On Mon, 13 May 2019 15:43:08 +0300 Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> wrote:
> > +/*
> > + * Returns the number of bytes in this potentially compound page.
> > + * Must be called with the head page, not a tail page.
> > + */
> > +static inline unsigned long page_size(struct page *page)
> > +{
>
> Maybe we should underline commented head page limitation with VM_BUG_ON()?
VM_WARN_ONCE() if poss, please.
The code bloatage from that is likely to be distressing. Perhaps
adding an out-of-line compound_order_head_only() for this reason would
help. In which case, just uninline the whole thing...
> + return (unsigned long)PAGE_SIZE << compound_order(page);
> + }
Also, I suspect the cast here is unneeded. Architectures used to
differe in the type of PAGE_SIZE but please tell me that's been fixed
for a lomng time...
