On Mon, Aug 19, 2019 at 9:50 PM Vlastimil Babka <vbabka@xxxxxxx> wrote:
>
> On 8/17/19 12:51 PM, Pengfei Li wrote:
> > This patch cleans up the if(page).
> >
> > No functional change.
> >
> > Signed-off-by: Pengfei Li <lpf.vector@xxxxxxxxx>
>
> I don't see much benefit here. The indentation wasn't that bad that it
> had to be reduced using goto. But the patch is not incorrect so I'm not
> NACKing.
>
Thanks for your review and comments.
This patch reduces the number of times the if(page)
(as the compiler does), and the downside is that there is a goto.
If this improves readability, accept it. Otherwise, leave it as it is.
Thanks again.
---
Pengfei
> > ---
> > mm/page_alloc.c | 28 ++++++++++++++++------------
> > 1 file changed, 16 insertions(+), 12 deletions(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index 272c6de1bf4e..51f056ac09f5 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -3890,6 +3890,7 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
> > enum compact_priority prio, enum compact_result *compact_result)
> > {
> > struct page *page = NULL;
> > + struct zone *zone;
> > unsigned long pflags;
> > unsigned int noreclaim_flag;
> >
> > @@ -3911,23 +3912,26 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
> > */
> > count_vm_event(COMPACTSTALL);
> >
> > - /* Prep a captured page if available */
> > - if (page)
> > + if (page) {
> > + /* Prep a captured page if available */
> > prep_new_page(page, order, gfp_mask, alloc_flags);
> > -
> > - /* Try get a page from the freelist if available */
> > - if (!page)
> > + } else {
> > + /* Try get a page from the freelist if available */
> > page = get_page_from_freelist(gfp_mask, order, alloc_flags, ac);
> >
> > - if (page) {
> > - struct zone *zone = page_zone(page);
> > -
> > - zone->compact_blockskip_flush = false;
> > - compaction_defer_reset(zone, order, true);
> > - count_vm_event(COMPACTSUCCESS);
> > - return page;
> > + if (!page)
> > + goto failed;
> > }
> >
> > + zone = page_zone(page);
> > + zone->compact_blockskip_flush = false;
> > + compaction_defer_reset(zone, order, true);
> > +
> > + count_vm_event(COMPACTSUCCESS);
> > +
> > + return page;
> > +
> > +failed:
> > /*
> > * It's bad if compaction run occurs and fails. The most likely reason
> > * is that pages exist, but not enough to satisfy watermarks.
> >
>
