diff options
| -rw-r--r-- | sys/vm/vm_pageout.c | 56 |
1 files changed, 35 insertions, 21 deletions
diff --git a/sys/vm/vm_pageout.c b/sys/vm/vm_pageout.c index 6ac0acb..3994ce1 100644 --- a/sys/vm/vm_pageout.c +++ b/sys/vm/vm_pageout.c @@ -889,6 +889,12 @@ vm_pageout_scan(int pass) */ uma_reclaim(); + /* + * The addl_page_shortage is the the number of temporarily + * stuck pages in the inactive queue. In other words, the + * number of pages from cnt.v_inactive_count that should be + * discounted in setting the target for the active queue scan. + */ addl_page_shortage = atomic_readandclear_int(&vm_pageout_deficit); /* @@ -945,38 +951,31 @@ vm_pageout_scan(int pass) ("Unmanaged page %p cannot be in inactive queue", m)); /* - * Lock the page. + * The page or object lock acquisitions fail if the + * page was removed from the queue or moved to a + * different position within the queue. In either + * case, addl_page_shortage should not be incremented. */ if (!vm_pageout_page_lock(m, &next)) { vm_page_unlock(m); - addl_page_shortage++; continue; } - - /* - * A held page may be undergoing I/O, so skip it. - */ - if (m->hold_count) { + object = m->object; + if (!VM_OBJECT_TRYLOCK(object) && + !vm_pageout_fallback_object_lock(m, &next)) { vm_page_unlock(m); - vm_page_requeue(m); - addl_page_shortage++; + VM_OBJECT_UNLOCK(object); continue; } /* - * Don't mess with busy pages, keep in the front of the - * queue, most likely are being paged out. + * Don't mess with busy pages, keep them at at the + * front of the queue, most likely they are being + * paged out. Increment addl_page_shortage for busy + * pages, because they may leave the inactive queue + * shortly after page scan is finished. */ - object = m->object; - if (!VM_OBJECT_TRYLOCK(object) && - (!vm_pageout_fallback_object_lock(m, &next) || - m->hold_count != 0)) { - VM_OBJECT_UNLOCK(object); - vm_page_unlock(m); - addl_page_shortage++; - continue; - } - if (m->busy || (m->oflags & VPO_BUSY)) { + if (m->busy != 0 || (m->oflags & VPO_BUSY) != 0) { vm_page_unlock(m); VM_OBJECT_UNLOCK(object); addl_page_shortage++; @@ -1036,6 +1035,21 @@ vm_pageout_scan(int pass) goto relock_queues; } + if (m->hold_count != 0) { + vm_page_unlock(m); + VM_OBJECT_UNLOCK(object); + + /* + * Held pages are essentially stuck in the + * queue. So, they ought to be discounted + * from cnt.v_inactive_count. See the + * calculation of the page_shortage for the + * loop over the active queue below. + */ + addl_page_shortage++; + goto relock_queues; + } + /* * If the upper level VM system does not believe that the page * is fully dirty, but it is mapped for write access, then we |
