Messages in this thread | | | Date | Thu, 27 Feb 2014 17:34:05 +0100 | From | Oleg Nesterov <> | Subject | Re: + mm-revert-thp-make-madv_hugepage-check-for-mm-def_flags.patch added to -mm tree |
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On 02/26, Paolo Bonzini wrote: > > > +#ifdef CONFIG_S390 > > + /* > > + * MADV_HUGEPAGE is broken after s390_enable_sie(), qemu > > + * blindly does madvise(MADV_HUGEPAGE) for for all kvm pages > > + * and expects it must fail on s390. Avoid a possible SIGSEGV > > + * until qemu is changed. > > + */ > > + if (mm_has_pgste(vma->vm_mm)) > > + return -EINVAL; > > +#endif > > The comment is not quite true. QEMU doesn't expect that the madvise fails.
Yes, sorry. I didn't mean "it expects -EINVAL".
> It simply expects that the madvise doesn't cause SIGSEGVs or later > malfunctioning, because (quoting tha man page) madvise "does not influence > the semantics of the application".
Yes, I understand. But currently this means "MADV_HUGEPAGE should not actually work", this is what I tried to say.
> There's nothing to fix in QEMU,
I was going to argue, but this is probably true too.
In short: I agree with any comment ;)
Oleg.
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