* [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
@ 2020-07-15 2:54 Jingqi Liu
2020-07-24 7:15 ` Liu, Jingqi
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Jingqi Liu @ 2020-07-15 2:54 UTC (permalink / raw)
To: Paolo Bonzini, Xiao Guangrong, Dan Williams; +Cc: Jingqi Liu, qemu-devel
At the end of live migration, QEMU uses msync() to flush the data to
the backend storage. When the backend file is a character device dax,
the pages explicitly avoid the page cache. It will return failure from msync().
The following warning is output.
"warning: qemu_ram_msync: failed to sync memory range“
So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
-object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
---
docs/nvdimm.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
index c2c6e441b3..31048aff5e 100644
--- a/docs/nvdimm.txt
+++ b/docs/nvdimm.txt
@@ -243,6 +243,13 @@ use the QEMU command line:
-object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem=on
+At the end of live migration, QEMU uses msync() to flush the data to the
+backend storage. When the backend file is a character device dax, the pages
+explicitly avoid the page cache. It will return failure from msync().
+So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
+
+ -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
+
References
----------
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
2020-07-15 2:54 [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file Jingqi Liu
@ 2020-07-24 7:15 ` Liu, Jingqi
2020-07-28 1:09 ` Liu, Jingqi
2020-07-29 10:42 ` Stefan Hajnoczi
2 siblings, 0 replies; 7+ messages in thread
From: Liu, Jingqi @ 2020-07-24 7:15 UTC (permalink / raw)
To: Paolo Bonzini, Xiao Guangrong, Williams, Dan J; +Cc: qemu-devel
Ping for comments.
On 7/15/2020 10:54 AM, Liu, Jingqi wrote:
> At the end of live migration, QEMU uses msync() to flush the data to
> the backend storage. When the backend file is a character device dax,
> the pages explicitly avoid the page cache. It will return failure from msync().
> The following warning is output.
>
> "warning: qemu_ram_msync: failed to sync memory range“
>
> So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
>
> -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
>
> Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
> ---
> docs/nvdimm.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
> index c2c6e441b3..31048aff5e 100644
> --- a/docs/nvdimm.txt
> +++ b/docs/nvdimm.txt
> @@ -243,6 +243,13 @@ use the QEMU command line:
>
> -object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem=on
>
> +At the end of live migration, QEMU uses msync() to flush the data to the
> +backend storage. When the backend file is a character device dax, the pages
> +explicitly avoid the page cache. It will return failure from msync().
> +So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
> +
> + -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
> +
> References
> ----------
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
2020-07-15 2:54 [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file Jingqi Liu
2020-07-24 7:15 ` Liu, Jingqi
@ 2020-07-28 1:09 ` Liu, Jingqi
2020-07-29 10:42 ` Stefan Hajnoczi
2 siblings, 0 replies; 7+ messages in thread
From: Liu, Jingqi @ 2020-07-28 1:09 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel
Hi Paolo,
Any comments for this patch ?
Thanks,
Jingqi
On 7/15/2020 10:54 AM, Liu, Jingqi wrote:
> At the end of live migration, QEMU uses msync() to flush the data to
> the backend storage. When the backend file is a character device dax,
> the pages explicitly avoid the page cache. It will return failure from msync().
> The following warning is output.
>
> "warning: qemu_ram_msync: failed to sync memory range“
>
> So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
>
> -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
>
> Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
> ---
> docs/nvdimm.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
> index c2c6e441b3..31048aff5e 100644
> --- a/docs/nvdimm.txt
> +++ b/docs/nvdimm.txt
> @@ -243,6 +243,13 @@ use the QEMU command line:
>
> -object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem=on
>
> +At the end of live migration, QEMU uses msync() to flush the data to the
> +backend storage. When the backend file is a character device dax, the pages
> +explicitly avoid the page cache. It will return failure from msync().
> +So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
> +
> + -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
> +
> References
> ----------
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
2020-07-15 2:54 [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file Jingqi Liu
2020-07-24 7:15 ` Liu, Jingqi
2020-07-28 1:09 ` Liu, Jingqi
@ 2020-07-29 10:42 ` Stefan Hajnoczi
2 siblings, 0 replies; 7+ messages in thread
From: Stefan Hajnoczi @ 2020-07-29 10:42 UTC (permalink / raw)
To: Jingqi Liu; +Cc: Paolo Bonzini, Dan Williams, Xiao Guangrong, qemu-devel
[-- Attachment #1: Type: text/plain, Size: 742 bytes --]
On Wed, Jul 15, 2020 at 10:54:29AM +0800, Jingqi Liu wrote:
> At the end of live migration, QEMU uses msync() to flush the data to
> the backend storage. When the backend file is a character device dax,
> the pages explicitly avoid the page cache. It will return failure from msync().
> The following warning is output.
>
> "warning: qemu_ram_msync: failed to sync memory range“
>
> So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
>
> -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
>
> Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
> ---
> docs/nvdimm.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
[-- Attachment #2: signature.asc --]
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^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
@ 2020-07-30 1:02 Jingqi Liu
2020-07-30 5:07 ` Pankaj Gupta
0 siblings, 1 reply; 7+ messages in thread
From: Jingqi Liu @ 2020-07-30 1:02 UTC (permalink / raw)
To: Stefan Hajnoczi, Paolo Bonzini, Xiao Guangrong, Dan Williams
Cc: Jingqi Liu, qemu-devel
At the end of live migration, QEMU uses msync() to flush the data to
the backend storage. When the backend file is a character device dax,
the pages explicitly avoid the page cache. It will return failure from msync().
The following warning is output.
"warning: qemu_ram_msync: failed to sync memory range“
So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
-object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
---
docs/nvdimm.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
index c2c6e441b3..31048aff5e 100644
--- a/docs/nvdimm.txt
+++ b/docs/nvdimm.txt
@@ -243,6 +243,13 @@ use the QEMU command line:
-object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem=on
+At the end of live migration, QEMU uses msync() to flush the data to the
+backend storage. When the backend file is a character device dax, the pages
+explicitly avoid the page cache. It will return failure from msync().
+So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
+
+ -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
+
References
----------
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
2020-07-30 1:02 Jingqi Liu
@ 2020-07-30 5:07 ` Pankaj Gupta
0 siblings, 0 replies; 7+ messages in thread
From: Pankaj Gupta @ 2020-07-30 5:07 UTC (permalink / raw)
To: Jingqi Liu
Cc: Paolo Bonzini, Dan Williams, Xiao Guangrong, Stefan Hajnoczi, qemu-devel
> At the end of live migration, QEMU uses msync() to flush the data to
> the backend storage. When the backend file is a character device dax,
> the pages explicitly avoid the page cache. It will return failure from msync().
> The following warning is output.
>
> "warning: qemu_ram_msync: failed to sync memory range“
>
> So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
>
> -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
>
> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
> Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
> ---
> docs/nvdimm.txt | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
> index c2c6e441b3..31048aff5e 100644
> --- a/docs/nvdimm.txt
> +++ b/docs/nvdimm.txt
> @@ -243,6 +243,13 @@ use the QEMU command line:
>
> -object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem=on
>
> +At the end of live migration, QEMU uses msync() to flush the data to the
> +backend storage. When the backend file is a character device dax, the pages
> +explicitly avoid the page cache. It will return failure from msync().
> +So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
> +
> + -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
> +
> References
> ----------
>
> --
Good to document this.
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
> 2.17.1
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file
@ 2020-08-03 0:35 Jingqi Liu
0 siblings, 0 replies; 7+ messages in thread
From: Jingqi Liu @ 2020-08-03 0:35 UTC (permalink / raw)
To: Stefan Hajnoczi, Pankaj Gupta, Paolo Bonzini, Xiao Guangrong,
Dan Williams
Cc: Jingqi Liu, qemu-devel
At the end of live migration, QEMU uses msync() to flush the data to
the backend storage. When the backend file is a character device dax,
the pages explicitly avoid the page cache. It will return failure from msync().
The following warning is output.
"warning: qemu_ram_msync: failed to sync memory range“
So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
-object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Signed-off-by: Jingqi Liu <jingqi.liu@intel.com>
---
docs/nvdimm.txt | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/docs/nvdimm.txt b/docs/nvdimm.txt
index c2c6e441b3..31048aff5e 100644
--- a/docs/nvdimm.txt
+++ b/docs/nvdimm.txt
@@ -243,6 +243,13 @@ use the QEMU command line:
-object memory-backend-file,id=nv_mem,mem-path=/XXX/yyy,size=4G,pmem=on
+At the end of live migration, QEMU uses msync() to flush the data to the
+backend storage. When the backend file is a character device dax, the pages
+explicitly avoid the page cache. It will return failure from msync().
+So we add 'pmem=on' to avoid calling msync(), use the QEMU command line:
+
+ -object memory-backend-file,id=mem1,pmem=on,mem-path=/dev/dax0.0,size=4G
+
References
----------
--
2.17.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
end of thread, other threads:[~2020-08-03 0:46 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-07-15 2:54 [PATCH] docs/nvdimm: add 'pmem=on' for the device dax backend file Jingqi Liu
2020-07-24 7:15 ` Liu, Jingqi
2020-07-28 1:09 ` Liu, Jingqi
2020-07-29 10:42 ` Stefan Hajnoczi
2020-07-30 1:02 Jingqi Liu
2020-07-30 5:07 ` Pankaj Gupta
2020-08-03 0:35 Jingqi Liu
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