Messages in this thread | | | Date | Fri, 24 Apr 2015 14:38:44 -0700 (PDT) | From | David Rientjes <> | Subject | Re: [PATCH 2/2] mm/page_alloc.c: add config option to sanitize freed pages |
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On Fri, 24 Apr 2015, Anisse Astier wrote:
> diff --git a/mm/Kconfig b/mm/Kconfig > index 390214d..cb2df5f 100644 > --- a/mm/Kconfig > +++ b/mm/Kconfig > @@ -635,3 +635,15 @@ config MAX_STACK_SIZE_MB > changed to a smaller value in which case that is used. > > A sane initial value is 80 MB. > + > +config SANITIZE_FREED_PAGES > + bool "Sanitize memory pages after free" > + default n > + help > + This option is used to make sure all pages freed are zeroed. This is > + quite low-level and doesn't handle your slab buffers. > + It has various applications, from preventing some info leaks to > + helping kernel same-page merging in virtualised environments. > + Depending on your workload, it will reduce performance of about 3%. > + > + If unsure, say N.
Objection to allowing this without first enabling some other DEBUG config option, it should never be a standalone option, but also to pretending to have any insight into what the performance degredation of it will be. On my systems, this would be _massive_.
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