Re: [Xen-devel] [PATCH v2 1/2] xen: add config option to include failing condition in BUG_ON() message
On 17.01.20 09:39, Jan Beulich wrote: On 16.01.2020 19:54, Andrew Cooper wrote: On 14/01/2020 16:12, Jan Beulich wrote: On 14.01.2020 17:00, Jürgen Groß wrote: On 14.01.20 16:47, Jan Beulich wrote: On 09.01.2020 14:48, Juergen Gross wrote: --- a/xen/Kconfig.debug +++ b/xen/Kconfig.debug @@ -81,6 +81,12 @@ config PERF_ARRAYS ---help--- Enables software performance counter array histograms. +config DEBUG_BUGVERBOSE + bool "Verbose BUG_ON messages" + default DEBUG + ---help--- + In case a BUG_ON triggers additionally print the triggering + condition on the console. config VERBOSE_DEBUG While I can see reasons to put this here, doing so means the option will be unavailable in non-EXPERT release builds. Is it intended to be that way? I can move it either to xen/Kconfig or in Kconfig.debug out of the "if expert" section if you want. I think this would be better, but give others a chance to voice opinions. TBH, I don't think anyone will be interested in not having the strings. The change is what? a couple of hundred bytes? That is a fraction of the size of some functions we have. Well, it's a couple thousand (about 7k according to my simplistic estimation, but this is taking Arm and x86 together). It's not the end of the world, but in particular embedded users may want to get rid of this. There's a reason after all (I assume) that Linux has the option. The needed code churn is rather limited, so I think we should keep the config option. Juergen ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] [PATCH v2 1/2] xen: add config option to include failing condition in BUG_ON() message
On 16.01.2020 19:54, Andrew Cooper wrote: > On 14/01/2020 16:12, Jan Beulich wrote: >> On 14.01.2020 17:00, Jürgen Groß wrote: >>> On 14.01.20 16:47, Jan Beulich wrote: On 09.01.2020 14:48, Juergen Gross wrote: > --- a/xen/Kconfig.debug > +++ b/xen/Kconfig.debug > @@ -81,6 +81,12 @@ config PERF_ARRAYS > ---help--- > Enables software performance counter array histograms. > > +config DEBUG_BUGVERBOSE > + bool "Verbose BUG_ON messages" > + default DEBUG > + ---help--- > + In case a BUG_ON triggers additionally print the triggering > + condition on the console. > > config VERBOSE_DEBUG While I can see reasons to put this here, doing so means the option will be unavailable in non-EXPERT release builds. Is it intended to be that way? >>> I can move it either to xen/Kconfig or in Kconfig.debug out of the >>> "if expert" section if you want. >> I think this would be better, but give others a chance to voice >> opinions. > > TBH, I don't think anyone will be interested in not having the strings. > The change is what? a couple of hundred bytes? That is a fraction of > the size of some functions we have. Well, it's a couple thousand (about 7k according to my simplistic estimation, but this is taking Arm and x86 together). It's not the end of the world, but in particular embedded users may want to get rid of this. There's a reason after all (I assume) that Linux has the option. Jan ___ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
Re: [Xen-devel] [PATCH v2 1/2] xen: add config option to include failing condition in BUG_ON() message
On 14/01/2020 16:12, Jan Beulich wrote:
> On 14.01.2020 17:00, Jürgen Groß wrote:
>> On 14.01.20 16:47, Jan Beulich wrote:
>>> On 09.01.2020 14:48, Juergen Gross wrote:
--- a/xen/Kconfig.debug
+++ b/xen/Kconfig.debug
@@ -81,6 +81,12 @@ config PERF_ARRAYS
---help---
Enables software performance counter array histograms.
+config DEBUG_BUGVERBOSE
+ bool "Verbose BUG_ON messages"
+ default DEBUG
+ ---help---
+In case a BUG_ON triggers additionally print the triggering
+condition on the console.
config VERBOSE_DEBUG
>>> While I can see reasons to put this here, doing so means the option
>>> will be unavailable in non-EXPERT release builds. Is it intended to
>>> be that way?
>> I can move it either to xen/Kconfig or in Kconfig.debug out of the
>> "if expert" section if you want.
> I think this would be better, but give others a chance to voice
> opinions.
TBH, I don't think anyone will be interested in not having the strings.
The change is what? a couple of hundred bytes? That is a fraction of
the size of some functions we have.
Personally, I wouldn't even bother having the option.
>
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -8,7 +8,12 @@
#include
#include
+#define BUG_ON_VERBOSE(p) do { if (unlikely(p)) BUG_VERBOSE(#p); } while
(0)
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define BUG_ON(p) BUG_ON_VERBOSE(p)
>>> Looks like this will fail to build on Arm? Also - any particular
>> Uh, shame on me!
>>
>>> reason for the introduction of the separate BUG_ON_VERBOSE(),
>>> when BUG_ON() could directly use BUG_VERBOSE()? I don't think we
>>> want to encourage use of BUG_ON_VERBOSE() elsewhere ...
>> I wanted to offer that option. If you want me to remove it I wouldn't
>> mind.
> As above - unless there are good reasons (making others to agree
> with you to have it), I'd prefer to not see it being independently
> usable, at least for the time being.
I'd agree with the wish to not have a new flavour of BUG_ON().
People writing code aren't going to want the complexity of thinking
about it, and people who care about the presence/absence of messages
will care about it globally, not on a per-use bases.
~Andrew
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Re: [Xen-devel] [PATCH v2 1/2] xen: add config option to include failing condition in BUG_ON() message
On 14.01.2020 17:00, Jürgen Groß wrote:
> On 14.01.20 16:47, Jan Beulich wrote:
>> On 09.01.2020 14:48, Juergen Gross wrote:
>>> --- a/xen/Kconfig.debug
>>> +++ b/xen/Kconfig.debug
>>> @@ -81,6 +81,12 @@ config PERF_ARRAYS
>>> ---help---
>>> Enables software performance counter array histograms.
>>>
>>> +config DEBUG_BUGVERBOSE
>>> + bool "Verbose BUG_ON messages"
>>> + default DEBUG
>>> + ---help---
>>> + In case a BUG_ON triggers additionally print the triggering
>>> + condition on the console.
>>>
>>> config VERBOSE_DEBUG
>>
>> While I can see reasons to put this here, doing so means the option
>> will be unavailable in non-EXPERT release builds. Is it intended to
>> be that way?
>
> I can move it either to xen/Kconfig or in Kconfig.debug out of the
> "if expert" section if you want.
I think this would be better, but give others a chance to voice
opinions.
>>> --- a/xen/include/xen/lib.h
>>> +++ b/xen/include/xen/lib.h
>>> @@ -8,7 +8,12 @@
>>> #include
>>> #include
>>>
>>> +#define BUG_ON_VERBOSE(p) do { if (unlikely(p)) BUG_VERBOSE(#p); } while
>>> (0)
>>> +#ifdef CONFIG_DEBUG_BUGVERBOSE
>>> +#define BUG_ON(p) BUG_ON_VERBOSE(p)
>>
>> Looks like this will fail to build on Arm? Also - any particular
>
> Uh, shame on me!
>
>> reason for the introduction of the separate BUG_ON_VERBOSE(),
>> when BUG_ON() could directly use BUG_VERBOSE()? I don't think we
>> want to encourage use of BUG_ON_VERBOSE() elsewhere ...
>
> I wanted to offer that option. If you want me to remove it I wouldn't
> mind.
As above - unless there are good reasons (making others to agree
with you to have it), I'd prefer to not see it being independently
usable, at least for the time being.
Jan
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Re: [Xen-devel] [PATCH v2 1/2] xen: add config option to include failing condition in BUG_ON() message
On 14.01.20 16:47, Jan Beulich wrote:
On 09.01.2020 14:48, Juergen Gross wrote:
--- a/xen/Kconfig.debug
+++ b/xen/Kconfig.debug
@@ -81,6 +81,12 @@ config PERF_ARRAYS
---help---
Enables software performance counter array histograms.
+config DEBUG_BUGVERBOSE
+ bool "Verbose BUG_ON messages"
+ default DEBUG
+ ---help---
+ In case a BUG_ON triggers additionally print the triggering
+ condition on the console.
config VERBOSE_DEBUG
While I can see reasons to put this here, doing so means the option
will be unavailable in non-EXPERT release builds. Is it intended to
be that way?
I can move it either to xen/Kconfig or in Kconfig.debug out of the
"if expert" section if you want.
--- a/xen/include/xen/lib.h
+++ b/xen/include/xen/lib.h
@@ -8,7 +8,12 @@
#include
#include
+#define BUG_ON_VERBOSE(p) do { if (unlikely(p)) BUG_VERBOSE(#p); } while (0)
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define BUG_ON(p) BUG_ON_VERBOSE(p)
Looks like this will fail to build on Arm? Also - any particular
Uh, shame on me!
reason for the introduction of the separate BUG_ON_VERBOSE(),
when BUG_ON() could directly use BUG_VERBOSE()? I don't think we
want to encourage use of BUG_ON_VERBOSE() elsewhere ...
I wanted to offer that option. If you want me to remove it I wouldn't
mind.
Juergen
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Re: [Xen-devel] [PATCH v2 1/2] xen: add config option to include failing condition in BUG_ON() message
On 09.01.2020 14:48, Juergen Gross wrote:
> --- a/xen/Kconfig.debug
> +++ b/xen/Kconfig.debug
> @@ -81,6 +81,12 @@ config PERF_ARRAYS
> ---help---
> Enables software performance counter array histograms.
>
> +config DEBUG_BUGVERBOSE
> + bool "Verbose BUG_ON messages"
> + default DEBUG
> + ---help---
> + In case a BUG_ON triggers additionally print the triggering
> + condition on the console.
>
> config VERBOSE_DEBUG
While I can see reasons to put this here, doing so means the option
will be unavailable in non-EXPERT release builds. Is it intended to
be that way?
> --- a/xen/include/xen/lib.h
> +++ b/xen/include/xen/lib.h
> @@ -8,7 +8,12 @@
> #include
> #include
>
> +#define BUG_ON_VERBOSE(p) do { if (unlikely(p)) BUG_VERBOSE(#p); } while (0)
> +#ifdef CONFIG_DEBUG_BUGVERBOSE
> +#define BUG_ON(p) BUG_ON_VERBOSE(p)
Looks like this will fail to build on Arm? Also - any particular
reason for the introduction of the separate BUG_ON_VERBOSE(),
when BUG_ON() could directly use BUG_VERBOSE()? I don't think we
want to encourage use of BUG_ON_VERBOSE() elsewhere ...
Jan
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