* [PATCH v8 0/2] update the doc of kdump
@ 2016-08-18 2:31 Zhou Wenjian
2016-08-18 2:31 ` [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus Zhou Wenjian
2016-08-18 2:31 ` [PATCH v8 2/2] Documentation: kdump: add description of enable multi-cpus support Zhou Wenjian
0 siblings, 2 replies; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-18 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: akpm, dyoung, bhe, vgoyal, corbet, kexec, linux-doc, xlpang
v7->v8: fix "a SMP kernel" to "an SMP kernel" and replace "\" with "/"
v6->v7: fix typo
v5->v6: replace "we" with "you"
v4->v5: move change log to cover letter
v3->v4: update the description of bring up SMP dump-capture kernel
v2->v3: add description of nr_cpus.
v1->v2: change nr_cpus to maxcpus
Zhou Wenjian (2):
Documentation: kdump: remind user of nr_cpus
Documentation: kdump: add description of enable multi-cpus support
Documentation/kdump/kdump.txt | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
--
1.8.3.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-18 2:31 [PATCH v8 0/2] update the doc of kdump Zhou Wenjian
@ 2016-08-18 2:31 ` Zhou Wenjian
2016-08-18 2:36 ` Joe Perches
2016-08-18 2:31 ` [PATCH v8 2/2] Documentation: kdump: add description of enable multi-cpus support Zhou Wenjian
1 sibling, 1 reply; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-18 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: akpm, dyoung, bhe, vgoyal, corbet, kexec, linux-doc, xlpang
nr_cpus can help to save memory. So we should remind user of it.
Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Xunlei Pang <xpang@redhat.com>
---
Documentation/kdump/kdump.txt | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index 88ff63d..e8da1d5 100644
--- a/Documentation/kdump/kdump.txt
+++ b/Documentation/kdump/kdump.txt
@@ -390,9 +390,11 @@ Notes on loading the dump-capture kernel:
* Boot parameter "1" boots the dump-capture kernel into single-user
mode without networking. If you want networking, use "3".
-* We generally don' have to bring up a SMP kernel just to capture the
+* We generally don' have to bring up an 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, you 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 related [flat|nested] 6+ messages in thread
* [PATCH v8 2/2] Documentation: kdump: add description of enable multi-cpus support
2016-08-18 2:31 [PATCH v8 0/2] update the doc of kdump Zhou Wenjian
2016-08-18 2:31 ` [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus Zhou Wenjian
@ 2016-08-18 2:31 ` Zhou Wenjian
1 sibling, 0 replies; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-18 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: akpm, dyoung, bhe, vgoyal, corbet, kexec, linux-doc, xlpang
multi-cpu support is useful to improve the performance of kdump in
some cases. So add the description of enable multi-cpu support in
dump-capture kernel.
Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
Acked-by: Baoquan He <bhe@redhat.com>
Acked-by: Xunlei Pang <xpang@redhat.com>
---
Documentation/kdump/kdump.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
index e8da1d5..c781d49 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, you should replace it by nr_cpus to
save memory if supported by the current ARCH, such as x86.
+* You should enable multi-cpu support in dump-capture kernel if you intend
+ to use multi-thread programs with it, such as parallel dump feature of
+ makedumpfile. Otherwise, the multi-thread program may have a great
+ performance degradation. To enable multi-cpu support, you should bring up an
+ SMP dump-capture kernel and specify maxcpus/nr_cpus, disable_cpu_apicid=[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] 6+ messages in thread
* Re: [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-18 2:31 ` [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus Zhou Wenjian
@ 2016-08-18 2:36 ` Joe Perches
2016-08-18 6:47 ` Dave Young
0 siblings, 1 reply; 6+ messages in thread
From: Joe Perches @ 2016-08-18 2:36 UTC (permalink / raw)
To: Zhou Wenjian, linux-kernel
Cc: akpm, dyoung, bhe, vgoyal, corbet, kexec, linux-doc, xlpang
On Thu, 2016-08-18 at 10:31 +0800, Zhou Wenjian wrote:
> nr_cpus can help to save memory. So we should remind user of it.
trivia:
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
[]
> @@ -390,9 +390,11 @@ Notes on loading the dump-capture kernel:
> * Boot parameter "1" boots the dump-capture kernel into single-user
> mode without networking. If you want networking, use "3".
>
> -* We generally don' have to bring up a SMP kernel just to capture the
> +* We generally don' have to bring up an SMP kernel just to capture the
don't or do not
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-18 2:36 ` Joe Perches
@ 2016-08-18 6:47 ` Dave Young
2016-08-18 7:12 ` "Zhou, Wenjian/周文剑"
0 siblings, 1 reply; 6+ messages in thread
From: Dave Young @ 2016-08-18 6:47 UTC (permalink / raw)
To: Joe Perches
Cc: Zhou Wenjian, linux-kernel, akpm, bhe, vgoyal, corbet, kexec,
linux-doc, xlpang
On 08/17/16 at 07:36pm, Joe Perches wrote:
> On Thu, 2016-08-18 at 10:31 +0800, Zhou Wenjian wrote:
> > nr_cpus can help to save memory. So we should remind user of it.
>
> trivia:
> > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> []
> > @@ -390,9 +390,11 @@ Notes on loading the dump-capture kernel:
> > * Boot parameter "1" boots the dump-capture kernel into single-user
> > mode without networking. If you want networking, use "3".
> >
> > -* We generally don' have to bring up a SMP kernel just to capture the
> > +* We generally don' have to bring up an SMP kernel just to capture the
>
> don't or do not
>
Use do not is better, also need replace 'We' with 'You' to be
consistent with other part.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-18 6:47 ` Dave Young
@ 2016-08-18 7:12 ` "Zhou, Wenjian/周文剑"
0 siblings, 0 replies; 6+ messages in thread
From: "Zhou, Wenjian/周文剑" @ 2016-08-18 7:12 UTC (permalink / raw)
To: Dave Young, Joe Perches
Cc: linux-kernel, akpm, bhe, vgoyal, corbet, kexec, linux-doc, xlpang
On 08/18/2016 02:47 PM, Dave Young wrote:
> On 08/17/16 at 07:36pm, Joe Perches wrote:
>> On Thu, 2016-08-18 at 10:31 +0800, Zhou Wenjian wrote:
>>> nr_cpus can help to save memory. So we should remind user of it.
>>
>> trivia:
>>> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
>> []
>>> @@ -390,9 +390,11 @@ Notes on loading the dump-capture kernel:
>>> * Boot parameter "1" boots the dump-capture kernel into single-user
>>> mode without networking. If you want networking, use "3".
>>>
>>> -* We generally don' have to bring up a SMP kernel just to capture the
>>> +* We generally don' have to bring up an SMP kernel just to capture the
>>
>> don't or do not
>>
>
> Use do not is better, also need replace 'We' with 'You' to be
> consistent with other part.
>
>
I think it's better to fix it in another patch,
for it doesn't have much relevance to the patch set.
I'll post it alone later.
--
Thanks
Zhou
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-08-18 7:14 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2016-08-18 2:31 [PATCH v8 0/2] update the doc of kdump Zhou Wenjian
2016-08-18 2:31 ` [PATCH v8 1/2] Documentation: kdump: remind user of nr_cpus Zhou Wenjian
2016-08-18 2:36 ` Joe Perches
2016-08-18 6:47 ` Dave Young
2016-08-18 7:12 ` "Zhou, Wenjian/周文剑"
2016-08-18 2:31 ` [PATCH v8 2/2] Documentation: kdump: add description of enable multi-cpus support Zhou Wenjian
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