FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_pageq.c

     /*-
      * Copyright (c) 1998 Matthew Dillon.  All Rights Reserved.
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
      * 2. Redistributions in binary form must reproduce the above copyright
      *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
     * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
     * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
     * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
     * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
     * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/lock.h>
    #include <sys/malloc.h>
    #include <sys/mutex.h>
    #include <sys/proc.h>
    #include <sys/vmmeter.h>
    #include <sys/vnode.h>
    
    #include <vm/vm.h>
    #include <vm/vm_param.h>
    #include <vm/vm_kern.h>
    #include <vm/vm_object.h>
    #include <vm/vm_page.h>
    #include <vm/vm_pageout.h>
    #include <vm/vm_pager.h>
    #include <vm/vm_extern.h>
    
    struct vpgqueues vm_page_queues[PQ_COUNT];
    
    void
    vm_pageq_init(void) 
    {
            int i;
    
            for (i = 0; i < PQ_L2_SIZE; i++) {
                    vm_page_queues[PQ_FREE+i].cnt = &cnt.v_free_count;
            }
            for (i = 0; i < PQ_L2_SIZE; i++) {
                    vm_page_queues[PQ_CACHE+i].cnt = &cnt.v_cache_count;
            }
            vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count;
            vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count;
            vm_page_queues[PQ_HOLD].cnt = &cnt.v_active_count;
    
            for (i = 0; i < PQ_COUNT; i++) {
                    TAILQ_INIT(&vm_page_queues[i].pl);
            }
    }
    
    void
    vm_pageq_requeue(vm_page_t m)
    {
            int queue = m->queue;
            struct vpgqueues *vpq;
    
            if (queue != PQ_NONE) {
                    vpq = &vm_page_queues[queue];
                    TAILQ_REMOVE(&vpq->pl, m, pageq);
                    TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
            }
    }
    
    /*
     *      vm_pageq_enqueue:
     */
    void
    vm_pageq_enqueue(int queue, vm_page_t m)
    {
            struct vpgqueues *vpq;
    
            vpq = &vm_page_queues[queue];
            m->queue = queue;
            TAILQ_INSERT_TAIL(&vpq->pl, m, pageq);
            ++*vpq->cnt;
            ++vpq->lcnt;
    }
    
    /*
    *      vm_add_new_page:
    *
    *      Add a new page to the freelist for use by the system.
    */
   vm_page_t
   vm_pageq_add_new_page(vm_paddr_t pa)
   {
           vm_page_t m;
   
           GIANT_REQUIRED;
   
           ++cnt.v_page_count;
           m = PHYS_TO_VM_PAGE(pa);
           m->phys_addr = pa;
           m->flags = 0;
           m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK;
           pmap_page_init(m);
           vm_pageq_enqueue(m->pc + PQ_FREE, m);
           return (m);
   }
   
   /*
    * vm_pageq_remove_nowakeup:
    *
    *      vm_page_unqueue() without any wakeup
    *
    *      The queue containing the given page must be locked.
    *      This routine may not block.
    */
   void
   vm_pageq_remove_nowakeup(vm_page_t m)
   {
           int queue = m->queue;
           struct vpgqueues *pq;
           if (queue != PQ_NONE) {
                   pq = &vm_page_queues[queue];
                   m->queue = PQ_NONE;
                   TAILQ_REMOVE(&pq->pl, m, pageq);
                   (*pq->cnt)--;
                   pq->lcnt--;
           }
   }
   
   /*
    * vm_pageq_remove:
    *
    *      Remove a page from its queue.
    *
    *      The queue containing the given page must be locked.
    *      This routine may not block.
    */
   void
   vm_pageq_remove(vm_page_t m)
   {
           int queue = m->queue;
           struct vpgqueues *pq;
   
           if (queue != PQ_NONE) {
                   m->queue = PQ_NONE;
                   pq = &vm_page_queues[queue];
                   TAILQ_REMOVE(&pq->pl, m, pageq);
                   (*pq->cnt)--;
                   pq->lcnt--;
                   if ((queue - m->pc) == PQ_CACHE) {
                           if (vm_paging_needed())
                                   pagedaemon_wakeup();
                   }
           }
   }
   
   #if PQ_L2_SIZE > 1
   
   /*
    *      vm_pageq_find:
    *
    *      Find a page on the specified queue with color optimization.
    *
    *      The page coloring optimization attempts to locate a page
    *      that does not overload other nearby pages in the object in
    *      the cpu's L2 cache.  We need this optimization because cpu
    *      caches tend to be physical caches, while object spaces tend 
    *      to be virtual.
    *
    *      The specified queue must be locked.
    *      This routine may not block.
    *
    *      This routine may only be called from the vm_pageq_find()
    *      function in this file.
    */
   static __inline vm_page_t
   _vm_pageq_find(int basequeue, int index)
   {
           int i;
           vm_page_t m = NULL;
           struct vpgqueues *pq;
   
           pq = &vm_page_queues[basequeue];
   
           /*
            * Note that for the first loop, index+i and index-i wind up at the
            * same place.  Even though this is not totally optimal, we've already
            * blown it by missing the cache case so we do not care.
            */
           for (i = PQ_L2_SIZE / 2; i > 0; --i) {
                   if ((m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl)) != NULL)
                           break;
   
                   if ((m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl)) != NULL)
                           break;
           }
           return (m);
   }
   #endif          /* PQ_L2_SIZE > 1 */
   
   vm_page_t
   vm_pageq_find(int basequeue, int index, boolean_t prefer_zero)
   {
           vm_page_t m;
   
   #if PQ_L2_SIZE > 1
           if (prefer_zero) {
                   m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist);
           } else {
                   m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl);
           }
           if (m == NULL) {
                   m = _vm_pageq_find(basequeue, index);
           }
   #else
           if (prefer_zero) {
                   m = TAILQ_LAST(&vm_page_queues[basequeue].pl, pglist);
           } else {
                   m = TAILQ_FIRST(&vm_page_queues[basequeue].pl);
           }
   #endif
           return (m);
   }
   

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