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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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