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From: chenzhou <chenzhou10@huawei.com>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	<catalin.marinas@arm.com>, <will@kernel.org>
Cc: song.bao.hua@hisilicon.com, xiexiuqi@huawei.com,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, huawei.libin@huawei.com,
	akpm@linux-foundation.org, ardb@kernel.org, rppt@kernel.org
Subject: Re: [PATCH 2/2] arm64: mm: fix kdump broken with ZONE_DMA reintroduced
Date: Mon, 28 Dec 2020 15:32:35 +0800	[thread overview]
Message-ID: <deeb19d6-29e2-f76e-9e28-6ad77c7cb1fa@huawei.com> (raw)
In-Reply-To: <653d43ed326e6a3974660c0ca2ad8a847a4ff986.camel@suse.de>

Hi Nicolas,

Thanks for your review.


On 2020/12/26 18:34, Nicolas Saenz Julienne wrote:
> Hi Chen, thanks for looking at this.
>
> On Sat, 2020-12-26 at 11:35 +0800, Chen Zhou wrote:
>> If the memory reserved for crash dump kernel falled in ZONE_DMA32,
>> the devices in crash dump kernel need to use ZONE_DMA will alloc fail.
>>
>> Fix this by reserving low memory in ZONE_DMA if CONFIG_ZONE_DMA is
>> enabled, otherwise, reserving in ZONE_DMA32.
>>
>> Fixes: bff3b04460a8 ("arm64: mm: reserve CMA and crashkernel in ZONE_DMA32")
> I'm not so sure this counts as a fix, if someone backports it it'll probably
> break things as it depends on the series that dynamically sizes DMA zones.
I write this just because kdump is broken from this commit.
>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
> Why not doing the same with CMA? You'll probably have to move the
> dma_contiguous_reserve() call into bootmem_init() so as to make sure that
> arm64_dma_phys_limit is populated.
You are right, CMA also need this. I will do this in next version.

Thanks,
Chen Zhou
>
> Regards,
> Nicolas
>
>>  arch/arm64/mm/init.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 7b9809e39927..5074e945f1a6 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -85,7 +85,8 @@ static void __init reserve_crashkernel(void)
>>  
>>
>>  	if (crash_base == 0) {
>>  		/* Current arm64 boot protocol requires 2MB alignment */
>> -		crash_base = memblock_find_in_range(0, arm64_dma32_phys_limit,
>> +		crash_base = memblock_find_in_range(0,
>> +				arm64_dma_phys_limit ? : arm64_dma32_phys_limit,
>>  				crash_size, SZ_2M);
>>  		if (crash_base == 0) {
>>  			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
>


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WARNING: multiple messages have this Message-ID (diff)
From: chenzhou <chenzhou10@huawei.com>
To: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>,
	<catalin.marinas@arm.com>, <will@kernel.org>
Cc: <ardb@kernel.org>, <akpm@linux-foundation.org>, <rppt@kernel.org>,
	<song.bao.hua@hisilicon.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <huawei.libin@huawei.com>,
	<xiexiuqi@huawei.com>
Subject: Re: [PATCH 2/2] arm64: mm: fix kdump broken with ZONE_DMA reintroduced
Date: Mon, 28 Dec 2020 15:32:35 +0800	[thread overview]
Message-ID: <deeb19d6-29e2-f76e-9e28-6ad77c7cb1fa@huawei.com> (raw)
In-Reply-To: <653d43ed326e6a3974660c0ca2ad8a847a4ff986.camel@suse.de>

Hi Nicolas,

Thanks for your review.


On 2020/12/26 18:34, Nicolas Saenz Julienne wrote:
> Hi Chen, thanks for looking at this.
>
> On Sat, 2020-12-26 at 11:35 +0800, Chen Zhou wrote:
>> If the memory reserved for crash dump kernel falled in ZONE_DMA32,
>> the devices in crash dump kernel need to use ZONE_DMA will alloc fail.
>>
>> Fix this by reserving low memory in ZONE_DMA if CONFIG_ZONE_DMA is
>> enabled, otherwise, reserving in ZONE_DMA32.
>>
>> Fixes: bff3b04460a8 ("arm64: mm: reserve CMA and crashkernel in ZONE_DMA32")
> I'm not so sure this counts as a fix, if someone backports it it'll probably
> break things as it depends on the series that dynamically sizes DMA zones.
I write this just because kdump is broken from this commit.
>
>> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
>> ---
> Why not doing the same with CMA? You'll probably have to move the
> dma_contiguous_reserve() call into bootmem_init() so as to make sure that
> arm64_dma_phys_limit is populated.
You are right, CMA also need this. I will do this in next version.

Thanks,
Chen Zhou
>
> Regards,
> Nicolas
>
>>  arch/arm64/mm/init.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 7b9809e39927..5074e945f1a6 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -85,7 +85,8 @@ static void __init reserve_crashkernel(void)
>>  
>>
>>  	if (crash_base == 0) {
>>  		/* Current arm64 boot protocol requires 2MB alignment */
>> -		crash_base = memblock_find_in_range(0, arm64_dma32_phys_limit,
>> +		crash_base = memblock_find_in_range(0,
>> +				arm64_dma_phys_limit ? : arm64_dma32_phys_limit,
>>  				crash_size, SZ_2M);
>>  		if (crash_base == 0) {
>>  			pr_warn("cannot allocate crashkernel (size:0x%llx)\n",
>


  reply	other threads:[~2020-12-28  7:35 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-26  3:35 [PATCH 0/2] arm64: mm: fix kdump broken with ZONE_DMA reintroduced Chen Zhou
2020-12-26  3:35 ` Chen Zhou
2020-12-26  3:35 ` [PATCH 1/2] arm64: mm: update the comments about ZONE_DMA Chen Zhou
2020-12-26  3:35   ` Chen Zhou
2020-12-26 10:35   ` Nicolas Saenz Julienne
2020-12-26 10:35     ` Nicolas Saenz Julienne
2020-12-26  3:35 ` [PATCH 2/2] arm64: mm: fix kdump broken with ZONE_DMA reintroduced Chen Zhou
2020-12-26  3:35   ` Chen Zhou
2020-12-26 10:34   ` Nicolas Saenz Julienne
2020-12-26 10:34     ` Nicolas Saenz Julienne
2020-12-28  7:32     ` chenzhou [this message]
2020-12-28  7:32       ` chenzhou
2021-01-07 18:34       ` Catalin Marinas
2021-01-07 18:34         ` Catalin Marinas
2021-01-07 14:25     ` Catalin Marinas
2021-01-07 14:25       ` Catalin Marinas
2021-01-08  1:09       ` chenzhou
2021-01-08  1:09         ` chenzhou
2021-01-20 12:40 ` [PATCH 0/2] " Will Deacon
2021-01-20 12:40   ` Will Deacon
2021-01-20 13:07   ` Catalin Marinas
2021-01-20 13:07     ` Catalin Marinas
2021-01-21  2:37     ` chenzhou
2021-01-21  2:37       ` chenzhou

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