2019-08-10 18:00:26

by Sourabh Jain

[permalink] [raw]
Subject: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation

Add a sys interface to allow querying the memory reserved by
fadump for saving the crash dump.

Add an ABI doc entry for new sysfs interface.
- /sys/kernel/fadump_mem_reserved

Signed-off-by: Sourabh Jain <[email protected]>
---
Changelog:
v1 -> v2:
- Added ABI doc for new sysfs interface.

v2 -> v3:
- Updated the ABI documentation.
---

Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
Documentation/powerpc/firmware-assisted-dump.rst | 5 +++++
arch/powerpc/kernel/fadump.c | 14 ++++++++++++++
3 files changed, 25 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-kernel-fadump

diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump
new file mode 100644
index 000000000000..ec034939475b
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-kernel-fadump
@@ -0,0 +1,6 @@
+What: /sys/kernel/fadump_mem_reserved
+Date: August 2019
+Contact: [email protected]
+Description: read only
+ Provide information about the amount of memory
+ reserved by fadump to save the crash dump.
diff --git a/Documentation/powerpc/firmware-assisted-dump.rst b/Documentation/powerpc/firmware-assisted-dump.rst
index 9ca12830a48e..a5dfb20d4dc3 100644
--- a/Documentation/powerpc/firmware-assisted-dump.rst
+++ b/Documentation/powerpc/firmware-assisted-dump.rst
@@ -222,6 +222,11 @@ Here is the list of files under kernel sysfs:
be handled and vmcore will not be captured. This interface can be
easily integrated with kdump service start/stop.

+ /sys/kernel/fadump_mem_reserved
+
+ This is used to display the memory reserved by fadump for saving the
+ crash dump.
+
/sys/kernel/fadump_release_mem
This file is available only when fadump is active during
second kernel. This is used to release the reserved memory
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 4eab97292cc2..cd373d1d4b82 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1514,6 +1514,13 @@ static ssize_t fadump_enabled_show(struct kobject *kobj,
return sprintf(buf, "%d\n", fw_dump.fadump_enabled);
}

+static ssize_t fadump_mem_reserved_show(struct kobject *kobj,
+ struct kobj_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%ld\n", fw_dump.reserve_dump_area_size);
+}
+
static ssize_t fadump_register_show(struct kobject *kobj,
struct kobj_attribute *attr,
char *buf)
@@ -1632,6 +1639,9 @@ static struct kobj_attribute fadump_attr = __ATTR(fadump_enabled,
static struct kobj_attribute fadump_register_attr = __ATTR(fadump_registered,
0644, fadump_register_show,
fadump_register_store);
+static struct kobj_attribute fadump_mem_reserved_attr =
+ __ATTR(fadump_mem_reserved, 0444,
+ fadump_mem_reserved_show, NULL);

DEFINE_SHOW_ATTRIBUTE(fadump_region);

@@ -1663,6 +1673,10 @@ static void fadump_init_files(void)
printk(KERN_ERR "fadump: unable to create sysfs file"
" fadump_release_mem (%d)\n", rc);
}
+ rc = sysfs_create_file(kernel_kobj, &fadump_mem_reserved_attr.attr);
+ if (rc)
+ pr_err("unable to create sysfs file fadump_mem_reserved (%d)\n",
+ rc);
return;
}

--
2.17.2


2019-08-26 10:33:09

by Hari Bathini

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation



On 10/08/19 11:29 PM, Sourabh Jain wrote:
> Add a sys interface to allow querying the memory reserved by
> fadump for saving the crash dump.
>
> Add an ABI doc entry for new sysfs interface.
> - /sys/kernel/fadump_mem_reserved
>
> Signed-off-by: Sourabh Jain <[email protected]>
> ---
> Changelog:
> v1 -> v2:
> - Added ABI doc for new sysfs interface.
>
> v2 -> v3:
> - Updated the ABI documentation.
> ---
>
> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++

Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?

> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
> @@ -0,0 +1,6 @@
> +What: /sys/kernel/fadump_mem_reserved
> +Date: August 2019
> +Contact: [email protected]
> +Description: read only
> + Provide information about the amount of memory
> + reserved by fadump to save the crash dump.

Split this up into a separate patch and have ABI documentation for
fadump_reserved & fadump_registered as well..

Thanks
Hari

2019-08-26 10:48:16

by Sourabh Jain

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation



On 8/26/19 3:46 PM, Sourabh Jain wrote:
>
>
> On 8/26/19 3:29 PM, Hari Bathini wrote:
>>
>>
>> On 10/08/19 11:29 PM, Sourabh Jain wrote:
>>> Add a sys interface to allow querying the memory reserved by
>>> fadump for saving the crash dump.
>>>
>>> Add an ABI doc entry for new sysfs interface.
>>> - /sys/kernel/fadump_mem_reserved
>>>
>>> Signed-off-by: Sourabh Jain <[email protected]>
>>> ---
>>> Changelog:
>>> v1 -> v2:
>>> - Added ABI doc for new sysfs interface.
>>>
>>> v2 -> v3:
>>> - Updated the ABI documentation.
>>> ---
>>>
>>> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
>>
>> Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?

How about documenting fadump_mem_reserved and other sysfs attributes suggested
by you in a single file Documentation/ABI/testing/sysfs-kernel-fadump?

>>
>>> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
>>> @@ -0,0 +1,6 @@
>>> +What: /sys/kernel/fadump_mem_reserved
>>> +Date: August 2019
>>> +Contact: [email protected]
>>> +Description: read only
>>> + Provide information about the amount of memory
>>> + reserved by fadump to save the crash dump.
>>
>> Split this up into a separate patch and have ABI documentation for
>> fadump_reserved & fadump_registered as well..

- Sourabh Jain

2019-08-26 11:37:16

by Hari Bathini

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation



On 26/08/19 4:14 PM, Sourabh Jain wrote:
>
>
> On 8/26/19 3:46 PM, Sourabh Jain wrote:
>>
>>
>> On 8/26/19 3:29 PM, Hari Bathini wrote:
>>>
>>>
>>> On 10/08/19 11:29 PM, Sourabh Jain wrote:
>>>> Add a sys interface to allow querying the memory reserved by
>>>> fadump for saving the crash dump.
>>>>
>>>> Add an ABI doc entry for new sysfs interface.
>>>> - /sys/kernel/fadump_mem_reserved
>>>>
>>>> Signed-off-by: Sourabh Jain <[email protected]>
>>>> ---
>>>> Changelog:
>>>> v1 -> v2:
>>>> - Added ABI doc for new sysfs interface.
>>>>
>>>> v2 -> v3:
>>>> - Updated the ABI documentation.
>>>> ---
>>>>
>>>> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
>>>
>>> Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?
>
> How about documenting fadump_mem_reserved and other sysfs attributes suggested
> by you in a single file Documentation/ABI/testing/sysfs-kernel-fadump?

I wouldn't mind that but please do check if it is breaking a convention..

- Hari

2019-08-26 12:45:20

by Sourabh Jain

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation



On 8/26/19 3:29 PM, Hari Bathini wrote:
>
>
> On 10/08/19 11:29 PM, Sourabh Jain wrote:
>> Add a sys interface to allow querying the memory reserved by
>> fadump for saving the crash dump.
>>
>> Add an ABI doc entry for new sysfs interface.
>> - /sys/kernel/fadump_mem_reserved
>>
>> Signed-off-by: Sourabh Jain <[email protected]>
>> ---
>> Changelog:
>> v1 -> v2:
>> - Added ABI doc for new sysfs interface.
>>
>> v2 -> v3:
>> - Updated the ABI documentation.
>> ---
>>
>> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
>
> Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?
>
>> +++ b/Documentation/ABI/testing/sysfs-kernel-fadump
>> @@ -0,0 +1,6 @@
>> +What: /sys/kernel/fadump_mem_reserved
>> +Date: August 2019
>> +Contact: [email protected]
>> +Description: read only
>> + Provide information about the amount of memory
>> + reserved by fadump to save the crash dump.
>
> Split this up into a separate patch and have ABI documentation for
> fadump_reserved & fadump_registered as well..


Sure. Thanks for review.


- Sourabh Jain

2019-08-27 03:20:56

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation

Hari Bathini <[email protected]> writes:
> On 26/08/19 4:14 PM, Sourabh Jain wrote:
>> On 8/26/19 3:46 PM, Sourabh Jain wrote:
>>> On 8/26/19 3:29 PM, Hari Bathini wrote:
>>>> On 10/08/19 11:29 PM, Sourabh Jain wrote:
>>>>> Add a sys interface to allow querying the memory reserved by
>>>>> fadump for saving the crash dump.
>>>>>
>>>>> Add an ABI doc entry for new sysfs interface.
>>>>> - /sys/kernel/fadump_mem_reserved
>>>>>
>>>>> Signed-off-by: Sourabh Jain <[email protected]>
>>>>> ---
>>>>> Changelog:
>>>>> v1 -> v2:
>>>>> - Added ABI doc for new sysfs interface.
>>>>>
>>>>> v2 -> v3:
>>>>> - Updated the ABI documentation.
>>>>> ---
>>>>>
>>>>> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
>>>>
>>>> Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?
>>
>> How about documenting fadump_mem_reserved and other sysfs attributes suggested
>> by you in a single file Documentation/ABI/testing/sysfs-kernel-fadump?
>
> I wouldn't mind that but please do check if it is breaking a convention..

AIUI a file named like that would hold the documentation for the files
inside a directory called /sys/kernel/fadump.

And in fact that's probably where these files should live, rather than
just dropped directly into /sys/kernel.

cheers

2019-08-27 06:05:47

by Hari Bathini

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation



On 27/08/19 8:49 AM, Michael Ellerman wrote:
> Hari Bathini <[email protected]> writes:
>> On 26/08/19 4:14 PM, Sourabh Jain wrote:
>>> On 8/26/19 3:46 PM, Sourabh Jain wrote:
>>>> On 8/26/19 3:29 PM, Hari Bathini wrote:
>>>>> On 10/08/19 11:29 PM, Sourabh Jain wrote:
>>>>>> Add a sys interface to allow querying the memory reserved by
>>>>>> fadump for saving the crash dump.
>>>>>>
>>>>>> Add an ABI doc entry for new sysfs interface.
>>>>>> - /sys/kernel/fadump_mem_reserved
>>>>>>
>>>>>> Signed-off-by: Sourabh Jain <[email protected]>
>>>>>> ---
>>>>>> Changelog:
>>>>>> v1 -> v2:
>>>>>> - Added ABI doc for new sysfs interface.
>>>>>>
>>>>>> v2 -> v3:
>>>>>> - Updated the ABI documentation.
>>>>>> ---
>>>>>>
>>>>>> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
>>>>>
>>>>> Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?
>>>
>>> How about documenting fadump_mem_reserved and other sysfs attributes suggested
>>> by you in a single file Documentation/ABI/testing/sysfs-kernel-fadump?
>>
>> I wouldn't mind that but please do check if it is breaking a convention..
>
> AIUI a file named like that would hold the documentation for the files
> inside a directory called /sys/kernel/fadump.
>
> And in fact that's probably where these files should live, rather than
> just dropped directly into /sys/kernel.
Michael, could that be corrected now by introducing new sysfs files for FADump in
/sys/kernel/fadump/.

Also, duplicating current /sys/kernel/fadump_* files as /sys/kernel/fadump/* files
& eventually dropping /sys/kernel/fadump_* files sometime later..

- Hari

2019-09-18 09:33:36

by Sourabh Jain

[permalink] [raw]
Subject: Re: [PATCH v3] powerpc/fadump: sysfs for fadump memory reservation



On 8/27/19 11:32 AM, Hari Bathini wrote:
>
>
> On 27/08/19 8:49 AM, Michael Ellerman wrote:
>> Hari Bathini <[email protected]> writes:
>>> On 26/08/19 4:14 PM, Sourabh Jain wrote:
>>>> On 8/26/19 3:46 PM, Sourabh Jain wrote:
>>>>> On 8/26/19 3:29 PM, Hari Bathini wrote:
>>>>>> On 10/08/19 11:29 PM, Sourabh Jain wrote:
>>>>>>> Add a sys interface to allow querying the memory reserved by
>>>>>>> fadump for saving the crash dump.
>>>>>>>
>>>>>>> Add an ABI doc entry for new sysfs interface.
>>>>>>> - /sys/kernel/fadump_mem_reserved
>>>>>>>
>>>>>>> Signed-off-by: Sourabh Jain <[email protected]>
>>>>>>> ---
>>>>>>> Changelog:
>>>>>>> v1 -> v2:
>>>>>>> - Added ABI doc for new sysfs interface.
>>>>>>>
>>>>>>> v2 -> v3:
>>>>>>> - Updated the ABI documentation.
>>>>>>> ---
>>>>>>>
>>>>>>> Documentation/ABI/testing/sysfs-kernel-fadump | 6 ++++++
>>>>>>
>>>>>> Shouldn't this be Documentation/ABI/testing/sysfs-kernel-fadump_mem_reserved?
>>>>
>>>> How about documenting fadump_mem_reserved and other sysfs attributes suggested
>>>> by you in a single file Documentation/ABI/testing/sysfs-kernel-fadump?
>>>
>>> I wouldn't mind that but please do check if it is breaking a convention..
>>
>> AIUI a file named like that would hold the documentation for the files
>> inside a directory called /sys/kernel/fadump.
>>
>> And in fact that's probably where these files should live, rather than
>> just dropped directly into /sys/kernel.
> Michael, could that be corrected now by introducing new sysfs files for FADump in
> /sys/kernel/fadump/.
>
> Also, duplicating current /sys/kernel/fadump_* files as /sys/kernel/fadump/* files
> & eventually dropping /sys/kernel/fadump_* files sometime later..


Sent a patch series that adds fadump_mem_reserved sysfs file along with reorganizing
the existing fadump sysfs files.

Patch series available here:
https://lists.ozlabs.org/pipermail/linuxppc-dev/2019-September/197100.html

- Sourabh Jain