powerpc/crashkernel: take mem option into account
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Message ID 1568001906-5750-1-git-send-email-kernelfans@gmail.com
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  • powerpc/crashkernel: take mem option into account
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Commit Message

Pingfan Liu Sept. 9, 2019, 4:05 a.m. UTC
'mem=" option is an easy way to put high pressure on memory during some
test. Hence in stead of total mem, the effective usable memory size should
be considered when reserving mem for crashkernel. Otherwise the boot up may
experience oom issue.

E.g passing
crashkernel="2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G", and
mem=5G.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
To: linuxppc-dev@lists.ozlabs.org
---
 arch/powerpc/kernel/machine_kexec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Pingfan Liu Sept. 9, 2019, 7:35 a.m. UTC | #1
On Mon, Sep 9, 2019 at 12:05 PM Pingfan Liu <kernelfans@gmail.com> wrote:
>
> 'mem=" option is an easy way to put high pressure on memory during some
> test. Hence in stead of total mem, the effective usable memory size should
> be considered when reserving mem for crashkernel. Otherwise the boot up may
> experience oom issue.
>
> E.g passing
> crashkernel="2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G", and
> mem=5G.
>
> Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
> Cc: Hari Bathini <hbathini@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> To: linuxppc-dev@lists.ozlabs.org
> ---
>  arch/powerpc/kernel/machine_kexec.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
> index c4ed328..714b733 100644
> --- a/arch/powerpc/kernel/machine_kexec.c
> +++ b/arch/powerpc/kernel/machine_kexec.c
> @@ -114,11 +114,12 @@ void machine_kexec(struct kimage *image)
>
>  void __init reserve_crashkernel(void)
>  {
> -       unsigned long long crash_size, crash_base;
> +       unsigned long long crash_size, crash_base, total_mem_sz;
>         int ret;
>
> +       total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size();
Here memory_limit is used to esstimation and may be changed.
So I think it is better to use memory_limit here than moving
memblock_enforce_memory_limit() before the call to
reserve_crashkernel()

Thanks,
Pingfan
>         /* use common parsing */
> -       ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
> +       ret = parse_crashkernel(boot_command_line, total_mem_sz,
>                         &crash_size, &crash_base);
>         if (ret == 0 && crash_size > 0) {
>                 crashk_res.start = crash_base;
> --
> 2.7.5
>
Pingfan Liu Sept. 12, 2019, 2:50 a.m. UTC | #2
NACK it. Due to a miss the updating of printk info. I will send out V2

On Mon, Sep 9, 2019 at 12:05 PM Pingfan Liu <kernelfans@gmail.com> wrote:
>
> 'mem=" option is an easy way to put high pressure on memory during some
> test. Hence in stead of total mem, the effective usable memory size should
> be considered when reserving mem for crashkernel. Otherwise the boot up may
> experience oom issue.
>
> E.g passing
> crashkernel="2G-4G:384M,4G-16G:512M,16G-64G:1G,64G-128G:2G,128G-:4G", and
> mem=5G.
>
> Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
> Cc: Hari Bathini <hbathini@linux.ibm.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> To: linuxppc-dev@lists.ozlabs.org
> ---
>  arch/powerpc/kernel/machine_kexec.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
> index c4ed328..714b733 100644
> --- a/arch/powerpc/kernel/machine_kexec.c
> +++ b/arch/powerpc/kernel/machine_kexec.c
> @@ -114,11 +114,12 @@ void machine_kexec(struct kimage *image)
>
>  void __init reserve_crashkernel(void)
>  {
> -       unsigned long long crash_size, crash_base;
> +       unsigned long long crash_size, crash_base, total_mem_sz;
>         int ret;
>
> +       total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size();
>         /* use common parsing */
> -       ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
> +       ret = parse_crashkernel(boot_command_line, total_mem_sz,
>                         &crash_size, &crash_base);
>         if (ret == 0 && crash_size > 0) {
>                 crashk_res.start = crash_base;
> --
> 2.7.5
>

Patch
diff mbox series

diff --git a/arch/powerpc/kernel/machine_kexec.c b/arch/powerpc/kernel/machine_kexec.c
index c4ed328..714b733 100644
--- a/arch/powerpc/kernel/machine_kexec.c
+++ b/arch/powerpc/kernel/machine_kexec.c
@@ -114,11 +114,12 @@  void machine_kexec(struct kimage *image)
 
 void __init reserve_crashkernel(void)
 {
-	unsigned long long crash_size, crash_base;
+	unsigned long long crash_size, crash_base, total_mem_sz;
 	int ret;
 
+	total_mem_sz = memory_limit ? memory_limit : memblock_phys_mem_size();
 	/* use common parsing */
-	ret = parse_crashkernel(boot_command_line, memblock_phys_mem_size(),
+	ret = parse_crashkernel(boot_command_line, total_mem_sz,
 			&crash_size, &crash_base);
 	if (ret == 0 && crash_size > 0) {
 		crashk_res.start = crash_base;