Patchwork [V5,1/4] Qemu: Enhance "info block" to display host cache setting

login
register
mail settings
Submitter Supriya Kannery
Date July 27, 2011, 11:30 a.m.
Message ID <20110727113014.25109.58868.sendpatchset@skannery>
Download mbox | patch
Permalink /patch/107031/
State New
Headers show

Comments

Supriya Kannery - July 27, 2011, 11:30 a.m.
Enhance "info block" to display hostcache setting for each
block device.

Example:
(qemu) info block
ide0-hd0: type=hd removable=0 file=../rhel6-32.qcow2 ro=0 drv=qcow2
encrypted=0

Enhanced to display "hostcache" setting:
(qemu) info block
ide0-hd0: type=hd removable=0 hostcache=true file=../rhel6-32.qcow2
ro=0 drv=qcow2 encrypted=0

Signed-off-by: Supriya Kannery <supriyak@in.ibm.com>

---
 block.c         |   21 +++++++++++++++++----
 qmp-commands.hx |    2 ++
 2 files changed, 19 insertions(+), 4 deletions(-)
Stefan Hajnoczi - July 27, 2011, 2:19 p.m.
On Wed, Jul 27, 2011 at 12:30 PM, Supriya Kannery
<supriyak@linux.vnet.ibm.com> wrote:
> Enhance "info block" to display hostcache setting for each
> block device.
>
> Example:
> (qemu) info block
> ide0-hd0: type=hd removable=0 file=../rhel6-32.qcow2 ro=0 drv=qcow2
> encrypted=0
>
> Enhanced to display "hostcache" setting:
> (qemu) info block
> ide0-hd0: type=hd removable=0 hostcache=true file=../rhel6-32.qcow2
> ro=0 drv=qcow2 encrypted=0

This description is outdated, should be hostcache=1 instead of hostcache=true.

> @@ -1749,13 +1757,18 @@ void bdrv_info(Monitor *mon, QObject **r
>         QObject *bs_obj;
>
>         bs_obj = qobject_from_jsonf("{ 'device': %s, 'type': 'unknown', "
> -                                    "'removable': %i, 'locked': %i }",
> -                                    bs->device_name, bs->removable,
> -                                    bs->locked);
> +                                     "'removable': %i, 'locked': %i, "
> +                                     "'hostcache': %s }",
> +                                     bs->device_name, bs->removable,
> +                                     bs->locked,
> +                                     (bs->open_flags & BDRV_O_NOCACHE) ?
> +                                     "false" : "true");

Please use the same bool-from-int format specifier ('%i') as the other
fields for consistency.  The value can be !(bs->open_flags &
BDRV_O_NOCACHE).

> +
> +        QDict *bs_dict = qobject_to_qdict(bs_obj);
> +        qdict_put(bs_dict, "open_flags", qint_from_int(bs->open_flags));
>
>         if (bs->drv) {
>             QObject *obj;
> -            QDict *bs_dict = qobject_to_qdict(bs_obj);
>
>             obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
>                                      "'encrypted': %i }",

My copy of the code has the following a few lines further down:
qdict_put_obj(bs_dict, "inserted", obj);

Removing bs_dict would break the build.  Am I missing something?

> Index: qemu/qmp-commands.hx
> ===================================================================
> --- qemu.orig/qmp-commands.hx
> +++ qemu/qmp-commands.hx
> @@ -1131,6 +1131,7 @@ Each json-object contain the following:
>          - Possible values: "unknown"
>  - "removable": true if the device is removable, false otherwise (json-bool)
>  - "locked": true if the device is locked, false otherwise (json-bool)
> +- "hostcache": true if hostcache enabled, false otherwise (json-bool)

Let's explain what "hostcache" means:

- "hostcache": true if host page cache is enabled, false otherwise (json-bool)

Stefan
supriya kannery - July 28, 2011, 10:39 a.m.
On 07/27/2011 07:49 PM, Stefan Hajnoczi wrote:
> On Wed, Jul 27, 2011 at 12:30 PM, Supriya Kannery
> <supriyak@linux.vnet.ibm.com>  wrote:
>> Enhance "info block" to display hostcache setting for each
>> block device.
>>
>> Example:
>> (qemu) info block
>> ide0-hd0: type=hd removable=0 file=../rhel6-32.qcow2 ro=0 drv=qcow2
>> encrypted=0
>>
>> Enhanced to display "hostcache" setting:
>> (qemu) info block
>> ide0-hd0: type=hd removable=0 hostcache=true file=../rhel6-32.qcow2
>> ro=0 drv=qcow2 encrypted=0
>
> This description is outdated, should be hostcache=1 instead of hostcache=true.
>
>> @@ -1749,13 +1757,18 @@ void bdrv_info(Monitor *mon, QObject **r
>>          QObject *bs_obj;
>>
>>          bs_obj = qobject_from_jsonf("{ 'device': %s, 'type': 'unknown', "
>> -                                    "'removable': %i, 'locked': %i }",
>> -                                    bs->device_name, bs->removable,
>> -                                    bs->locked);
>> +                                     "'removable': %i, 'locked': %i, "
>> +                                     "'hostcache': %s }",
>> +                                     bs->device_name, bs->removable,
>> +                                     bs->locked,
>> +                                     (bs->open_flags&  BDRV_O_NOCACHE) ?
>> +                                     "false" : "true");
>
> Please use the same bool-from-int format specifier ('%i') as the other
> fields for consistency.  The value can be !(bs->open_flags&
> BDRV_O_NOCACHE).
>

ok

>> +
>> +        QDict *bs_dict = qobject_to_qdict(bs_obj);
>> +        qdict_put(bs_dict, "open_flags", qint_from_int(bs->open_flags));
>>
>>          if (bs->drv) {
>>              QObject *obj;
>> -            QDict *bs_dict = qobject_to_qdict(bs_obj);
>>
>>              obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
>>                                       "'encrypted': %i }",
>
> My copy of the code has the following a few lines further down:
> qdict_put_obj(bs_dict, "inserted", obj);
>
> Removing bs_dict would break the build.  Am I missing something?
>

qdict_put_obj() for "inserted" is still there further down in the code.
Here,
   QDict *bs_dict = qobject_to_qdict(bs_obj);
is moved up to enable placing of "open_flags" into the dict. We need 
"open_flags" in dict to calculate hostcache value for printing in
monitor. Code for placing "inserted" is not touched.

>> Index: qemu/qmp-commands.hx
>> ===================================================================
>> --- qemu.orig/qmp-commands.hx
>> +++ qemu/qmp-commands.hx
>> @@ -1131,6 +1131,7 @@ Each json-object contain the following:
>>           - Possible values: "unknown"
>>   - "removable": true if the device is removable, false otherwise (json-bool)
>>   - "locked": true if the device is locked, false otherwise (json-bool)
>> +- "hostcache": true if hostcache enabled, false otherwise (json-bool)
>
> Let's explain what "hostcache" means:
>
> - "hostcache": true if host page cache is enabled, false otherwise (json-bool)
>

ok

-Thanks, Supriya

> Stefan

Patch

Index: qemu/block.c
===================================================================
--- qemu.orig/block.c
+++ qemu/block.c
@@ -1713,6 +1713,14 @@  static void bdrv_print_dict(QObject *obj
         monitor_printf(mon, " locked=%d", qdict_get_bool(bs_dict, "locked"));
     }
 
+    if (qdict_haskey(bs_dict, "open_flags")) {
+        int open_flags = qdict_get_int(bs_dict, "open_flags");
+        if (open_flags & BDRV_O_NOCACHE)
+            monitor_printf(mon, " hostcache=0");
+        else
+            monitor_printf(mon, " hostcache=1");
+    }
+
     if (qdict_haskey(bs_dict, "inserted")) {
         QDict *qdict = qobject_to_qdict(qdict_get(bs_dict, "inserted"));
 
@@ -1749,13 +1757,18 @@  void bdrv_info(Monitor *mon, QObject **r
         QObject *bs_obj;
 
         bs_obj = qobject_from_jsonf("{ 'device': %s, 'type': 'unknown', "
-                                    "'removable': %i, 'locked': %i }",
-                                    bs->device_name, bs->removable,
-                                    bs->locked);
+                                     "'removable': %i, 'locked': %i, "
+                                     "'hostcache': %s }",
+                                     bs->device_name, bs->removable,
+                                     bs->locked,
+                                     (bs->open_flags & BDRV_O_NOCACHE) ?
+                                     "false" : "true");
+
+        QDict *bs_dict = qobject_to_qdict(bs_obj);
+        qdict_put(bs_dict, "open_flags", qint_from_int(bs->open_flags));
 
         if (bs->drv) {
             QObject *obj;
-            QDict *bs_dict = qobject_to_qdict(bs_obj);
 
             obj = qobject_from_jsonf("{ 'file': %s, 'ro': %i, 'drv': %s, "
                                      "'encrypted': %i }",
Index: qemu/qmp-commands.hx
===================================================================
--- qemu.orig/qmp-commands.hx
+++ qemu/qmp-commands.hx
@@ -1131,6 +1131,7 @@  Each json-object contain the following:
          - Possible values: "unknown"
 - "removable": true if the device is removable, false otherwise (json-bool)
 - "locked": true if the device is locked, false otherwise (json-bool)
+- "hostcache": true if hostcache enabled, false otherwise (json-bool)
 - "inserted": only present if the device is inserted, it is a json-object
    containing the following:
          - "file": device file name (json-string)
@@ -1152,6 +1153,7 @@  Example:
          {
             "device":"ide0-hd0",
             "locked":false,
+            "hostcache":false,
             "removable":false,
             "inserted":{
                "ro":false,