Messages in this thread | | | Date | Tue, 24 Apr 2018 11:50:30 -0400 (EDT) | From | Mikulas Patocka <> | Subject | Re: [PATCH v3] kvmalloc: always use vmalloc if CONFIG_DEBUG_SG |
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On Tue, 24 Apr 2018, Michal Hocko wrote:
> On Mon 23-04-18 20:06:16, Mikulas Patocka wrote: > [...] > > @@ -404,6 +405,12 @@ void *kvmalloc_node(size_t size, gfp_t f > > */ > > WARN_ON_ONCE((flags & GFP_KERNEL) != GFP_KERNEL); > > > > +#ifdef CONFIG_DEBUG_SG > > + /* Catch bugs when the caller uses DMA API on the result of kvmalloc. */ > > + if (!(prandom_u32_max(2) & 1)) > > + goto do_vmalloc; > > +#endif > > I really do not think there is anything DEBUG_SG specific here. Why you > simply do not follow should_failslab path or even reuse the function?
CONFIG_DEBUG_SG is enabled by default in RHEL and Fedora debug kernel (if you don't like CONFIG_DEBUG_SG, pick any other option that is enabled there).
Fail-injection framework is if off by default and it must be explicitly enabled and configured by the user - and most users won't enable it.
Mikulas
> > + > > /* > > * We want to attempt a large physically contiguous block first because > > * it is less likely to fragment multiple larger blocks and therefore > > @@ -427,6 +434,9 @@ void *kvmalloc_node(size_t size, gfp_t f > > if (ret || size <= PAGE_SIZE) > > return ret; > > > > +#ifdef CONFIG_DEBUG_SG > > +do_vmalloc: > > +#endif > > return __vmalloc_node_flags_caller(size, node, flags, > > __builtin_return_address(0)); > > } > > -- > Michal Hocko > SUSE Labs >
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