From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Young <dyoung@redhat.com>, Baoquan He <bhe@redhat.com>,
Vivek Goyal <vgoyal@redhat.com>, <kexec@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, Will Deacon <will@kernel.org>,
<linux-arm-kernel@lists.infradead.org>,
Jonathan Corbet <corbet@lwn.net>, <linux-doc@vger.kernel.org>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Randy Dunlap <rdunlap@infradead.org>,
Feng Zhou <zhoufeng.zf@bytedance.com>,
Kefeng Wang <wangkefeng.wang@huawei.com>,
Chen Zhou <dingguo.cz@antgroup.com>,
John Donnelly <John.p.donnelly@oracle.com>,
"Dave Kleikamp" <dave.kleikamp@oracle.com>
Subject: Re: [PATCH v3 2/2] arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones
Date: Tue, 8 Nov 2022 10:06:38 +0800 [thread overview]
Message-ID: <6b20a203-6aab-2b87-9b95-814aeb79b5bd@huawei.com> (raw)
In-Reply-To: <Y2k8yuUghrbQE6da@arm.com>
On 2022/11/8 1:13, Catalin Marinas wrote:
> On Mon, Jul 11, 2022 at 05:03:19PM +0800, Zhen Lei wrote:
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 5390f361208ccf7..8539598f9e58b4d 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -138,6 +138,7 @@ static void __init reserve_crashkernel(void)
>> unsigned long long crash_max = CRASH_ADDR_LOW_MAX;
>> char *cmdline = boot_command_line;
>> int ret;
>> + bool fixed_base;
>>
>> if (!IS_ENABLED(CONFIG_KEXEC_CORE))
>> return;
>> @@ -166,15 +167,28 @@ static void __init reserve_crashkernel(void)
>> return;
>> }
>>
>> + fixed_base = !!crash_base;
>> crash_size = PAGE_ALIGN(crash_size);
>>
>> /* User specifies base address explicitly. */
>> - if (crash_base)
>> + if (fixed_base)
>> crash_max = crash_base + crash_size;
>
> Not a fan of '!!', it is converted automatically. If you don't like the
> conversion, just initialise fixed_base to false and here:
>
> if (crash_base) {
> fixed_base = true;
OK, This way would be better.
> crash_max = crash_base + crash_size;
> }
>
>> +retry:
>> crash_base = memblock_phys_alloc_range(crash_size, CRASH_ALIGN,
>> crash_base, crash_max);
>> if (!crash_base) {
>> + /*
>> + * Attempt to fully allocate low memory failed, fall back
>> + * to high memory, the minimum required low memory will be
>> + * reserved later.
>> + */
>
> I'm not sure this comment makes sense. If !crash_base, it doesn't mean
> the kernel failed to fully allocate low memory. crash_max here could be
> CRASH_ADDR_HIGH_MAX if crashkerne=X,high was specified. Maybe says
> something like "If the first attempt was for low memory, fall back to
> high ..."
This description is accurate. I'll update. Thanks.
>
>> + if (!fixed_base && (crash_max == CRASH_ADDR_LOW_MAX)) {
>> + crash_max = CRASH_ADDR_HIGH_MAX;
>> + crash_low_size = DEFAULT_CRASH_KERNEL_LOW_SIZE;
>> + goto retry;
>> + }
>
> The retry logic looks fine, it only happens once as crash_max is
> updated.
>
--
Regards,
Zhen Lei
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next prev parent reply other threads:[~2022-11-08 2:08 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-11 9:03 [PATCH v3 0/2] arm64: kdump: Function supplement and performance optimization Zhen Lei
2022-07-11 9:03 ` [PATCH v3 1/2] arm64: kdump: Provide default size when crashkernel=Y,low is not specified Zhen Lei
2022-08-02 8:37 ` Will Deacon
2022-08-02 10:12 ` Leizhen (ThunderTown)
2022-08-02 12:46 ` Baoquan He
2022-11-07 14:07 ` Catalin Marinas
2022-11-16 11:50 ` Leizhen (ThunderTown)
2022-11-07 17:18 ` Catalin Marinas
2022-11-08 2:47 ` Leizhen (ThunderTown)
2022-07-11 9:03 ` [PATCH v3 2/2] arm64: kdump: Support crashkernel=X fall back to reserve region above DMA zones Zhen Lei
2022-11-07 17:13 ` Catalin Marinas
2022-11-08 2:06 ` Leizhen (ThunderTown) [this message]
2022-08-01 8:20 ` [PATCH v3 0/2] arm64: kdump: Function supplement and performance optimization Baoquan He
2022-08-02 2:47 ` Leizhen (ThunderTown)
2022-10-06 14:55 ` john.p.donnelly
2022-10-13 10:46 ` Baoquan He
2022-10-14 16:25 ` John Donnelly
2022-10-14 16:29 ` Catalin Marinas
2022-10-26 19:41 ` john.p.donnelly
2022-11-15 11:58 ` Will Deacon
2022-11-15 12:18 ` Leizhen (ThunderTown)
2022-11-15 13:30 ` Catalin Marinas
2022-11-15 13:40 ` Leizhen (ThunderTown)
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