On Fri, Feb 28, 2014 at 03:15:01PM +0100, Vlastimil Babka wrote: > This patch complements the addition of get_pageblock_migratetype_nolock() for > the case where is_migrate_isolate_page() cannot be called with zone->lock > held. > A race with set_pageblock_migratetype() may be detected, in which case a > caller > supplied argument is returned. > > Signed-off-by: Vlastimil Babka <vba...@suse.cz> > --- > include/linux/page-isolation.h | 24 ++++++++++++++++++++++++ > mm/hugetlb.c | 2 +- > 2 files changed, 25 insertions(+), 1 deletion(-) > > diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h > index 3fff8e7..f7bd491 100644 > --- a/include/linux/page-isolation.h > +++ b/include/linux/page-isolation.h > @@ -2,10 +2,30 @@ > #define __LINUX_PAGEISOLATION_H > > #ifdef CONFIG_MEMORY_ISOLATION > +/* > + * Should be called only with zone->lock held. In cases where locking > overhead > + * is undesirable, consider the _nolock version. > + */ > static inline bool is_migrate_isolate_page(struct page *page) > { > return get_pageblock_migratetype(page) == MIGRATE_ISOLATE; > } > +/* > + * When called without zone->lock held, a race with set_pageblock_migratetype > + * may result in bogus values. The race may be detected, in which case the > + * value of race_fallback argument is returned. For details, see > + * get_pageblock_migratetype_nolock(). > + */ > +static inline bool is_migrate_isolate_page_nolock(struct page *page, > + bool race_fallback) > +{ > + int migratetype = get_pageblock_migratetype_nolock(page, MIGRATE_TYPES); > + > + if (unlikely(migratetype == MIGRATE_TYPES)) > + return race_fallback; > + > + return migratetype == MIGRATE_ISOLATE; > +} > static inline bool is_migrate_isolate(int migratetype) > { > return migratetype == MIGRATE_ISOLATE; > @@ -15,6 +35,10 @@ static inline bool is_migrate_isolate_page(struct page > *page) > { > return false; > } > +static inline bool is_migrate_isolate_page_nolock(struct page *page) > +{ > + return false; > +} > static inline bool is_migrate_isolate(int migratetype) > { > return false;
Nitpick. You need race_fallback parameter for is_migrate_isolate_page_nolock(). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/