* [PATCH v4 1/2] Documentation: kdump: remind user of nr_cpus
@ 2016-08-03 2:31 ` Zhou Wenjian
0 siblings, 0 replies; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-03 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: kexec, bhe, dyoung, d.hatayama
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
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..b474060 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 related [flat|nested] 6+ messages in thread
* [PATCH v4 1/2] Documentation: kdump: remind user of nr_cpus
@ 2016-08-03 2:31 ` Zhou Wenjian
0 siblings, 0 replies; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-03 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: dyoung, d.hatayama, kexec, bhe
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
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..b474060 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] 6+ messages in thread
* [PATCH v4 2/2] Documentation: kdump: add description of enable multi-cpus support
2016-08-03 2:31 ` Zhou Wenjian
@ 2016-08-03 2:31 ` Zhou Wenjian
-1 siblings, 0 replies; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-03 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: kexec, bhe, dyoung, d.hatayama
multi-cpus support is useful to improve the performance of kdump in
some cases. So add the description of enable multi-cpus support in
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 b474060..028cf26 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 enable multi-cpus support in 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 enable multi-cpus support, we should bring up
+ a SMP dump-capture kernel and specify maxcpus\nr_cpus, 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] 6+ messages in thread
* [PATCH v4 2/2] Documentation: kdump: add description of enable multi-cpus support
@ 2016-08-03 2:31 ` Zhou Wenjian
0 siblings, 0 replies; 6+ messages in thread
From: Zhou Wenjian @ 2016-08-03 2:31 UTC (permalink / raw)
To: linux-kernel; +Cc: dyoung, d.hatayama, kexec, bhe
multi-cpus support is useful to improve the performance of kdump in
some cases. So add the description of enable multi-cpus support in
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 b474060..028cf26 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 enable multi-cpus support in 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 enable multi-cpus support, we should bring up
+ a SMP dump-capture kernel and specify maxcpus\nr_cpus, 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] 6+ messages in thread
* Re: [PATCH v4 1/2] Documentation: kdump: remind user of nr_cpus
2016-08-03 2:31 ` Zhou Wenjian
@ 2016-08-03 3:01 ` Baoquan He
-1 siblings, 0 replies; 6+ messages in thread
From: Baoquan He @ 2016-08-03 3:01 UTC (permalink / raw)
To: Zhou Wenjian, akpm; +Cc: linux-kernel, dyoung, d.hatayama, kexec
Hi Wenjian,
On 08/03/16 at 10:31am, Zhou Wenjian wrote:
> 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
>
> nr_cpus can help to save memory. So we should remind user of it.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
The change log can be put in cover-letter if you are posting a patchset,
or put it below the three dashes where it will be discarded
automatically when maintainer apply your patch to his/her branch.
Next time please CC akpm too, he helps to pick up these kexec related
patches.
Except for this, I am fine with this patchset. Ack it again.
Acked-by: Baoquan He <bhe@redhat.com>
Thanks
Baoquan
> ---
> Documentation/kdump/kdump.txt | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 88ff63d..b474060 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 [flat|nested] 6+ messages in thread
* Re: [PATCH v4 1/2] Documentation: kdump: remind user of nr_cpus
@ 2016-08-03 3:01 ` Baoquan He
0 siblings, 0 replies; 6+ messages in thread
From: Baoquan He @ 2016-08-03 3:01 UTC (permalink / raw)
To: Zhou Wenjian, akpm; +Cc: kexec, d.hatayama, dyoung, linux-kernel
Hi Wenjian,
On 08/03/16 at 10:31am, Zhou Wenjian wrote:
> 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
>
> nr_cpus can help to save memory. So we should remind user of it.
>
> Signed-off-by: Zhou Wenjian <zhouwj-fnst@cn.fujitsu.com>
The change log can be put in cover-letter if you are posting a patchset,
or put it below the three dashes where it will be discarded
automatically when maintainer apply your patch to his/her branch.
Next time please CC akpm too, he helps to pick up these kexec related
patches.
Except for this, I am fine with this patchset. Ack it again.
Acked-by: Baoquan He <bhe@redhat.com>
Thanks
Baoquan
> ---
> Documentation/kdump/kdump.txt | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt
> index 88ff63d..b474060 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
_______________________________________________
kexec mailing list
kexec@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/kexec
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2016-08-03 3:12 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-08-03 2:31 [PATCH v4 1/2] Documentation: kdump: remind user of nr_cpus Zhou Wenjian
2016-08-03 2:31 ` Zhou Wenjian
2016-08-03 2:31 ` [PATCH v4 2/2] Documentation: kdump: add description of enable multi-cpus support Zhou Wenjian
2016-08-03 2:31 ` Zhou Wenjian
2016-08-03 3:01 ` [PATCH v4 1/2] Documentation: kdump: remind user of nr_cpus Baoquan He
2016-08-03 3:01 ` Baoquan He
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