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Index: sys/vm/vm_page.c
===================================================================
--- sys/vm/vm_page.c
+++ sys/vm/vm_page.c
@@ -3097,18 +3097,27 @@
return (&vm_pagequeue_domain(m)->vmd_pagequeues[queue].pq_mutex);
}
-static inline void
-vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m)
+static inline bool
+vm_pqbatch_process_page(struct vm_pagequeue *pq, vm_page_t m, int queue)
{
struct vm_domain *vmd;
uint8_t aflags;
CRITICAL_ASSERT(curthread);
vm_pagequeue_assert_locked(pq);
- KASSERT(pq == vm_page_pagequeue(m),
- ("page %p doesn't belong to %p", m, pq));
- aflags = m->aflags;
+ /*
+ * The page queue lock prevents m->queue from changing after the check
+ * below. There is one exception: the page daemon may change m->queue
+ * from PQ_INACTIVE to PQ_NONE prior to freeing m, with only the page
+ * lock held. However, in this case all of m's queue state flags will
+ * be clear, so this function will have no effect.
+ */
+ aflags = (m->aflags & PGA_QUEUE_STATE_MASK);
+ atomic_thread_fence_acq();
+ if (__predict_false(m->queue != queue))
+ return (false);
+
if ((aflags & PGA_DEQUEUE) != 0) {
if (__predict_true((aflags & PGA_ENQUEUED) != 0)) {
TAILQ_REMOVE(&pq->pq_pl, m, plinks.q);
@@ -3137,21 +3146,17 @@
*/
vm_page_aflag_clear(m, PGA_REQUEUE | PGA_REQUEUE_HEAD);
}
+ return (true);
}
static void
vm_pqbatch_process(struct vm_pagequeue *pq, struct vm_batchqueue *bq,
uint8_t queue)
{
- vm_page_t m;
int i;
- for (i = 0; i < bq->bq_cnt; i++) {
- m = bq->bq_pa[i];
- if (__predict_false(m->queue != queue))
- continue;
- vm_pqbatch_process_page(pq, m);
- }
+ for (i = 0; i < bq->bq_cnt; i++)
+ (void)vm_pqbatch_process_page(pq, bq->bq_pa[i], queue);
vm_batchqueue_init(bq);
}
@@ -3187,9 +3192,7 @@
* page queue lock. In this case, the page lock prevents the page
* from being logically enqueued elsewhere.
*/
- if (__predict_true(m->queue == queue))
- vm_pqbatch_process_page(pq, m);
- else {
+ if (!vm_pqbatch_process_page(pq, m, queue)) {
KASSERT(m->queue == PQ_NONE,
("invalid queue transition for page %p", m));
KASSERT((m->aflags & PGA_ENQUEUED) == 0,
Index: sys/vm/vm_pageout.c
===================================================================
--- sys/vm/vm_pageout.c
+++ sys/vm/vm_pageout.c
@@ -1550,11 +1550,13 @@
* Because we dequeued the page and have already
* checked for concurrent dequeue and enqueue
* requests, we can safely disassociate the page
- * from the inactive queue.
+ * from the inactive queue even without the inactive
+ * page queue lock.
*/
+ m->queue = PQ_NONE;
+ atomic_thread_fence_rel();
KASSERT((m->aflags & PGA_QUEUE_STATE_MASK) == 0,
("page %p has queue state", m));
- m->queue = PQ_NONE;
vm_page_free(m);
page_shortage--;
} else if ((object->flags & OBJ_DEAD) == 0)

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