* [PATCH v3 1/2] Documentation: kdump: remind user of nr_cpus
@ 2016-08-03 0:59 ` Zhou Wenjian
0 siblings, 0 replies; 16+ messages in thread
From: Zhou Wenjian @ 2016-08-03 0:59 UTC (permalink / raw)
To: linux-kernel; +Cc: dyoung, d.hatayama, kexec, bhe
v2->v3: add description of nr_cpus.
v1->v2: change nr_cpus to maxcpus
nr_cpus can help to save memory. So we should remind user of it.
Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
---
Documentation/kdump/kdump.txt | 2 ++
1 file changed, 2 insertions(+)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 88ff63d..4aa194e 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -393,6 +393,8 @@ Notes on loading the dump-capture kernel:
* We generally don' have to bring up a SMP kernel just to capture the
dump. Hence generally it is useful either to build a UP dump-capture
kernel or specify maxcpus=1 option while loading dump-capture kernel.
+ Note, though maxcpus always works, we should replace it by nr_cpus to
+ save memory if supported by the current ARCH, such as x86.
* For s390x there are two kdump modes: If a ELF header is specified with
the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
--
1.8.3.1
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
2016-08-03 0:59 ` Zhou Wenjian
@ 2016-08-03 0:59 ` Zhou Wenjian
-1 siblings, 0 replies; 16+ messages in thread
From: Zhou Wenjian @ 2016-08-03 0:59 UTC (permalink / raw)
To: linux-kernel; +Cc: kexec, bhe, dyoung, d.hatayama
SMP dump-capture kernel is useful to improve the performance of kdump in
some cases. So add the description of bringing up SMP dump-capture kernel.
Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
---
Documentation/kdump/kdump.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 4aa194e..948b42d 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
Note, though maxcpus always works, we should replace it by nr_cpus to
save memory if supported by the current ARCH, such as x86.
+* We should bring up a SMP dump-capture kernel if we intend to use
+ multi-threads programs with it, such as parallel dump feature of
+ makedumpfile. Otherwise, the multi-threads program may have a great
+ performance degradation. To bring up a SMP dump-capture kernel, we
+ should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
+ loading it.
+
* For s390x there are two kdump modes: If a ELF header is specified with
the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
is done on all other architectures. If no elfcorehdr= kernel parameter is
--
1.8.3.1
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
@ 2016-08-03 0:59 ` Zhou Wenjian
0 siblings, 0 replies; 16+ messages in thread
From: Zhou Wenjian @ 2016-08-03 0:59 UTC (permalink / raw)
To: linux-kernel; +Cc: dyoung, d.hatayama, kexec, bhe
SMP dump-capture kernel is useful to improve the performance of kdump in
some cases. So add the description of bringing up SMP dump-capture kernel.
Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
---
Documentation/kdump/kdump.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 4aa194e..948b42d 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
Note, though maxcpus always works, we should replace it by nr_cpus to
save memory if supported by the current ARCH, such as x86.
+* We should bring up a SMP dump-capture kernel if we intend to use
+ multi-threads programs with it, such as parallel dump feature of
+ makedumpfile. Otherwise, the multi-threads program may have a great
+ performance degradation. To bring up a SMP dump-capture kernel, we
+ should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
+ loading it.
+
* For s390x there are two kdump modes: If a ELF header is specified with
the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
is done on all other architectures. If no elfcorehdr= kernel parameter is
--
1.8.3.1
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply related [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
2016-08-03 0:59 ` Zhou Wenjian
@ 2016-08-03 1:58 ` Baoquan He
-1 siblings, 0 replies; 16+ messages in thread
From: Baoquan He @ 2016-08-03 1:58 UTC (permalink / raw)
To: Zhou Wenjian; +Cc: linux-kernel, dyoung, d.hatayama, kexec
On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> SMP dump-capture kernel is useful to improve the performance of kdump in
> some cases. So add the description of bringing up SMP dump-capture kernel.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> ---
> Documentation/kdump/kdump.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 4aa194e..948b42d 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
> Note, though maxcpus always works, we should replace it by nr_cpus to
> save memory if supported by the current ARCH, such as x86.
>
> +* We should bring up a SMP dump-capture kernel if we intend to use
Well, here about SMP dump-capture kernel do you mean kdump kernel with
multi-cpu? If I understand it correctly, it's still SMP kdump kernel
though nr_cpus=1 is specified.
> + multi-threads programs with it, such as parallel dump feature of
> + makedumpfile. Otherwise, the multi-threads program may have a great
> + performance degradation. To bring up a SMP dump-capture kernel, we
> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
> + loading it.
> +
> * For s390x there are two kdump modes: If a ELF header is specified with
> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
> is done on all other architectures. If no elfcorehdr= kernel parameter is
> --
> 1.8.3.1
>
>
>
>
> _______________________________________________
> kexec mailing list
> kexec@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
@ 2016-08-03 1:58 ` Baoquan He
0 siblings, 0 replies; 16+ messages in thread
From: Baoquan He @ 2016-08-03 1:58 UTC (permalink / raw)
To: Zhou Wenjian; +Cc: kexec, d.hatayama, dyoung, linux-kernel
On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> SMP dump-capture kernel is useful to improve the performance of kdump in
> some cases. So add the description of bringing up SMP dump-capture kernel.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> ---
> Documentation/kdump/kdump.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 4aa194e..948b42d 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
> Note, though maxcpus always works, we should replace it by nr_cpus to
> save memory if supported by the current ARCH, such as x86.
>
> +* We should bring up a SMP dump-capture kernel if we intend to use
Well, here about SMP dump-capture kernel do you mean kdump kernel with
multi-cpu? If I understand it correctly, it's still SMP kdump kernel
though nr_cpus=1 is specified.
> + multi-threads programs with it, such as parallel dump feature of
> + makedumpfile. Otherwise, the multi-threads program may have a great
> + performance degradation. To bring up a SMP dump-capture kernel, we
> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
> + loading it.
> +
> * For s390x there are two kdump modes: If a ELF header is specified with
> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
> is done on all other architectures. If no elfcorehdr= kernel parameter is
> --
> 1.8.3.1
>
>
>
>
> _______________________________________________
> 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
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
2016-08-03 1:58 ` Baoquan He
@ 2016-08-03 2:05 ` "Zhou, Wenjian/周文剑"
-1 siblings, 0 replies; 16+ messages in thread
From: "Zhou, Wenjian/周文剑" @ 2016-08-03 2:05 UTC (permalink / raw)
To: Baoquan He; +Cc: linux-kernel, dyoung, d.hatayama, kexec
On 08/03/2016 09:58 AM, Baoquan He wrote:
> On 08/03/16 at 08:59am, Zhou Wenjian wrote:
>> SMP dump-capture kernel is useful to improve the performance of kdump in
>> some cases. So add the description of bringing up SMP dump-capture kernel.
>>
>> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
>> ---
>> Documentation/kdump/kdump.txt | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>> index 4aa194e..948b42d 100644
>> --- a/Documentation/kdump/kdump.txt
>> +++ b/Documentation/kdump/kdump.txt
>> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
>> Note, though maxcpus always works, we should replace it by nr_cpus to
>> save memory if supported by the current ARCH, such as x86.
>>
>> +* We should bring up a SMP dump-capture kernel if we intend to use
>
> Well, here about SMP dump-capture kernel do you mean kdump kernel with
> multi-cpu? If I understand it correctly, it's still SMP kdump kernel
> though nr_cpus=1 is specified.
>
Actually, I haven't know the detail about it. I wrote the sentence almost
based on the original description:
* We generally don' have to bring up a SMP kernel just to capture the
dump. Hence generally it is useful either to build a UP dump-capture
kernel or specify maxcpus=1 option while loading dump-capture kernel.
>> + multi-threads programs with it, such as parallel dump feature of
>> + makedumpfile. Otherwise, the multi-threads program may have a great
>> + performance degradation. To bring up a SMP dump-capture kernel, we
>> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
>> + loading it.
>> +
>> * For s390x there are two kdump modes: If a ELF header is specified with
>> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
>> is done on all other architectures. If no elfcorehdr= kernel parameter is
>> --
>> 1.8.3.1
>>
>>
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
>
>
--
Thanks
Zhou
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
@ 2016-08-03 2:05 ` "Zhou, Wenjian/周文剑"
0 siblings, 0 replies; 16+ messages in thread
From: "Zhou, Wenjian/周文剑" @ 2016-08-03 2:05 UTC (permalink / raw)
To: Baoquan He; +Cc: kexec, d.hatayama, dyoung, linux-kernel
On 08/03/2016 09:58 AM, Baoquan He wrote:
> On 08/03/16 at 08:59am, Zhou Wenjian wrote:
>> SMP dump-capture kernel is useful to improve the performance of kdump in
>> some cases. So add the description of bringing up SMP dump-capture kernel.
>>
>> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
>> ---
>> Documentation/kdump/kdump.txt | 7 +++++++
>> 1 file changed, 7 insertions(+)
>>
>> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>> index 4aa194e..948b42d 100644
>> --- a/Documentation/kdump/kdump.txt
>> +++ b/Documentation/kdump/kdump.txt
>> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
>> Note, though maxcpus always works, we should replace it by nr_cpus to
>> save memory if supported by the current ARCH, such as x86.
>>
>> +* We should bring up a SMP dump-capture kernel if we intend to use
>
> Well, here about SMP dump-capture kernel do you mean kdump kernel with
> multi-cpu? If I understand it correctly, it's still SMP kdump kernel
> though nr_cpus=1 is specified.
>
Actually, I haven't know the detail about it. I wrote the sentence almost
based on the original description:
* We generally don' have to bring up a SMP kernel just to capture the
dump. Hence generally it is useful either to build a UP dump-capture
kernel or specify maxcpus=1 option while loading dump-capture kernel.
>> + multi-threads programs with it, such as parallel dump feature of
>> + makedumpfile. Otherwise, the multi-threads program may have a great
>> + performance degradation. To bring up a SMP dump-capture kernel, we
>> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
>> + loading it.
>> +
>> * For s390x there are two kdump modes: If a ELF header is specified with
>> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
>> is done on all other architectures. If no elfcorehdr= kernel parameter is
>> --
>> 1.8.3.1
>>
>>
>>
>>
>> _______________________________________________
>> kexec mailing list
>> kexec@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/kexec
>
>
--
Thanks
Zhou
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
2016-08-03 2:05 ` "Zhou, Wenjian/周文剑"
@ 2016-08-03 2:18 ` Baoquan He
-1 siblings, 0 replies; 16+ messages in thread
From: Baoquan He @ 2016-08-03 2:18 UTC (permalink / raw)
To: "Zhou, Wenjian/周文剑"
Cc: linux-kernel, dyoung, d.hatayama, kexec
On 08/03/16 at 10:05am, "Zhou, Wenjian/周文剑" wrote:
> On 08/03/2016 09:58 AM, Baoquan He wrote:
> >On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> >>SMP dump-capture kernel is useful to improve the performance of kdump in
> >>some cases. So add the description of bringing up SMP dump-capture kernel.
> >>
> >>Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> >>---
> >> Documentation/kdump/kdump.txt | 7 +++++++
> >> 1 file changed, 7 insertions(+)
> >>
> >>diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> >>index 4aa194e..948b42d 100644
> >>--- a/Documentation/kdump/kdump.txt
> >>+++ b/Documentation/kdump/kdump.txt
> >>@@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
> >> Note, though maxcpus always works, we should replace it by nr_cpus to
> >> save memory if supported by the current ARCH, such as x86.
> >>
> >>+* We should bring up a SMP dump-capture kernel if we intend to use
> >
> >Well, here about SMP dump-capture kernel do you mean kdump kernel with
> >multi-cpu? If I understand it correctly, it's still SMP kdump kernel
> >though nr_cpus=1 is specified.
> >
>
> Actually, I haven't know the detail about it. I wrote the sentence almost
> based on the original description:
>
> * We generally don' have to bring up a SMP kernel just to capture the
> dump. Hence generally it is useful either to build a UP dump-capture
> kernel or specify maxcpus=1 option while loading dump-capture kernel.
This is right. Here it means either you build a UP kernel used for kdump
kernel because kdump kernel doesn't have to be the same as the 1st
kernel, or you use smp kernel with maxcpus=1 specified. So if you want
to say kdump kernel with multi-cpu need be brought up to improve the
performance of parallel dumping, you need point it out clearly.
>
> >>+ multi-threads programs with it, such as parallel dump feature of
> >>+ makedumpfile. Otherwise, the multi-threads program may have a great
> >>+ performance degradation. To bring up a SMP dump-capture kernel, we
> >>+ should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
> >>+ loading it.
> >>+
> >> * For s390x there are two kdump modes: If a ELF header is specified with
> >> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
> >> is done on all other architectures. If no elfcorehdr= kernel parameter is
> >>--
> >>1.8.3.1
> >>
> >>
> >>
> >>
> >>_______________________________________________
> >>kexec mailing list
> >>kexec@lists.infradead.org
> >>http://lists.infradead.org/mailman/listinfo/kexec
> >
> >
>
>
> --
> Thanks
> Zhou
>
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
@ 2016-08-03 2:18 ` Baoquan He
0 siblings, 0 replies; 16+ messages in thread
From: Baoquan He @ 2016-08-03 2:18 UTC (permalink / raw)
To: "Zhou, Wenjian/周文剑"
Cc: kexec, d.hatayama, dyoung, linux-kernel
On 08/03/16 at 10:05am, "Zhou, Wenjian/周文剑" wrote:
> On 08/03/2016 09:58 AM, Baoquan He wrote:
> >On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> >>SMP dump-capture kernel is useful to improve the performance of kdump in
> >>some cases. So add the description of bringing up SMP dump-capture kernel.
> >>
> >>Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> >>---
> >> Documentation/kdump/kdump.txt | 7 +++++++
> >> 1 file changed, 7 insertions(+)
> >>
> >>diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> >>index 4aa194e..948b42d 100644
> >>--- a/Documentation/kdump/kdump.txt
> >>+++ b/Documentation/kdump/kdump.txt
> >>@@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
> >> Note, though maxcpus always works, we should replace it by nr_cpus to
> >> save memory if supported by the current ARCH, such as x86.
> >>
> >>+* We should bring up a SMP dump-capture kernel if we intend to use
> >
> >Well, here about SMP dump-capture kernel do you mean kdump kernel with
> >multi-cpu? If I understand it correctly, it's still SMP kdump kernel
> >though nr_cpus=1 is specified.
> >
>
> Actually, I haven't know the detail about it. I wrote the sentence almost
> based on the original description:
>
> * We generally don' have to bring up a SMP kernel just to capture the
> dump. Hence generally it is useful either to build a UP dump-capture
> kernel or specify maxcpus=1 option while loading dump-capture kernel.
This is right. Here it means either you build a UP kernel used for kdump
kernel because kdump kernel doesn't have to be the same as the 1st
kernel, or you use smp kernel with maxcpus=1 specified. So if you want
to say kdump kernel with multi-cpu need be brought up to improve the
performance of parallel dumping, you need point it out clearly.
>
> >>+ multi-threads programs with it, such as parallel dump feature of
> >>+ makedumpfile. Otherwise, the multi-threads program may have a great
> >>+ performance degradation. To bring up a SMP dump-capture kernel, we
> >>+ should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
> >>+ loading it.
> >>+
> >> * For s390x there are two kdump modes: If a ELF header is specified with
> >> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
> >> is done on all other architectures. If no elfcorehdr= kernel parameter is
> >>--
> >>1.8.3.1
> >>
> >>
> >>
> >>
> >>_______________________________________________
> >>kexec mailing list
> >>kexec@lists.infradead.org
> >>http://lists.infradead.org/mailman/listinfo/kexec
> >
> >
>
>
> --
> Thanks
> Zhou
>
>
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
2016-08-03 2:18 ` Baoquan He
@ 2016-08-03 2:19 ` "Zhou, Wenjian/周文剑"
-1 siblings, 0 replies; 16+ messages in thread
From: "Zhou, Wenjian/周文剑" @ 2016-08-03 2:19 UTC (permalink / raw)
To: Baoquan He; +Cc: linux-kernel, dyoung, d.hatayama, kexec
On 08/03/2016 10:18 AM, Baoquan He wrote:
> On 08/03/16 at 10:05am, "Zhou, Wenjian/周文剑" wrote:
>> On 08/03/2016 09:58 AM, Baoquan He wrote:
>>> On 08/03/16 at 08:59am, Zhou Wenjian wrote:
>>>> SMP dump-capture kernel is useful to improve the performance of kdump in
>>>> some cases. So add the description of bringing up SMP dump-capture kernel.
>>>>
>>>> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
>>>> ---
>>>> Documentation/kdump/kdump.txt | 7 +++++++
>>>> 1 file changed, 7 insertions(+)
>>>>
>>>> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>>>> index 4aa194e..948b42d 100644
>>>> --- a/Documentation/kdump/kdump.txt
>>>> +++ b/Documentation/kdump/kdump.txt
>>>> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
>>>> Note, though maxcpus always works, we should replace it by nr_cpus to
>>>> save memory if supported by the current ARCH, such as x86.
>>>>
>>>> +* We should bring up a SMP dump-capture kernel if we intend to use
>>>
>>> Well, here about SMP dump-capture kernel do you mean kdump kernel with
>>> multi-cpu? If I understand it correctly, it's still SMP kdump kernel
>>> though nr_cpus=1 is specified.
>>>
>>
>> Actually, I haven't know the detail about it. I wrote the sentence almost
>> based on the original description:
>>
>> * We generally don' have to bring up a SMP kernel just to capture the
>> dump. Hence generally it is useful either to build a UP dump-capture
>> kernel or specify maxcpus=1 option while loading dump-capture kernel.
>
> This is right. Here it means either you build a UP kernel used for kdump
> kernel because kdump kernel doesn't have to be the same as the 1st
> kernel, or you use smp kernel with maxcpus=1 specified. So if you want
> to say kdump kernel with multi-cpu need be brought up to improve the
> performance of parallel dumping, you need point it out clearly.
>
I see. I will update the patch.
>>
>>>> + multi-threads programs with it, such as parallel dump feature of
>>>> + makedumpfile. Otherwise, the multi-threads program may have a great
>>>> + performance degradation. To bring up a SMP dump-capture kernel, we
>>>> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
>>>> + loading it.
>>>> +
>>>> * For s390x there are two kdump modes: If a ELF header is specified with
>>>> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
>>>> is done on all other architectures. If no elfcorehdr= kernel parameter is
>>>> --
>>>> 1.8.3.1
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> kexec mailing list
>>>> kexec@lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/kexec
>>>
>>>
>>
>>
>> --
>> Thanks
>> Zhou
>>
>>
>
>
--
Thanks
Zhou
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel
@ 2016-08-03 2:19 ` "Zhou, Wenjian/周文剑"
0 siblings, 0 replies; 16+ messages in thread
From: "Zhou, Wenjian/周文剑" @ 2016-08-03 2:19 UTC (permalink / raw)
To: Baoquan He; +Cc: kexec, d.hatayama, dyoung, linux-kernel
On 08/03/2016 10:18 AM, Baoquan He wrote:
> On 08/03/16 at 10:05am, "Zhou, Wenjian/周文剑" wrote:
>> On 08/03/2016 09:58 AM, Baoquan He wrote:
>>> On 08/03/16 at 08:59am, Zhou Wenjian wrote:
>>>> SMP dump-capture kernel is useful to improve the performance of kdump in
>>>> some cases. So add the description of bringing up SMP dump-capture kernel.
>>>>
>>>> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
>>>> ---
>>>> Documentation/kdump/kdump.txt | 7 +++++++
>>>> 1 file changed, 7 insertions(+)
>>>>
>>>> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>>>> index 4aa194e..948b42d 100644
>>>> --- a/Documentation/kdump/kdump.txt
>>>> +++ b/Documentation/kdump/kdump.txt
>>>> @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel:
>>>> Note, though maxcpus always works, we should replace it by nr_cpus to
>>>> save memory if supported by the current ARCH, such as x86.
>>>>
>>>> +* We should bring up a SMP dump-capture kernel if we intend to use
>>>
>>> Well, here about SMP dump-capture kernel do you mean kdump kernel with
>>> multi-cpu? If I understand it correctly, it's still SMP kdump kernel
>>> though nr_cpus=1 is specified.
>>>
>>
>> Actually, I haven't know the detail about it. I wrote the sentence almost
>> based on the original description:
>>
>> * We generally don' have to bring up a SMP kernel just to capture the
>> dump. Hence generally it is useful either to build a UP dump-capture
>> kernel or specify maxcpus=1 option while loading dump-capture kernel.
>
> This is right. Here it means either you build a UP kernel used for kdump
> kernel because kdump kernel doesn't have to be the same as the 1st
> kernel, or you use smp kernel with maxcpus=1 specified. So if you want
> to say kdump kernel with multi-cpu need be brought up to improve the
> performance of parallel dumping, you need point it out clearly.
>
I see. I will update the patch.
>>
>>>> + multi-threads programs with it, such as parallel dump feature of
>>>> + makedumpfile. Otherwise, the multi-threads program may have a great
>>>> + performance degradation. To bring up a SMP dump-capture kernel, we
>>>> + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while
>>>> + loading it.
>>>> +
>>>> * For s390x there are two kdump modes: If a ELF header is specified with
>>>> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
>>>> is done on all other architectures. If no elfcorehdr= kernel parameter is
>>>> --
>>>> 1.8.3.1
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> kexec mailing list
>>>> kexec@lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/kexec
>>>
>>>
>>
>>
>> --
>> Thanks
>> Zhou
>>
>>
>
>
--
Thanks
Zhou
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^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-03 0:59 ` Zhou Wenjian
@ 2016-08-03 1:23 ` Baoquan He
-1 siblings, 0 replies; 16+ messages in thread
From: Baoquan He @ 2016-08-03 1:23 UTC (permalink / raw)
To: Zhou Wenjian, akpm; +Cc: linux-kernel, kexec, dyoung, d.hatayama
On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> v2->v3: add description of nr_cpus.
> v1->v2: change nr_cpus to maxcpus
>
> nr_cpus can help to save memory. So we should remind user of it.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> ---
> Documentation/kdump/kdump.txt | 2 ++
> 1 file changed, 2 insertions(+)
Looks good to me! Thanks, Wenjian.
Ack this series
Acked-by: Baoquan He <bhe@redhat.com>
Hi Andrew,
Could you please help merge this patchset?
Thanks
Baoquan
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 88ff63d..4aa194e 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -393,6 +393,8 @@ Notes on loading the dump-capture kernel:
> * We generally don' have to bring up a SMP kernel just to capture the
> dump. Hence generally it is useful either to build a UP dump-capture
> kernel or specify maxcpus=1 option while loading dump-capture kernel.
> + Note, though maxcpus always works, we should replace it by nr_cpus to
> + save memory if supported by the current ARCH, such as x86.
>
> * For s390x there are two kdump modes: If a ELF header is specified with
> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
> --
> 1.8.3.1
>
>
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 1/2] Documentation: kdump: remind user of nr_cpus
@ 2016-08-03 1:23 ` Baoquan He
0 siblings, 0 replies; 16+ messages in thread
From: Baoquan He @ 2016-08-03 1:23 UTC (permalink / raw)
To: Zhou Wenjian, akpm; +Cc: dyoung, d.hatayama, kexec, linux-kernel
On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> v2->v3: add description of nr_cpus.
> v1->v2: change nr_cpus to maxcpus
>
> nr_cpus can help to save memory. So we should remind user of it.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> ---
> Documentation/kdump/kdump.txt | 2 ++
> 1 file changed, 2 insertions(+)
Looks good to me! Thanks, Wenjian.
Ack this series
Acked-by: Baoquan He <bhe@redhat.com>
Hi Andrew,
Could you please help merge this patchset?
Thanks
Baoquan
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 88ff63d..4aa194e 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -393,6 +393,8 @@ Notes on loading the dump-capture kernel:
> * We generally don' have to bring up a SMP kernel just to capture the
> dump. Hence generally it is useful either to build a UP dump-capture
> kernel or specify maxcpus=1 option while loading dump-capture kernel.
> + Note, though maxcpus always works, we should replace it by nr_cpus to
> + save memory if supported by the current ARCH, such as x86.
>
> * For s390x there are two kdump modes: If a ELF header is specified with
> the elfcorehdr= kernel parameter, it is used by the kdump kernel as it
> --
> 1.8.3.1
>
>
>
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^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-03 0:59 ` Zhou Wenjian
@ 2016-08-08 2:14 ` Dave Young
-1 siblings, 0 replies; 16+ messages in thread
From: Dave Young @ 2016-08-08 2:14 UTC (permalink / raw)
To: Zhou Wenjian; +Cc: linux-kernel, d.hatayama, kexec, bhe
On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> v2->v3: add description of nr_cpus.
> v1->v2: change nr_cpus to maxcpus
>
> nr_cpus can help to save memory. So we should remind user of it.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> ---
> Documentation/kdump/kdump.txt | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 88ff63d..4aa194e 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -393,6 +393,8 @@ Notes on loading the dump-capture kernel:
> * We generally don' have to bring up a SMP kernel just to capture the
> dump. Hence generally it is useful either to build a UP dump-capture
> kernel or specify maxcpus=1 option while loading dump-capture kernel.
> + Note, though maxcpus always works, we should replace it by nr_cpus to
> + save memory if supported by the current ARCH, such as x86.
Can you replace "we" with "you" in both these patches?
Thanks
Dave
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH v3 1/2] Documentation: kdump: remind user of nr_cpus
@ 2016-08-08 2:14 ` Dave Young
0 siblings, 0 replies; 16+ messages in thread
From: Dave Young @ 2016-08-08 2:14 UTC (permalink / raw)
To: Zhou Wenjian; +Cc: d.hatayama, kexec, linux-kernel, bhe
On 08/03/16 at 08:59am, Zhou Wenjian wrote:
> v2->v3: add description of nr_cpus.
> v1->v2: change nr_cpus to maxcpus
>
> nr_cpus can help to save memory. So we should remind user of it.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
> ---
> Documentation/kdump/kdump.txt | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 88ff63d..4aa194e 100644
> --- a/Documentation/kdump/kdump.txt
> +++ b/Documentation/kdump/kdump.txt
> @@ -393,6 +393,8 @@ Notes on loading the dump-capture kernel:
> * We generally don' have to bring up a SMP kernel just to capture the
> dump. Hence generally it is useful either to build a UP dump-capture
> kernel or specify maxcpus=1 option while loading dump-capture kernel.
> + Note, though maxcpus always works, we should replace it by nr_cpus to
> + save memory if supported by the current ARCH, such as x86.
Can you replace "we" with "you" in both these patches?
Thanks
Dave
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