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From: Xunlei Pang <xpang@redhat.com>
To: Dave Young <dyoung@redhat.com>, Xunlei Pang <xlpang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>,
	x86@kernel.org, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	Robert LeBlanc <robert@leblancnet.us>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2] x86/crash: Update the stale comment in reserve_crashkernel()
Date: Mon, 23 Jan 2017 21:24:22 +0800	[thread overview]
Message-ID: <58860406.1030604@redhat.com> (raw)
In-Reply-To: <20170123084850.GA15988@dhcp-128-65.nay.redhat.com>

On 01/23/2017 at 04:48 PM, Dave Young wrote:
> Hi, Xunlei
>
> On 01/23/17 at 02:48pm, Xunlei Pang wrote:
>> CRASH_KERNEL_ADDR_MAX has been missing for a long time,
>> update it with more detailed explanation.
>>
>> Cc: Robert LeBlanc <robert@leblancnet.us>
>> Cc: Baoquan He <bhe@redhat.com>
>> Signed-off-by: Xunlei Pang <xlpang@redhat.com>
>> ---
>>  arch/x86/kernel/setup.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>> index 4cfba94..c32a167 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -575,7 +575,9 @@ static void __init reserve_crashkernel(void)
>>  	/* 0 means: find the address automatically */
>>  	if (crash_base <= 0) {
>>  		/*
>> -		 *  kexec want bzImage is below CRASH_KERNEL_ADDR_MAX
>> +		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory
>> +		 * as old kexec-tools loads bzImage below that, unless
>> +		 * "crashkernel=size[KMG],high" is specified.
> There is already comment before the define of those macros, also
> there are 32bit case which has a different reason about 512M there as
> well.

If we see from the kexec's perspective, we have a common CRASH_ADDR_LOW_MAX
definition for both x86 32-bit and 64-bit(32-bit x86 has the same value defined for
CRASH_ADDR_LOW_MAX and CRASH_ADDR_HIGH_MAX), so old kexec will load below
CRASH_ADDR_LOW_MAX,  so I think the description is fine :-)

Regards,
Xunlei

>
> So it looks better to just drop the one line comment without adding
> further comments here.
>>  		 */
>>  		crash_base = memblock_find_in_range(CRASH_ALIGN,
>>  						    high ? CRASH_ADDR_HIGH_MAX
>> -- 
>> 1.8.3.1
>>
> Thanks
> Dave
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec


_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec

WARNING: multiple messages have this Message-ID (diff)
From: Xunlei Pang <xpang@redhat.com>
To: Dave Young <dyoung@redhat.com>, Xunlei Pang <xlpang@redhat.com>
Cc: Baoquan He <bhe@redhat.com>,
	x86@kernel.org, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
	Borislav Petkov <bp@alien8.de>, "H. Peter Anvin" <hpa@zytor.com>,
	Robert LeBlanc <robert@leblancnet.us>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v2] x86/crash: Update the stale comment in reserve_crashkernel()
Date: Mon, 23 Jan 2017 21:24:22 +0800	[thread overview]
Message-ID: <58860406.1030604@redhat.com> (raw)
In-Reply-To: <20170123084850.GA15988@dhcp-128-65.nay.redhat.com>

On 01/23/2017 at 04:48 PM, Dave Young wrote:
> Hi, Xunlei
>
> On 01/23/17 at 02:48pm, Xunlei Pang wrote:
>> CRASH_KERNEL_ADDR_MAX has been missing for a long time,
>> update it with more detailed explanation.
>>
>> Cc: Robert LeBlanc <robert@leblancnet.us>
>> Cc: Baoquan He <bhe@redhat.com>
>> Signed-off-by: Xunlei Pang <xlpang@redhat.com>
>> ---
>>  arch/x86/kernel/setup.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
>> index 4cfba94..c32a167 100644
>> --- a/arch/x86/kernel/setup.c
>> +++ b/arch/x86/kernel/setup.c
>> @@ -575,7 +575,9 @@ static void __init reserve_crashkernel(void)
>>  	/* 0 means: find the address automatically */
>>  	if (crash_base <= 0) {
>>  		/*
>> -		 *  kexec want bzImage is below CRASH_KERNEL_ADDR_MAX
>> +		 * Set CRASH_ADDR_LOW_MAX upper bound for crash memory
>> +		 * as old kexec-tools loads bzImage below that, unless
>> +		 * "crashkernel=size[KMG],high" is specified.
> There is already comment before the define of those macros, also
> there are 32bit case which has a different reason about 512M there as
> well.

If we see from the kexec's perspective, we have a common CRASH_ADDR_LOW_MAX
definition for both x86 32-bit and 64-bit(32-bit x86 has the same value defined for
CRASH_ADDR_LOW_MAX and CRASH_ADDR_HIGH_MAX), so old kexec will load below
CRASH_ADDR_LOW_MAX,  so I think the description is fine :-)

Regards,
Xunlei

>
> So it looks better to just drop the one line comment without adding
> further comments here.
>>  		 */
>>  		crash_base = memblock_find_in_range(CRASH_ALIGN,
>>  						    high ? CRASH_ADDR_HIGH_MAX
>> -- 
>> 1.8.3.1
>>
> Thanks
> Dave
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec

  reply	other threads:[~2017-01-23 13:23 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-01-23  6:48 [PATCH v2] x86/crash: Update the stale comment in reserve_crashkernel() Xunlei Pang
2017-01-23  6:48 ` Xunlei Pang
2017-01-23  8:01 ` [tip:x86/debug] " tip-bot for Xunlei Pang
2017-01-23  8:48 ` [PATCH v2] " Dave Young
2017-01-23  8:48   ` Dave Young
2017-01-23 13:24   ` Xunlei Pang [this message]
2017-01-23 13:24     ` Xunlei Pang

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