From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Hollis Blanchard <hollisb@us.ibm.com>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] powerpc: remove WARN_ON() from dma-noncoherent.c
Date: Tue, 11 Nov 2008 13:09:04 +1100 [thread overview]
Message-ID: <1226369344.7530.51.camel@pasglop> (raw)
In-Reply-To: <2094bb9371fc6b6c228b.1226363616@localhost.localdomain>
On Mon, 2008-11-10 at 18:33 -0600, Hollis Blanchard wrote:
> I can't tell why this WARN_ON exists, and there's no comment explaining it.
> Whether the pmd is present or not, pte_alloc_kernel() seems to handle both
> cases.
>
> Booting a 440 kernel with 64K PAGE_SIZE triggers the warning, but boot
> successfully completes and I see no problems beyond that.
>
> Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>
I can't see any reason neither off hand, so
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Ben.
> ---
>
> Large page support is critical for improving KVM performance, so I'd like this
> apparently unnecessary warning to be removed to make way for Ilya's patch.
>
> Vitaly, this code was added by you in Feb 2007. Any thoughts?
>
> diff --git a/arch/powerpc/lib/dma-noncoherent.c b/arch/powerpc/lib/dma-noncoherent.c
> --- a/arch/powerpc/lib/dma-noncoherent.c
> +++ b/arch/powerpc/lib/dma-noncoherent.c
> @@ -320,7 +320,6 @@ static int __init dma_alloc_init(void)
> ret = -ENOMEM;
> break;
> }
> - WARN_ON(!pmd_none(*pmd));
>
> pte = pte_alloc_kernel(pmd, CONSISTENT_BASE);
> if (!pte) {
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
prev parent reply other threads:[~2008-11-11 2:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-11 0:33 [PATCH] powerpc: remove WARN_ON() from dma-noncoherent.c Hollis Blanchard
2008-11-11 2:09 ` Benjamin Herrenschmidt [this message]
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