On Thu, 3 Mar 2016 16:43:49 +0900 Joonsoo Kim <js1304@xxxxxxxxx> wrote: > > Acked-by: Vlastimil Babka <vbabka@xxxxxxx> > > > >> +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. _ -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
