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[PATCH 1/2] perf_event: remove unused DEBUG_PERF_USE_VMALLOC

Started byKim Phillips <kim.phillips@arm.com>
First post2016-08-30 21:10 +0200
Last post2016-08-31 09:10 +0200
Articles 2 — 2 participants

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  [PATCH 1/2] perf_event: remove unused DEBUG_PERF_USE_VMALLOC Kim Phillips <kim.phillips@arm.com> - 2016-08-30 21:10 +0200
    Re: [PATCH 1/2] perf_event: remove unused DEBUG_PERF_USE_VMALLOC Peter Zijlstra <peterz@infradead.org> - 2016-08-31 09:10 +0200

#1472788 — [PATCH 1/2] perf_event: remove unused DEBUG_PERF_USE_VMALLOC

FromKim Phillips <kim.phillips@arm.com>
Date2016-08-30 21:10 +0200
Subject[PATCH 1/2] perf_event: remove unused DEBUG_PERF_USE_VMALLOC
Message-ID<sbWA2-tT-35@gated-at.bofh.it>
This 'DEBUG'-prefixed version of PERF_USE_VMALLOC is not used anywhere.
It appears to be leftovers from commit 906010b "perf_event: Provide
vmalloc() based mmap() backing" that introduced it.

Not sure what commit cb30711 "perf_event: Don't allow vmalloc() backed
perf on powerpc" was trying to do with it either.

Signed-off-by: Kim Phillips <kim.phillips@arm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Ellerman <mpe@ellerman.id.au>
---
 init/Kconfig | 13 -------------
 1 file changed, 13 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index cac3f09..934a61f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1707,19 +1707,6 @@ config PERF_EVENTS
 
 	  Say Y if unsure.
 
-config DEBUG_PERF_USE_VMALLOC
-	default n
-	bool "Debug: use vmalloc to back perf mmap() buffers"
-	depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
-	select PERF_USE_VMALLOC
-	help
-	 Use vmalloc memory to back perf mmap() buffers.
-
-	 Mostly useful for debugging the vmalloc code on platforms
-	 that don't require it.
-
-	 Say N if unsure.
-
 endmenu
 
 config VM_EVENT_COUNTERS
-- 
2.9.3

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#1473072

FromPeter Zijlstra <peterz@infradead.org>
Date2016-08-31 09:10 +0200
Message-ID<sc7OO-7Io-5@gated-at.bofh.it>
In reply to#1472788
On Tue, Aug 30, 2016 at 02:08:34PM -0500, Kim Phillips wrote:
> This 'DEBUG'-prefixed version of PERF_USE_VMALLOC is not used anywhere.
> It appears to be leftovers from commit 906010b "perf_event: Provide
> vmalloc() based mmap() backing" that introduced it.
> 
> Not sure what commit cb30711 "perf_event: Don't allow vmalloc() backed
> perf on powerpc" was trying to do with it either.
> 
> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> ---
>  init/Kconfig | 13 -------------
>  1 file changed, 13 deletions(-)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index cac3f09..934a61f 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -1707,19 +1707,6 @@ config PERF_EVENTS
>  
>  	  Say Y if unsure.
>  
> -config DEBUG_PERF_USE_VMALLOC
> -	default n
> -	bool "Debug: use vmalloc to back perf mmap() buffers"
> -	depends on PERF_EVENTS && DEBUG_KERNEL && !PPC
> -	select PERF_USE_VMALLOC

^^^^^


It forces the use of vmalloc backed pages for the ring-buffer so that we
can test that code on x86, which otherwise doesn't use it.

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