linux-kernel - Re: rhashtable: Use __vmalloc with GFP

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Message-ID: <20151209023844.GA24736@gondor.apana.org.au>
Date:	Wed, 9 Dec 2015 10:38:44 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	Thomas Graf <tgraf@...g.ch>
Cc:	David Miller <davem@...emloft.net>, Phil Sutter <phil@....cc>,
	Eric Dumazet <eric.dumazet@...il.com>, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, fengguang.wu@...el.com,
	wfg@...ux.intel.com, lkp@...org
Subject: Re: rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation

On Wed, Dec 09, 2015 at 03:36:32AM +0100, Thomas Graf wrote:
> 
> Without knowing your exact implementation plans: introducing an
> additional reference indirection for every lookup will have a
> huge performance penalty as well.
> 
> Is your plan to only introduce the master table after an
> allocation has failed?

Right, obviously the extra indirections would only come into play
after a failed allocation.  As soon as we can run the worker thread
it'll try to remove the extra indirections by doing vmalloc.

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