Re: [PATCH 1/2] mm: swap: make page_evictable() inline

[Yang Shi]

On 3/14/20 9:01 AM, Matthew Wilcox wrote:
> On Sat, Mar 14, 2020 at 02:34:35AM +0800, Yang Shi wrote:
> > -extern int page_evictable(struct page *page);
> > +/*
> This seems to be in kernel-doc format already; could you add the extra
> '*' so it is added to the fine documentation?

Yes, sure.

> > + * page_evictable - test whether a page is evictable
> > + * @page: the page to test
> > + *
> > + * Test whether page is evictable--i.e., should be placed on active/inactive
> > + * lists vs unevictable list.
> > + *
> > + * Reasons page might not be evictable:
> > + * (1) page's mapping marked unevictable
> > + * (2) page is part of an mlocked VMA
> > + *
> > + */
> > +static inline int page_evictable(struct page *page)
> > +{
> > +	int ret;
> > +
> > +	/* Prevent address_space of inode and swap cache from being freed */
> > +	rcu_read_lock();
> > +	ret = !mapping_unevictable(page_mapping(page)) && !PageMlocked(page);
> > +	rcu_read_unlock();
> > +	return ret;
> > +}
> This seems like it should return bool ... that might even lead to code
> generation improvement.

Thanks for catching this. It looks mapping_unevictable() needs to be 
converted to bool as well.