Re: [PATCH 0/3 v3] Fix kdump failures with crashkernel=high

From: Borislav Petkov <bp@alien8.de>
To: Joerg Roedel <joro@8bytes.org>, "H. Peter Anvin" <hpa@zytor.com>,
	Ingo Molnar <mingo@redhat.com>
Cc: jroedel@suse.de, Baoquan He <bhe@redhat.com>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	x86@kernel.org, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Dave Young <dyoung@redhat.com>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH 0/3 v3] Fix kdump failures with crashkernel=high
Date: Fri, 5 Jun 2015 15:27:36 +0200	[thread overview]
Message-ID: <20150605132736.GF3679@pd.tnic> (raw)
In-Reply-To: <1433500202-25531-1-git-send-email-joro@8bytes.org>

On Fri, Jun 05, 2015 at 12:29:59PM +0200, Joerg Roedel wrote:
> v2->v3
> 
> * Rebased to v4.1-rc6
> * Updated changelogs as requested and added outcome of
>   previous discussions
> * Added more Acked-bys
> 
> v1->v2:
> 
> * Updated comments based on feedback from Konrad
> * Added Acked-bys
> * Rebased to v3.19-rc3
> 
> Hi,
> 
> here is a patch-set to fix failed kdump kernel boots when
> the systems was booted with crashkernel=X,high. On those
> systems the kernel allocates only 72MiB of low-memory for
> DMA buffers, which showed to be too low on some systems.
> 
> The problem is that 64MiB of the low-memory is allocated by
> swiotlb, leaving 8MB for the page-allocator. But swiotlb
> tries to allocate DMA memory from the page-allocator first,
> which fails pretty fast in the boot sequence, causing
> warnings. This patch-set removes these warnings.
> 
> But even the 64MiB for swiotlb are eaten up on some systems,
> so that the default of low-memory allocated for the
> crash-kernel is increase from 72MB to 256MB (only changing
> the defaults, can still be overwritten by crashkernel=X,low).
> 
> This number comes from experiments on the affected systems,
> 128MiB low-memory was still not enough there, thus I set the
> value to 256MiB to fix the issues.
> 
> Any feedback appreciated.
> 
> Thanks,
> 
> 	Joerg
> 
> Joerg Roedel (3):
>   swiotlb: Warn on allocation failure in swiotlb_alloc_coherent
>   x86, swiotlb: Try coherent allocations with __GFP_NOWARN
>   x86, crash: Allocate enough low-mem when crashkernel=high
> 
>  arch/x86/kernel/pci-swiotlb.c |  7 +++++++
>  arch/x86/kernel/setup.c       |  5 ++++-
>  lib/swiotlb.c                 | 11 +++++++++--
>  3 files changed, 20 insertions(+), 3 deletions(-)

Looks simple enough, all applied, thanks.

hpa, Ingo, any concerns?

-- 
Regards/Gruss,
    Boris.

ECO tip #101: Trim your mails when you reply.
--

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