Re: [PATCH -mm] vmscan: merge duplicate code in shrink_active_list()

[Minchan Kim <minchan.kim@gmail.com>]

On Tue, 12 May 2009 19:48:07 +0800
Wu Fengguang <fengguang.wu@intel.com> wrote:

> On Tue, May 12, 2009 at 03:26:33PM +0800, Minchan Kim wrote:
> > On Tue, 12 May 2009 10:53:19 +0800
> > Wu Fengguang <fengguang.wu@intel.com> wrote:
> > 
> > > The "move pages to active list" and "move pages to inactive list"
> > > code blocks are mostly identical and can be served by a function.
> > > 
> > > Thanks to Andrew Morton for pointing this out.
> > > 
> > > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> > > ---
> > >  mm/vmscan.c |   84 ++++++++++++++++++++------------------------------
> > >  1 file changed, 35 insertions(+), 49 deletions(-)
> > > 
> > > --- linux.orig/mm/vmscan.c
> > > +++ linux/mm/vmscan.c
> > > @@ -1225,6 +1225,36 @@ static inline void note_zone_scanning_pr
> > >   * But we had to alter page->flags anyway.
> > >   */
> > >  
> > > +void move_active_pages_to_lru(enum lru_list lru, struct list_head *list)
> > > +{
> > > +	unsigned long pgmoved = 0;
> > > +
> > > +	while (!list_empty(&list)) {
> > > +		page = lru_to_page(&list);
> > > +		prefetchw_prev_lru_page(page, &list, flags);
> > > +
> > > +		VM_BUG_ON(PageLRU(page));
> > > +		SetPageLRU(page);
> > > +
> > > +		VM_BUG_ON(!PageActive(page));
> > > +		if (lru < LRU_ACTIVE)
> > > +			ClearPageActive(page);
> > 
> > Arithmetic on the LRU list is not good code for redability, I think. 
> > How about adding comment? 
> > 
> > if (lru < LRU_ACTIVE) /* In case of moving from active list to inactive */
> > 
> > Ignore me if you think this is trivial. 
> 
> Good suggestion. Or this simple one: "we are de-activating"?
> 

Looks good to me :)

> Thanks,
> Fengguang


-- 
Kinds Regards
Minchan Kim