From: Baoquan He <bhe@redhat.com>
To: Huacai Chen <chenhuacai@loongson.cn>, akpm@linux-foundation.org
Cc: Vivek Goyal <vgoyal@redhat.com>, Dave Young <dyoung@redhat.com>,
Youling Tang <tangyouling@kylinos.cn>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kdump: Defer the insertion of crashkernel resources
Date: Fri, 5 Jan 2024 10:53:01 +0800 [thread overview]
Message-ID: <ZZdvDYg6sk8P2JWn@MiWiFi-R3L-srv> (raw)
In-Reply-To: <20231229080213.2622204-1-chenhuacai@loongson.cn>
Huacai,
On 12/29/23 at 04:02pm, Huacai Chen wrote:
> In /proc/iomem, sub-regions should be inserted after their parent,
> otherwise the insertion of parent resource fails. But after generic
> crashkernel reservation applied, in both RISC-V and ARM64 (LoongArch
> will also use generic reservation later on), crashkernel resources are
> inserted before their parent, which causes the parent disappear in
> /proc/iomem. So we defer the insertion of crashkernel resources to an
> early_initcall().
>
> 1, Without 'crashkernel' parameter:
>
> 100d0100-100d01ff : LOON0001:00
> 100d0100-100d01ff : LOON0001:00 LOON0001:00
> 100e0000-100e0bff : LOON0002:00
> 100e0000-100e0bff : LOON0002:00 LOON0002:00
> 1fe001e0-1fe001e7 : serial
> 90400000-fa17ffff : System RAM
> f6220000-f622ffff : Reserved
> f9ee0000-f9ee3fff : Reserved
> fa120000-fa17ffff : Reserved
> fa190000-fe0bffff : System RAM
> fa190000-fa1bffff : Reserved
> fe4e0000-47fffffff : System RAM
> 43c000000-441ffffff : Reserved
> 47ff98000-47ffa3fff : Reserved
> 47ffa4000-47ffa7fff : Reserved
> 47ffa8000-47ffabfff : Reserved
> 47ffac000-47ffaffff : Reserved
> 47ffb0000-47ffb3fff : Reserved
>
> 2, With 'crashkernel' parameter, before this patch:
>
> 100d0100-100d01ff : LOON0001:00
> 100d0100-100d01ff : LOON0001:00 LOON0001:00
> 100e0000-100e0bff : LOON0002:00
> 100e0000-100e0bff : LOON0002:00 LOON0002:00
> 1fe001e0-1fe001e7 : serial
> e6200000-f61fffff : Crash kernel
> fa190000-fe0bffff : System RAM
> fa190000-fa1bffff : Reserved
> fe4e0000-47fffffff : System RAM
> 43c000000-441ffffff : Reserved
> 47ff98000-47ffa3fff : Reserved
> 47ffa4000-47ffa7fff : Reserved
> 47ffa8000-47ffabfff : Reserved
> 47ffac000-47ffaffff : Reserved
> 47ffb0000-47ffb3fff : Reserved
>
> 3, With 'crashkernel' parameter, after this patch:
>
> 100d0100-100d01ff : LOON0001:00
> 100d0100-100d01ff : LOON0001:00 LOON0001:00
> 100e0000-100e0bff : LOON0002:00
> 100e0000-100e0bff : LOON0002:00 LOON0002:00
> 1fe001e0-1fe001e7 : serial
> 90400000-fa17ffff : System RAM
> e6200000-f61fffff : Crash kernel
> f6220000-f622ffff : Reserved
> f9ee0000-f9ee3fff : Reserved
> fa120000-fa17ffff : Reserved
> fa190000-fe0bffff : System RAM
> fa190000-fa1bffff : Reserved
> fe4e0000-47fffffff : System RAM
> 43c000000-441ffffff : Reserved
> 47ff98000-47ffa3fff : Reserved
> 47ffa4000-47ffa7fff : Reserved
> 47ffa8000-47ffabfff : Reserved
> 47ffac000-47ffaffff : Reserved
> 47ffb0000-47ffb3fff : Reserved
This looks like a great catch. I am curious where arm64 and loongarch
insert the system RAM range into iomem before crashk_res and
crashk_low_res. On x86, it should be done by pci or acpi init which is
earlier than crashkernel parsing and inserting into iomem, just went\
through codes, haven't adding debugging code to print.
>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
> kernel/crash_core.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index d4313b53837e..755d8d4ef5b0 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -377,7 +377,6 @@ static int __init reserve_crashkernel_low(unsigned long long low_size)
>
> crashk_low_res.start = low_base;
> crashk_low_res.end = low_base + low_size - 1;
> - insert_resource(&iomem_resource, &crashk_low_res);
> #endif
> return 0;
> }
> @@ -459,8 +458,19 @@ void __init reserve_crashkernel_generic(char *cmdline,
>
> crashk_res.start = crash_base;
> crashk_res.end = crash_base + crash_size - 1;
> - insert_resource(&iomem_resource, &crashk_res);
> }
> +
> +static __init int insert_crashkernel_resources(void)
> +{
> + if (crashk_res.start < crashk_res.end)
> + insert_resource(&iomem_resource, &crashk_res);
> +
> + if (crashk_low_res.start < crashk_low_res.end)
> + insert_resource(&iomem_resource, &crashk_low_res);
> +
> + return 0;
> +}
> +early_initcall(insert_crashkernel_resources);
> #endif
>
> int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
> --
> 2.39.3
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
>
next prev parent reply other threads:[~2024-01-05 2:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-29 8:02 [PATCH] kdump: Defer the insertion of crashkernel resources Huacai Chen
2024-01-05 2:53 ` Baoquan He [this message]
2024-01-05 16:49 ` Andrew Morton
2024-01-06 2:09 ` Baoquan He
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZZdvDYg6sk8P2JWn@MiWiFi-R3L-srv \
--to=bhe@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=chenhuacai@loongson.cn \
--cc=dyoung@redhat.com \
--cc=kexec@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=tangyouling@kylinos.cn \
--cc=vgoyal@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox