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    SubjectRe: [PATCH v2 3/3] KVM: remove dummy pages
    On 07/26/2012 06:58 AM, Xiao Guangrong wrote:
    > Currently, kvm allocates some pages and use them as error indicators,
    > it wastes memory and is not good for scalability
    >
    > Base on Avi's suggestion, we use the error codes instead of these pages
    > to indicate the error conditions
    >
    >
    > +static pfn_t get_bad_pfn(void)
    > +{
    > + return -ENOENT;
    > +}
    > +
    > +pfn_t get_fault_pfn(void)
    > +{
    > + return -EFAULT;
    > +}
    > +EXPORT_SYMBOL_GPL(get_fault_pfn);
    > +
    > +static pfn_t get_hwpoison_pfn(void)
    > +{
    > + return -EHWPOISON;
    > +}
    > +

    Would be better as #defines

    > int is_hwpoison_pfn(pfn_t pfn)
    > {
    > - return pfn == hwpoison_pfn;
    > + return pfn == -EHWPOISON;
    > }
    > EXPORT_SYMBOL_GPL(is_hwpoison_pfn);
    >
    > int is_noslot_pfn(pfn_t pfn)
    > {
    > - return pfn == bad_pfn;
    > + return pfn == -ENOENT;
    > }
    > EXPORT_SYMBOL_GPL(is_noslot_pfn);
    >
    > int is_invalid_pfn(pfn_t pfn)
    > {
    > - return pfn == hwpoison_pfn || pfn == fault_pfn;
    > + return !is_noslot_pfn(pfn) && is_error_pfn(pfn);
    > }
    > EXPORT_SYMBOL_GPL(is_invalid_pfn);
    >

    So is_*_pfn() could go away and be replaced by ==.

    >
    > EXPORT_SYMBOL_GPL(gfn_to_page);
    >
    > void kvm_release_page_clean(struct page *page)
    > {
    > - kvm_release_pfn_clean(page_to_pfn(page));
    > + if (!is_error_page(page))
    > + kvm_release_pfn_clean(page_to_pfn(page));
    > }
    > EXPORT_SYMBOL_GPL(kvm_release_page_clean);

    Note, we can remove calls to kvm_release_page_clean() from error paths
    now, so in the future we can drop the test.

    Since my comments are better done as a separate patch, I applied all
    three patches. Thanks!

    --
    error compiling committee.c: too many arguments to function




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