From: David Hildenbrand <david@redhat.com>
To: Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Russell King <linux@armlinux.org.uk>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Vasily Gorbik <gor@linux.ibm.com>, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
linux-mm@kvack.org, linux-s390@vger.kernel.org
Subject: Re: [RFC/RFT PATCH 1/5] s390: make crashk_res resource a child of "System RAM"
Date: Tue, 1 Jun 2021 11:02:17 +0200 [thread overview]
Message-ID: <f6cd0c41-d7e2-65f5-94eb-9a21514df799@redhat.com> (raw)
In-Reply-To: <1efc386c-2cb4-164f-7194-497f142f969f@redhat.com>
On 01.06.21 10:45, David Hildenbrand wrote:
> On 31.05.21 14:29, Mike Rapoport wrote:
>> From: Mike Rapoport <rppt@linux.ibm.com>
>>
>> Commit 4e042af463f8 ("s390/kexec: fix crash on resize of reserved memory")
>> added a comment that says "crash kernel resource should not be part of the
>> System RAM resource" but never explained why. As it looks from the code in
>> the kernel and in kexec there is no actual reason for that.
>
> Are you sure?
>
> Looking at kexec-tools: kexec/arch/s390/kexec-s390.c
>
> get_memory_ranges_s390() wants "System RAM" and Crash kernel only with
> "with_crashk=1". Your patch would change that. "Crash kernel" would
> always be included if you make it a child of "System RAM".
>
> Further, get_memory_ranges() and is_crashkernel_mem_reserved() look out
> for "Crash kernel\n" via parse_iomem_single().
>
> However, parse_iomem_single() does not care about ranges that start with
> spaces IIRC via
> sscanf(line, "%llx-%llx : %n" ...
I think I'm wrong about that one because I read
"Input white-space characters (as specified by the isspace function) are
skipped, unless the specification includes a [ , c , or n specifier"
So having it as a child won't affect parse_iomem_single().
--
Thanks,
David / dhildenb
WARNING: multiple messages have this Message-ID (diff)
From: David Hildenbrand <david@redhat.com>
To: Mike Rapoport <rppt@kernel.org>, linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Russell King <linux@armlinux.org.uk>,
Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Vasily Gorbik <gor@linux.ibm.com>, Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org,
linux-mm@kvack.org, linux-s390@vger.kernel.org
Subject: Re: [RFC/RFT PATCH 1/5] s390: make crashk_res resource a child of "System RAM"
Date: Tue, 1 Jun 2021 11:02:17 +0200 [thread overview]
Message-ID: <f6cd0c41-d7e2-65f5-94eb-9a21514df799@redhat.com> (raw)
In-Reply-To: <1efc386c-2cb4-164f-7194-497f142f969f@redhat.com>
On 01.06.21 10:45, David Hildenbrand wrote:
> On 31.05.21 14:29, Mike Rapoport wrote:
>> From: Mike Rapoport <rppt@linux.ibm.com>
>>
>> Commit 4e042af463f8 ("s390/kexec: fix crash on resize of reserved memory")
>> added a comment that says "crash kernel resource should not be part of the
>> System RAM resource" but never explained why. As it looks from the code in
>> the kernel and in kexec there is no actual reason for that.
>
> Are you sure?
>
> Looking at kexec-tools: kexec/arch/s390/kexec-s390.c
>
> get_memory_ranges_s390() wants "System RAM" and Crash kernel only with
> "with_crashk=1". Your patch would change that. "Crash kernel" would
> always be included if you make it a child of "System RAM".
>
> Further, get_memory_ranges() and is_crashkernel_mem_reserved() look out
> for "Crash kernel\n" via parse_iomem_single().
>
> However, parse_iomem_single() does not care about ranges that start with
> spaces IIRC via
> sscanf(line, "%llx-%llx : %n" ...
I think I'm wrong about that one because I read
"Input white-space characters (as specified by the isspace function) are
skipped, unless the specification includes a [ , c , or n specifier"
So having it as a child won't affect parse_iomem_single().
--
Thanks,
David / dhildenb
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next prev parent reply other threads:[~2021-06-01 9:02 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-31 12:29 [RFC/RFT PATCH 0/5] consolidate "System RAM" resources setup Mike Rapoport
2021-05-31 12:29 ` Mike Rapoport
2021-05-31 12:29 ` [RFC/RFT PATCH 1/5] s390: make crashk_res resource a child of "System RAM" Mike Rapoport
2021-05-31 12:29 ` Mike Rapoport
2021-06-01 8:45 ` David Hildenbrand
2021-06-01 8:45 ` David Hildenbrand
2021-06-01 9:02 ` David Hildenbrand [this message]
2021-06-01 9:02 ` David Hildenbrand
2021-06-02 6:25 ` Mike Rapoport
2021-06-02 6:25 ` Mike Rapoport
2021-06-01 13:18 ` Gerald Schaefer
2021-06-01 13:18 ` Gerald Schaefer
2021-06-02 6:54 ` Mike Rapoport
2021-06-02 6:54 ` Mike Rapoport
2021-05-31 12:29 ` [RFC/RFT PATCH 2/5] memblock: introduce generic memblock_setup_resources() Mike Rapoport
2021-05-31 12:29 ` Mike Rapoport
2021-06-01 13:54 ` Russell King (Oracle)
2021-06-01 13:54 ` Russell King (Oracle)
2021-06-02 8:33 ` Mike Rapoport
2021-06-02 8:33 ` Mike Rapoport
2021-06-02 10:15 ` Russell King (Oracle)
2021-06-02 10:15 ` Russell King (Oracle)
2021-06-02 13:54 ` Mike Rapoport
2021-06-02 13:54 ` Mike Rapoport
2021-06-02 15:51 ` Russell King (Oracle)
2021-06-02 15:51 ` Russell King (Oracle)
2021-06-02 18:43 ` Mike Rapoport
2021-06-02 18:43 ` Mike Rapoport
2021-06-02 20:15 ` Russell King (Oracle)
2021-06-02 20:15 ` Russell King (Oracle)
2021-06-03 10:32 ` Mike Rapoport
2021-06-03 10:32 ` Mike Rapoport
2021-05-31 12:29 ` [RFC/RFT PATCH 3/5] arm: switch to " Mike Rapoport
2021-05-31 12:29 ` Mike Rapoport
2021-05-31 12:29 ` [RFC/RFT PATCH 4/5] MIPS: switch to generic memblock_setup_resources Mike Rapoport
2021-05-31 12:29 ` Mike Rapoport
2021-05-31 12:29 ` [RFC/RFT PATCH 5/5] arm64: switch to generic memblock_setup_resources() Mike Rapoport
2021-05-31 12:29 ` Mike Rapoport
2021-06-01 13:44 ` [RFC/RFT PATCH 0/5] consolidate "System RAM" resources setup Russell King (Oracle)
2021-06-01 13:44 ` Russell King (Oracle)
2021-06-02 7:05 ` Mike Rapoport
2021-06-02 7:05 ` Mike Rapoport
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