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

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Message-ID: <20151209022454.GA24515@gondor.apana.org.au>
Date:	Wed, 9 Dec 2015 10:24:54 +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 03:18:26AM +0100, Thomas Graf wrote:
> 
> Assuming that we only encounter this scenario with very large
> table sizes, it might be OK to assume that deferring the actual
> resize via the worker thread while continuing to insert above
> 100% utilization in atomic context is safe.

As test_rhashtable has demonstrated already this approach doesn't
work.  There is nothing in the kernel that will ensure that the
worker thread gets to run at all.

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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