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[PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL

Started byBabu Moger <babu.moger@oracle.com>
First post2016-09-27 00:40 +0200
Last post2016-09-27 18:30 +0200
Articles 6 — 3 participants

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  [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL Babu Moger <babu.moger@oracle.com> - 2016-09-27 00:40 +0200
    Re: [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL Sam Ravnborg <sam@ravnborg.org> - 2016-09-27 07:00 +0200
      Re: [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL Peter Zijlstra <peterz@infradead.org> - 2016-09-27 13:50 +0200
        Re: [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL Babu Moger <babu.moger@oracle.com> - 2016-09-27 17:00 +0200
          Re: [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL Sam Ravnborg <sam@ravnborg.org> - 2016-09-27 17:50 +0200
            Re: [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL Babu Moger <babu.moger@oracle.com> - 2016-09-27 18:30 +0200

#1491591 — [PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL

FromBabu Moger <babu.moger@oracle.com>
Date2016-09-27 00:40 +0200
Subject[PATCH v2 1/2] config: Add new CONFIG_PROVE_LOCKING_SMALL
Message-ID<slMJ3-1gp-9@gated-at.bofh.it>
Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc.

This feature limits the space used for "Lock debugging: prove locking
correctness" by about 4MB. The current sparc systms have the limitation of
32MB size for kernel size including .text, .data and .bss sections. With
PROVE_LOCKING feature, the kernel size could grow beyond this limit and
causing system bootup issues. With this option, kernel limits the size
of the entries of lock_chains, stack_trace etc. so that kernel fits in
required size limit.  This is only visible for sparc.

Signed-off-by: Babu Moger <babu.moger@oracle.com>
---
 lib/Kconfig.debug |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index b9cfdbf..c79de25 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1035,6 +1035,7 @@ config PROVE_LOCKING
 	select DEBUG_MUTEXES
 	select DEBUG_LOCK_ALLOC
 	select TRACE_IRQFLAGS
+	select PROVE_LOCKING_SMALL if SPARC
 	default n
 	help
 	 This feature enables the kernel to prove that all locking
@@ -1070,6 +1071,22 @@ config PROVE_LOCKING
 
 	 For more details, see Documentation/locking/lockdep-design.txt.
 
+config PROVE_LOCKING_SMALL
+	bool "Limit the space for prove locking correctness"
+	depends on PROVE_LOCKING && SPARC
+	help
+	 This feature limits the space used for "Lock debugging: prove
+	 locking correctness" by about 4MB. In sparc system, all the
+	 kernel's code, data, and bss, must have locked translations in
+	 the TLB so that it does not hit TLB misses. The current sparc
+	 chips have 8 TLB entries available that may be locked down, and
+	 with a 4mb page size, this gives a maximum of 32mb of memory for
+	 the kernel size. With PROVE_LOCKING feature, the kernel size could
+	 grow beyond this limit and causing system bootup issues. With
+	 this option, kernel limits the size of the entries of lock_chains,
+	 stack_trace etc. to debug PROVE_LOCKING so that kernel size fits
+	 in 32MB. This is only visible for SPARC.
+
 config LOCKDEP
 	bool
 	depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT
-- 
1.7.1

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#1491682

FromSam Ravnborg <sam@ravnborg.org>
Date2016-09-27 07:00 +0200
Message-ID<slSEO-54F-11@gated-at.bofh.it>
In reply to#1491591
Hi Babu.

On Mon, Sep 26, 2016 at 03:31:37PM -0700, Babu Moger wrote:
> Adding the new config parameter CONFIG_PROVE_LOCKING_SMALL for sparc.
> 
> This feature limits the space used for "Lock debugging: prove locking
> correctness" by about 4MB. The current sparc systms have the limitation of
> 32MB size for kernel size including .text, .data and .bss sections. With
> PROVE_LOCKING feature, the kernel size could grow beyond this limit and
> causing system bootup issues. With this option, kernel limits the size
> of the entries of lock_chains, stack_trace etc. so that kernel fits in
> required size limit.  This is only visible for sparc.
> 
> Signed-off-by: Babu Moger <babu.moger@oracle.com>
> ---
>  lib/Kconfig.debug |   17 +++++++++++++++++
>  1 files changed, 17 insertions(+), 0 deletions(-)
> 
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index b9cfdbf..c79de25 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1035,6 +1035,7 @@ config PROVE_LOCKING
>  	select DEBUG_MUTEXES
>  	select DEBUG_LOCK_ALLOC
>  	select TRACE_IRQFLAGS
> +	select PROVE_LOCKING_SMALL if SPARC
>  	default n
>  	help
>  	 This feature enables the kernel to prove that all locking
> @@ -1070,6 +1071,22 @@ config PROVE_LOCKING
>  
>  	 For more details, see Documentation/locking/lockdep-design.txt.
>  
> +config PROVE_LOCKING_SMALL
> +	bool "Limit the space for prove locking correctness"
> +	depends on PROVE_LOCKING && SPARC
> +	help
> +	 This feature limits the space used for "Lock debugging: prove
> +	 locking correctness" by about 4MB. In sparc system, all the
> +	 kernel's code, data, and bss, must have locked translations in
> +	 the TLB so that it does not hit TLB misses. The current sparc
> +	 chips have 8 TLB entries available that may be locked down, and
> +	 with a 4mb page size, this gives a maximum of 32mb of memory for
> +	 the kernel size. With PROVE_LOCKING feature, the kernel size could
> +	 grow beyond this limit and causing system bootup issues. With
> +	 this option, kernel limits the size of the entries of lock_chains,
> +	 stack_trace etc. to debug PROVE_LOCKING so that kernel size fits
> +	 in 32MB. This is only visible for SPARC.

Since this is only relevant for sparc, and for sparc this is "select"ed,
then there is limited/no gain having this as a visible menu config option.

How about adding just a simple non-visible config symbol:

config PROVE_LOCKING_SMALL
	bool

The nice help text can be added to the H file, and the select
can be move to the sparc/Kconfig file where it really belongs.

	Sam

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#1491843

FromPeter Zijlstra <peterz@infradead.org>
Date2016-09-27 13:50 +0200
Message-ID<slZ3z-zK-13@gated-at.bofh.it>
In reply to#1491682
On Tue, Sep 27, 2016 at 06:46:25AM +0200, Sam Ravnborg wrote:
> Since this is only relevant for sparc, and for sparc this is "select"ed,
> then there is limited/no gain having this as a visible menu config option.
> 
> How about adding just a simple non-visible config symbol:
> 
> config PROVE_LOCKING_SMALL
> 	bool
> 
> The nice help text can be added to the H file, and the select
> can be move to the sparc/Kconfig file where it really belongs.

Yes, this should not be user selectable. I don't mind the help being
here though.

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#1491971

FromBabu Moger <babu.moger@oracle.com>
Date2016-09-27 17:00 +0200
Message-ID<sm21s-2jb-35@gated-at.bofh.it>
In reply to#1491843
On 9/27/2016 6:40 AM, Peter Zijlstra wrote:
> On Tue, Sep 27, 2016 at 06:46:25AM +0200, Sam Ravnborg wrote:
>> Since this is only relevant for sparc, and for sparc this is "select"ed,
>> then there is limited/no gain having this as a visible menu config option.
>>
>> How about adding just a simple non-visible config symbol:
>>
>> config PROVE_LOCKING_SMALL
>> 	bool
>>
>> The nice help text can be added to the H file, and the select
>> can be move to the sparc/Kconfig file where it really belongs.
> Yes, this should not be user selectable. I don't mind the help being
> here though.
  How about this?
  Moved everything to arch/sparc/Kconfig.debug. It may be not useful to 
have help in
config file as it is not visible. Lets have some explanation in .h file.
I will send v3 version if you all agree.
=====================================
diff --git a/arch/sparc/Kconfig.debug b/arch/sparc/Kconfig.debug
index 6db35fb..67e58a1 100644
--- a/arch/sparc/Kconfig.debug
+++ b/arch/sparc/Kconfig.debug
@@ -21,4 +21,9 @@ config FRAME_POINTER
         depends on MCOUNT
         default y

+config PROVE_LOCKING_SMALL
+       bool
+       depends on PROVE_LOCKING && SPARC
+       default y
+
  endmenu

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#1491998

FromSam Ravnborg <sam@ravnborg.org>
Date2016-09-27 17:50 +0200
Message-ID<sm2NQ-2OB-27@gated-at.bofh.it>
In reply to#1491971
On Tue, Sep 27, 2016 at 09:51:40AM -0500, Babu Moger wrote:
> 
> On 9/27/2016 6:40 AM, Peter Zijlstra wrote:
> >On Tue, Sep 27, 2016 at 06:46:25AM +0200, Sam Ravnborg wrote:
> >>Since this is only relevant for sparc, and for sparc this is "select"ed,
> >>then there is limited/no gain having this as a visible menu config option.
> >>
> >>How about adding just a simple non-visible config symbol:
> >>
> >>config PROVE_LOCKING_SMALL
> >>	bool
> >>
> >>The nice help text can be added to the H file, and the select
> >>can be move to the sparc/Kconfig file where it really belongs.
> >Yes, this should not be user selectable. I don't mind the help being
> >here though.
>  How about this?
>  Moved everything to arch/sparc/Kconfig.debug. It may be not useful
> to have help in
> config file as it is not visible. Lets have some explanation in .h file.
> I will send v3 version if you all agree.
> =====================================
> diff --git a/arch/sparc/Kconfig.debug b/arch/sparc/Kconfig.debug
> index 6db35fb..67e58a1 100644
> --- a/arch/sparc/Kconfig.debug
> +++ b/arch/sparc/Kconfig.debug
> @@ -21,4 +21,9 @@ config FRAME_POINTER
>         depends on MCOUNT
>         default y
> 
> +config PROVE_LOCKING_SMALL
> +       bool
> +       depends on PROVE_LOCKING && SPARC
> +       default y
> +
>  endmenu

The idea is to have the SPAC specific stuff in arch/sparc/Kconfig,
and not scattered in Kconfig files all over the tree.

Therefore drop the "depends".

In sparc/Kconfig you then just do:

config SPARC
	select PROVE_LOCKING_SMALL if PROVE_LOCKING

The if part is likely not needed as PROVE_LOCKING_SMALL will be ignored
unless PROVE_LOCKING is enabled.

	Sam

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#1492013

FromBabu Moger <babu.moger@oracle.com>
Date2016-09-27 18:30 +0200
Message-ID<sm3qx-3lO-7@gated-at.bofh.it>
In reply to#1491998

On 9/27/2016 10:43 AM, Sam Ravnborg wrote:
> On Tue, Sep 27, 2016 at 09:51:40AM -0500, Babu Moger wrote:
>> On 9/27/2016 6:40 AM, Peter Zijlstra wrote:
>>> On Tue, Sep 27, 2016 at 06:46:25AM +0200, Sam Ravnborg wrote:
>>>> Since this is only relevant for sparc, and for sparc this is "select"ed,
>>>> then there is limited/no gain having this as a visible menu config option.
>>>>
>>>> How about adding just a simple non-visible config symbol:
>>>>
>>>> config PROVE_LOCKING_SMALL
>>>> 	bool
>>>>
>>>> The nice help text can be added to the H file, and the select
>>>> can be move to the sparc/Kconfig file where it really belongs.
>>> Yes, this should not be user selectable. I don't mind the help being
>>> here though.
>>   How about this?
>>   Moved everything to arch/sparc/Kconfig.debug. It may be not useful
>> to have help in
>> config file as it is not visible. Lets have some explanation in .h file.
>> I will send v3 version if you all agree.
>> =====================================
>> diff --git a/arch/sparc/Kconfig.debug b/arch/sparc/Kconfig.debug
>> index 6db35fb..67e58a1 100644
>> --- a/arch/sparc/Kconfig.debug
>> +++ b/arch/sparc/Kconfig.debug
>> @@ -21,4 +21,9 @@ config FRAME_POINTER
>>          depends on MCOUNT
>>          default y
>>
>> +config PROVE_LOCKING_SMALL
>> +       bool
>> +       depends on PROVE_LOCKING && SPARC
>> +       default y
>> +
>>   endmenu
> The idea is to have the SPAC specific stuff in arch/sparc/Kconfig,
> and not scattered in Kconfig files all over the tree.
>
> Therefore drop the "depends".
>
> In sparc/Kconfig you then just do:
>
> config SPARC
> 	select PROVE_LOCKING_SMALL if PROVE_LOCKING
>
> The if part is likely not needed as PROVE_LOCKING_SMALL will be ignored
> unless PROVE_LOCKING is enabled.
  Sure. thanks.  Here it is below. I will re-post v3.


diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index cde1a62..353731f 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -43,6 +43,7 @@ config SPARC
         select ODD_RT_SIGACTION
         select OLD_SIGSUSPEND
         select ARCH_HAS_SG_CHAIN
+       select PROVE_LOCKING_SMALL if PROVE_LOCKING

  config SPARC32
         def_bool !64BIT
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index ba2b0c8..3ba1665 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1008,6 +1008,9 @@ config PROVE_LOCKING

          For more details, see Documentation/locking/lockdep-design.txt.

+config PROVE_LOCKING_SMALL
+       bool
+
  config LOCKDEP
         bool
         depends on DEBUG_KERNEL && TRACE_IRQFLAGS_SUPPORT && 
STACKTRACE_SUPPORT && LOCKDEP_SUPPORT




> 	Sam

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