Re: [PATCH v18 10/10] virtio-balloon: don't report free pages when page poisoning is enabled

[Wei Wang <wei.w.wang@intel.com>]

On 11/30/2017 06:45 PM, Tetsuo Handa wrote:
> Wei Wang wrote:
> > @@ -652,7 +652,9 @@ static void report_free_page(struct work_struct *work)
> >   	/* Start by sending the obtained cmd id to the host with an outbuf */
> >   	send_one_desc(vb, vb->free_page_vq, virt_to_phys(&vb->start_cmd_id),
> >   		      sizeof(uint32_t), false, true, false);
> > -	walk_free_mem_block(vb, 0, &virtio_balloon_send_free_pages);
> > +	if (!(page_poisoning_enabled() &&
> > +	    !IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY)))
> I think that checking IS_ENABLED() before checking page_poisoning_enabled()
> would generate better code, for IS_ENABLED() is build-time constant while
> page_poisoning_enabled() is a function which the compiler assumes that we
> need to call page_poisoning_enabled() even if IS_ENABLED() is known to be 0.
>
> 	if (IS_ENABLED(CONFIG_PAGE_POISONING_NO_SANITY) ||
> 	    !page_poisoning_enabled())

Agree, thanks.

Best,
Wei