From: Thomas Graf <tgraf@suug.ch>
To: Patrick McHardy <kaber@trash.net>
Cc: davem@davemloft.net, netdev@vger.kernel.org,
kernel@vger.kernel.org, herbert@gondor.apana.org.au,
paulmck@linux.vnet.ibm.com, edumazet@google.com,
john.r.fastabend@intel.com, josh@joshtriplett.org,
netfilter-devel@vger.kernel.org
Subject: Re: [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking
Date: Fri, 16 Jan 2015 16:15:30 +0000 [thread overview]
Message-ID: <20150116161530.GC15052@casper.infradead.org> (raw)
In-Reply-To: <20150116160354.GI30132@acer.localdomain>
On 01/16/15 at 04:03pm, Patrick McHardy wrote:
> On 16.01, Thomas Graf wrote:
> > A walker may not see insertions that occur after the walker was started
> > if resizing is enabled. Is that a problem for nftables?
>
> No, that would be Ok. The case I'm wondering about is:
>
> - insertion
> - resize starts
> - another insertion
> - walker, resize not finished yet
Correct, walker may not see "another insertion". The window for this
behavior to occur is not the full resize operation, just the linking
period, but it may occur. The length of the window is typically
equal to a grace period.
We can provide a synchronization function to block the dumper or the
insertion/removal until the linking is complete. The latter would
give the old runtime behaviour back (variable runtime of insert),
the blocked dumper might be preferred. What do you think?
next prev parent reply other threads:[~2015-01-16 16:15 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <cover.1418647641.git.tgraf@suug.ch>
2014-12-15 12:51 ` [PATCH 1/9] rhashtable: Do hashing inside of rhashtable_lookup_compare() Thomas Graf
2014-12-15 12:51 ` [PATCH 5/9] nft_hash: Remove rhashtable_remove_pprev() Thomas Graf
2014-12-15 12:51 ` [PATCH 7/9] rhashtable: Per bucket locks & deferred expansion/shrinking Thomas Graf
2015-01-16 15:34 ` Patrick McHardy
2015-01-16 15:58 ` Thomas Graf
2015-01-16 16:03 ` Patrick McHardy
2015-01-16 16:15 ` Thomas Graf [this message]
2015-01-16 16:32 ` Patrick McHardy
2015-01-16 16:38 ` Thomas Graf
2015-01-16 16:51 ` Patrick McHardy
2015-01-16 16:43 ` David Laight
2015-01-16 16:53 ` Thomas Graf
2015-01-16 18:36 ` Patrick McHardy
2015-01-16 19:18 ` Thomas Graf
2015-01-16 19:35 ` Patrick McHardy
2015-01-16 20:46 ` Pablo Neira Ayuso
2015-01-16 20:53 ` Patrick McHardy
2015-01-19 9:01 ` Paul E. McKenney
2015-01-21 5:23 ` Herbert Xu
2015-01-21 5:29 ` Paul E. McKenney
2015-01-21 5:30 ` Herbert Xu
2015-01-21 5:36 ` Paul E. McKenney
2015-01-16 20:49 ` Herbert Xu
2015-01-16 21:31 ` Patrick McHardy
2015-01-17 0:33 ` Herbert Xu
2015-01-17 8:06 ` Patrick McHardy
2015-01-17 9:32 ` Herbert Xu
2015-01-17 9:51 ` Patrick McHardy
2015-01-17 10:13 ` Herbert Xu
2015-01-17 11:56 ` Patrick McHardy
2015-01-16 21:36 ` Thomas Graf
2015-01-16 22:07 ` Patrick McHardy
2015-01-16 23:34 ` Thomas Graf
2015-01-17 8:02 ` Patrick McHardy
2015-01-19 12:58 ` Thomas Graf
2015-01-19 9:45 ` David Laight
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