@@ -1050,17 +1120,42 @@ static void scrub_free_pages(unsigned int node)
scrub_one_page(&pg[i]);
pg[i].count_info &= ~PGC_need_scrub;
node_need_scrub[node]--;
+ cnt += 100; /* scrubbed pages add heavier weight. */
+ }
+ else
+ cnt++;
+
+ /*
+ * Scrub a few (8) pages before becoming eligible for
+ * preemption. But also count non-scrubbing loop iterations
+ * so that we don't get stuck here with an almost clean
+ * heap.
+ */
+ if ( cnt > 800 && softirq_pending(cpu) )
+ {
+ preempt = true;
+ break;
}
}
- page_list_del(pg, &heap(node, zone, order));
- page_list_add_scrub(pg, node, zone, order, INVALID_DIRTY_IDX);
+ if ( i >= (1U << order) - 1 )
+ {
+ page_list_del(pg, &heap(node, zone, order));
+ page_list_add_scrub(pg, node, zone, order,
INVALID_DIRTY_IDX);
+ }
+ else
+ pg->u.free.first_dirty = i + 1;
- if ( node_need_scrub[node] == 0 )
- return;
+ if ( preempt || (node_need_scrub[node] == 0) )
+ goto out;
}
} while ( order-- != 0 );
}
+
+ out:
+ spin_unlock(&heap_lock);
+ node_clear(node, node_scrubbing);
+ return softirq_pending(cpu) || (node_to_scrub(false) != NUMA_NO_NODE);
While I can see why you use it here, the softirq_pending() looks sort of
misplaced: While invoking it twice in the caller will look a little odd too,
I still think that's where the check belongs.
scrub_free_pages is called from idle loop as
else if ( !softirq_pending(cpu) && !scrub_free_pages() )
pm_idle();
so softirq_pending() is unnecessary here.
(Not sure why you are saying it would be invoked twice)
-boris
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