On Thu, 3 Mar 2016 16:43:49 +0900 Joonsoo Kim <js1...@gmail.com> wrote:
> > Acked-by: Vlastimil Babka <vba...@suse.cz>
> >
> >> +config DEBUG_PAGE_REF
> >> + bool "Enable tracepoint to track down page reference manipulation"
> >> + depends on DEBUG_KERNEL
> >> + depends on TRACEPOINTS
> >> + ---help---
> >> + This is the feature to add tracepoint for tracking down page
> >> reference
> >> + manipulation. This tracking is useful to diagnosis functional
> >> failure
> >> + due to migration failure caused by page reference mismatch. Be
> >
> >
> > OK.
> >
> >> + careful to turn on this feature because it could bloat some
> >> kernel
> >> + text. In my configuration, it bloats 30 KB. Although kernel text
> >> will
> >> + be bloated, there would be no runtime performance overhead if
> >> + tracepoint isn't enabled thanks to jump label.
> >
> >
> > I would just write something like:
> >
> > Enabling this feature adds about 30 KB to the kernel code, but runtime
> > performance overhead is virtually none until the tracepoints are actually
> > enabled.
>
> Okay, better!
> Andrew, do you want fixup patch from me or could you simply handle it?
>
This?
---
a/mm/Kconfig.debug~mm-page_ref-add-tracepoint-to-track-down-page-reference-manipulation-fix-3-fix
+++ a/mm/Kconfig.debug
@@ -82,10 +82,9 @@ config DEBUG_PAGE_REF
depends on DEBUG_KERNEL
depends on TRACEPOINTS
---help---
- This is the feature to add tracepoint for tracking down page reference
- manipulation. This tracking is useful to diagnosis functional failure
- due to migration failure caused by page reference mismatch. Be
- careful to turn on this feature because it could bloat some kernel
- text. In my configuration, it bloats 30 KB. Although kernel text will
- be bloated, there would be no runtime performance overhead if
- tracepoint isn't enabled thanks to jump label.
+ This is a feature to add tracepoint for tracking down page reference
+ manipulation. This tracking is useful to diagnose functional failure
+ due to migration failures caused by page reference mismatches. Be
+ careful when enabling this feature because it adds about 30 KB to the
+ kernel code. However the runtime performance overhead is virtually
+ nil until the tracepoints are actually enabled.
_
