+static inline int
+should_alloc_retry(gfp_t gfp_mask, unsigned int order,
+ unsigned long pages_reclaimed)
+{
+ /* Do not loop if specifically requested */
+ if (gfp_mask & __GFP_NORETRY)
+ return 0;
+
+ /*
+ * In this implementation, order <= PAGE_ALLOC_COSTLY_ORDER
+ * means __GFP_NOFAIL, but that may not be true in other
+ * implementations.
+ */
+ if (order <= PAGE_ALLOC_COSTLY_ORDER)
+ return 1;
+
+ /*
+ * For order > PAGE_ALLOC_COSTLY_ORDER, if __GFP_REPEAT is
+ * specified, then we retry until we no longer reclaim any pages
+ * (above), or we've reclaimed an order of pages at least as
+ * large as the allocation's order. In both cases, if the
+ * allocation still fails, we stop retrying.
+ */
+ if (gfp_mask & __GFP_REPEAT && pages_reclaimed < (1 << order))
+ return 1;
+
+ /*
+ * Don't let big-order allocations loop unless the caller
+ * explicitly requests that.
+ */
+ if (gfp_mask & __GFP_NOFAIL)
+ return 1;
+
+ return 0;
+}
+
+static inline struct page *
+__alloc_pages_may_oom(gfp_t gfp_mask, unsigned int order,
+ struct zonelist *zonelist, enum zone_type high_zoneidx,
+ nodemask_t *nodemask, struct zone *preferred_zone,
+ int migratetype)
+{
+ struct page *page;
+
+ /* Acquire the OOM killer lock for the zones in zonelist */
+ if (!try_set_zone_oom(zonelist, gfp_mask)) {
+ schedule_timeout_uninterruptible(1);
+ return NULL;
+ }
+
+ /*
+ * Go through the zonelist yet one more time, keep very high watermark
+ * here, this is only to catch a parallel oom killing, we must fail if
+ * we're still under heavy pressure.
+ */
+ page = get_page_from_freelist(gfp_mask|__GFP_HARDWALL, nodemask,
+ order, zonelist, high_zoneidx,
+ ALLOC_WMARK_HIGH|ALLOC_CPUSET,
+ preferred_zone, migratetype);
+ if (page)
+ goto out;
+
+ /* The OOM killer will not help higher order allocs */
+ if (order > PAGE_ALLOC_COSTLY_ORDER && !(gfp_mask & __GFP_NOFAIL))
+ goto out;
+
+ /* Exhausted what can be done so it's blamo time */
+ out_of_memory(zonelist, gfp_mask, order);
+
+out:
+ clear_zonelist_oom(zonelist, gfp_mask);
+ return page;
+}
+
+/* The really slow allocator path where we enter direct reclaim */
+static inline struct page *
+__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
+ struct zonelist *zonelist, enum zone_type high_zoneidx,
+ nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
+ int migratetype, unsigned long *did_some_progress)
+{
+ struct page *page = NULL;
+ struct reclaim_state reclaim_state;
+ struct task_struct *p = current;
+
+ cond_resched();
+
+ /* We now go into synchronous reclaim */
+ cpuset_memory_pressure_bump();
+ p->flags |= PF_MEMALLOC;
+ lockdep_set_current_reclaim_state(gfp_mask);
+ reclaim_state.reclaimed_slab = 0;
+ p->reclaim_state = &reclaim_state;
+
+ *did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
+
+ p->reclaim_state = NULL;
+ lockdep_clear_current_reclaim_state();
+ p->flags &= ~PF_MEMALLOC;
+
+ cond_resched();
+
+ if (order != 0)
+ drain_all_pages();
+
+ if (likely(*did_some_progress))
+ page = get_page_from_freelist(gfp_mask, nodemask, order,
+ zonelist, high_zoneidx,
+ alloc_flags, preferred_zone,
+ migratetype);
+ return page;
+}
+