change.
> This patch changes all the callers of rhashtable_walk_start to expect
> void which eliminates logic needed to check the return value for a
> rare condition. Note that -EAGAIN will be returned in a call
> to rhashtable_walk_next which seems to always follow the start
> of the walk so there should be no behavioral change in doing this.
> 
> Signed-off-by: Tom Herbert <tom@quantonium.net>

Doesn't this mean that if a walk encounters a rehash you may end up
missing half or more of the hash table?

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:[~2017-12-01 22:18 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-01  0:03 [PATCH net-next 0/5] rhashtable: New features in walk and bucket locks Tom Herbert
2017-12-01  0:03 ` [PATCH net-next 1/5] rhashtable: Don't reset walker table in rhashtable_walk_start Tom Herbert
2017-12-01 22:18   ` Herbert Xu [this message]
2017-12-01 23:29     ` Tom Herbert
2017-12-02  1:07       ` Tom Herbert
2017-12-01  0:03 ` [PATCH net-next 2/5] rhashtable: Add rhastable_walk_peek Tom Herbert
2017-12-01  0:38   ` Herbert Xu
2017-12-01  1:15     ` Tom Herbert
2017-12-01  1:21       ` Herbert Xu
2017-12-01  3:50         ` Tom Herbert
2017-12-01  0:03 ` [PATCH net-next 3/5] rhashtable: abstract out function to get hash Tom Herbert
2017-12-01  0:03 ` [PATCH net-next 4/5] spinlock: Add library function to allocate spinlock buckets array Tom Herbert
2017-12-01  0:03 ` [PATCH net-next 5/5] rhashtable: Call library function alloc_bucket_locks Tom Herbert

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