On Tue, 05 Feb 2013 11:09:27 +0800
Lin Feng <linfeng@xxxxxxxxxxxxxx> wrote:
> >
> >> struct kvec;
> >> int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
> >> struct page **pages);
> >> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> >> index 73b64a3..5db811e 100644
> >> --- a/include/linux/mmzone.h
> >> +++ b/include/linux/mmzone.h
> >> @@ -838,6 +838,10 @@ static inline int is_normal_idx(enum zone_type idx)
> >> return (idx == ZONE_NORMAL);
> >> }
> >>
> >> +static inline int is_movable(struct zone *zone)
> >> +{
> >> + return zone == zone->zone_pgdat->node_zones + ZONE_MOVABLE;
> >> +}
> >
> > A better name would be zone_is_movable(). We haven't been very
> > consistent about this in mmzone.h, but zone_is_foo() is pretty common.
> >
> Yes, zone_is_xxx() should be a better name, but there are some analogous
> definition like is_dma32() and is_normal() etc, if we only use zone_is_movable()
> for movable zone it will break such naming rules.
> Should we update other ones in a separate patch later or just keep the old style?
I do think the old names were poorly chosen. Yes, we could fix them up
sometime but it's hardly a pressing issue.
> > And a neater implementation would be
> >
> > return zone_idx(zone) == ZONE_MOVABLE;
> >
> OK. After your change, should we also update for other ones such as is_normal()..?
Sure.
From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: include-linux-mmzoneh-cleanups-fix
use zone_idx() some more, further simplify is_highmem()
Cc: Lin Feng <linfeng@xxxxxxxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)
diff -puN include/linux/mmzone.h~include-linux-mmzoneh-cleanups-fix include/linux/mmzone.h
--- a/include/linux/mmzone.h~include-linux-mmzoneh-cleanups-fix
+++ a/include/linux/mmzone.h
@@ -859,25 +859,18 @@ static inline int is_normal_idx(enum zon
*/
static inline int is_highmem(struct zone *zone)
{
-#ifdef CONFIG_HIGHMEM
- enum zone_type idx = zone_idx(zone);
-
- return idx == ZONE_HIGHMEM ||
- (idx == ZONE_MOVABLE && zone_movable_is_highmem());
-#else
- return 0;
-#endif
+ return is_highmem_idx(zone_idx(zone));
}
static inline int is_normal(struct zone *zone)
{
- return zone == zone->zone_pgdat->node_zones + ZONE_NORMAL;
+ return zone_idx(zone) == ZONE_NORMAL;
}
static inline int is_dma32(struct zone *zone)
{
#ifdef CONFIG_ZONE_DMA32
- return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
+ return zone_idx(zone) == ZONE_DMA32;
#else
return 0;
#endif
@@ -886,7 +879,7 @@ static inline int is_dma32(struct zone *
static inline int is_dma(struct zone *zone)
{
#ifdef CONFIG_ZONE_DMA
- return zone == zone->zone_pgdat->node_zones + ZONE_DMA;
+ return zone_idx(zone) == ZONE_DMA;
#else
return 0;
#endif
_
> >> + /* All pages are non movable, we are done :) */
> >> + if (i == ret && list_empty(&pagelist))
> >> + return ret;
> >> +
> >> +put_page:
> >> + /* Undo the effects of former get_user_pages(), we won't pin anything */
> >> + for (i = 0; i < ret; i++)
> >> + put_page(pages[i]);
> >> +
> >> + if (migrate_pre_flag && !isolate_err) {
> >> + ret = migrate_pages(&pagelist, alloc_migrate_target, 1,
> >> + false, MIGRATE_SYNC, MR_SYSCALL);
> >> + /* Steal pages from non-movable zone successfully? */
> >> + if (!ret)
> >> + goto retry;
> >
> > This is buggy. migrate_pages() doesn't empty its `from' argument, so
> > page_list must be reinitialised here (or, better, at the start of the loop).
> migrate_pages()
> list_for_each_entry_safe()
> unmap_and_move()
> if (rc != -EAGAIN) {
> list_del(&page->lru);
> }
ah, OK, there it is.
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