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65bae14d77
free pages queue. This is presently needed by contigmalloc1(). - Move a sanity check against attempted double allocation of two pages to the same vm object offset from vm_page_alloc() to vm_page_insert(). This provides better protection because double allocation could occur through a direct call to vm_page_insert(), such as that by vm_page_rename(). - Modify contigmalloc1() to hold the mutex synchronizing access to the free pages queue while it scans vm_page_array in search of free pages. - Correct a potential leak of pages by contigmalloc1() that I introduced in revision 1.20: We must convert all cache queue pages to free pages before we begin removing free pages from the free queue. Otherwise, if we have to restart the scan because we are unable to acquire the vm object lock that is necessary to convert a cache queue page to a free page, we leak those free pages already removed from the free queue.
1792 lines
44 KiB
C
1792 lines
44 KiB
C
/*
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* Copyright (c) 1991 Regents of the University of California.
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* All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91
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*/
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/*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Authors: Avadis Tevanian, Jr., Michael Wayne Young
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*/
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/*
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* GENERAL RULES ON VM_PAGE MANIPULATION
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*
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* - a pageq mutex is required when adding or removing a page from a
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* page queue (vm_page_queue[]), regardless of other mutexes or the
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* busy state of a page.
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*
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* - a hash chain mutex is required when associating or disassociating
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* a page from the VM PAGE CACHE hash table (vm_page_buckets),
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* regardless of other mutexes or the busy state of a page.
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*
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* - either a hash chain mutex OR a busied page is required in order
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* to modify the page flags. A hash chain mutex must be obtained in
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* order to busy a page. A page's flags cannot be modified by a
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* hash chain mutex if the page is marked busy.
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*
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* - The object memq mutex is held when inserting or removing
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* pages from an object (vm_page_insert() or vm_page_remove()). This
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* is different from the object's main mutex.
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*
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* Generally speaking, you have to be aware of side effects when running
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* vm_page ops. A vm_page_lookup() will return with the hash chain
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* locked, whether it was able to lookup the page or not. vm_page_free(),
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* vm_page_cache(), vm_page_activate(), and a number of other routines
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* will release the hash chain mutex for you. Intermediate manipulation
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* routines such as vm_page_flag_set() expect the hash chain to be held
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* on entry and the hash chain will remain held on return.
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*
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* pageq scanning can only occur with the pageq in question locked.
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* We have a known bottleneck with the active queue, but the cache
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* and free queues are actually arrays already.
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*/
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/*
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* Resident memory management module.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/lock.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/proc.h>
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#include <sys/vmmeter.h>
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#include <sys/vnode.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_kern.h>
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#include <vm/vm_object.h>
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#include <vm/vm_page.h>
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#include <vm/vm_pageout.h>
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#include <vm/vm_pager.h>
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#include <vm/vm_extern.h>
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#include <vm/uma.h>
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#include <vm/uma_int.h>
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/*
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* Associated with page of user-allocatable memory is a
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* page structure.
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*/
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struct mtx vm_page_queue_mtx;
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struct mtx vm_page_queue_free_mtx;
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vm_page_t vm_page_array = 0;
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int vm_page_array_size = 0;
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long first_page = 0;
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int vm_page_zero_count = 0;
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/*
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* vm_set_page_size:
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*
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* Sets the page size, perhaps based upon the memory
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* size. Must be called before any use of page-size
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* dependent functions.
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*/
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void
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vm_set_page_size(void)
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{
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if (cnt.v_page_size == 0)
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cnt.v_page_size = PAGE_SIZE;
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if (((cnt.v_page_size - 1) & cnt.v_page_size) != 0)
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panic("vm_set_page_size: page size not a power of two");
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}
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/*
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* vm_page_startup:
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*
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* Initializes the resident memory module.
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*
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* Allocates memory for the page cells, and
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* for the object/offset-to-page hash table headers.
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* Each page cell is initialized and placed on the free list.
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*/
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vm_offset_t
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vm_page_startup(vm_offset_t starta, vm_offset_t enda, vm_offset_t vaddr)
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{
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vm_offset_t mapped;
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vm_size_t npages;
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vm_paddr_t page_range;
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vm_paddr_t new_end;
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int i;
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vm_paddr_t pa;
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int nblocks;
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vm_paddr_t last_pa;
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/* the biggest memory array is the second group of pages */
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vm_paddr_t end;
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vm_paddr_t biggestsize;
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int biggestone;
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vm_paddr_t total;
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vm_size_t bootpages;
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total = 0;
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biggestsize = 0;
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biggestone = 0;
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nblocks = 0;
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vaddr = round_page(vaddr);
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for (i = 0; phys_avail[i + 1]; i += 2) {
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phys_avail[i] = round_page(phys_avail[i]);
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phys_avail[i + 1] = trunc_page(phys_avail[i + 1]);
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}
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for (i = 0; phys_avail[i + 1]; i += 2) {
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vm_paddr_t size = phys_avail[i + 1] - phys_avail[i];
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if (size > biggestsize) {
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biggestone = i;
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biggestsize = size;
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}
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++nblocks;
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total += size;
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}
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end = phys_avail[biggestone+1];
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/*
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* Initialize the locks. Recursive acquisition of the vm page
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* queue free mutex begins in contigmalloc1().
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*/
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mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF);
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mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL,
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MTX_RECURSE | MTX_SPIN);
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/*
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* Initialize the queue headers for the free queue, the active queue
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* and the inactive queue.
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*/
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vm_pageq_init();
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/*
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* Allocate memory for use when boot strapping the kernel memory
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* allocator.
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*/
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bootpages = UMA_BOOT_PAGES * UMA_SLAB_SIZE;
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new_end = end - bootpages;
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new_end = trunc_page(new_end);
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mapped = pmap_map(&vaddr, new_end, end,
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VM_PROT_READ | VM_PROT_WRITE);
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bzero((caddr_t) mapped, end - new_end);
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uma_startup((caddr_t)mapped);
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/*
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* Compute the number of pages of memory that will be available for
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* use (taking into account the overhead of a page structure per
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* page).
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*/
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first_page = phys_avail[0] / PAGE_SIZE;
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page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page;
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npages = (total - (page_range * sizeof(struct vm_page)) -
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(end - new_end)) / PAGE_SIZE;
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end = new_end;
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/*
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* Reserve an unmapped guard page to trap access to vm_page_array[-1].
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*/
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vaddr += PAGE_SIZE;
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/*
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* Initialize the mem entry structures now, and put them in the free
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* queue.
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*/
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new_end = trunc_page(end - page_range * sizeof(struct vm_page));
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mapped = pmap_map(&vaddr, new_end, end,
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VM_PROT_READ | VM_PROT_WRITE);
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vm_page_array = (vm_page_t) mapped;
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phys_avail[biggestone + 1] = new_end;
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/*
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* Clear all of the page structures
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*/
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bzero((caddr_t) vm_page_array, page_range * sizeof(struct vm_page));
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vm_page_array_size = page_range;
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/*
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* Construct the free queue(s) in descending order (by physical
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* address) so that the first 16MB of physical memory is allocated
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* last rather than first. On large-memory machines, this avoids
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* the exhaustion of low physical memory before isa_dmainit has run.
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*/
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cnt.v_page_count = 0;
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cnt.v_free_count = 0;
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for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) {
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pa = phys_avail[i];
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last_pa = phys_avail[i + 1];
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while (pa < last_pa && npages-- > 0) {
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vm_pageq_add_new_page(pa);
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pa += PAGE_SIZE;
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}
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}
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return (vaddr);
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}
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void
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vm_page_flag_set(vm_page_t m, unsigned short bits)
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{
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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m->flags |= bits;
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}
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void
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vm_page_flag_clear(vm_page_t m, unsigned short bits)
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{
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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m->flags &= ~bits;
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}
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void
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vm_page_busy(vm_page_t m)
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{
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KASSERT((m->flags & PG_BUSY) == 0,
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("vm_page_busy: page already busy!!!"));
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vm_page_flag_set(m, PG_BUSY);
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}
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/*
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* vm_page_flash:
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*
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* wakeup anyone waiting for the page.
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*/
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void
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vm_page_flash(vm_page_t m)
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{
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if (m->flags & PG_WANTED) {
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vm_page_flag_clear(m, PG_WANTED);
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wakeup(m);
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}
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}
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/*
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* vm_page_wakeup:
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*
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* clear the PG_BUSY flag and wakeup anyone waiting for the
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* page.
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*
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*/
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void
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vm_page_wakeup(vm_page_t m)
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{
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KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!"));
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vm_page_flag_clear(m, PG_BUSY);
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vm_page_flash(m);
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}
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void
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vm_page_io_start(vm_page_t m)
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{
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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m->busy++;
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}
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void
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vm_page_io_finish(vm_page_t m)
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{
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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m->busy--;
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if (m->busy == 0)
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vm_page_flash(m);
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}
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/*
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* Keep page from being freed by the page daemon
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* much of the same effect as wiring, except much lower
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* overhead and should be used only for *very* temporary
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* holding ("wiring").
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*/
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void
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vm_page_hold(vm_page_t mem)
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{
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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mem->hold_count++;
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}
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void
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vm_page_unhold(vm_page_t mem)
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{
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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--mem->hold_count;
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KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!"));
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if (mem->hold_count == 0 && mem->queue == PQ_HOLD)
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vm_page_free_toq(mem);
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}
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/*
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* vm_page_free:
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*
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* Free a page
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*
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* The clearing of PG_ZERO is a temporary safety until the code can be
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* reviewed to determine that PG_ZERO is being properly cleared on
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* write faults or maps. PG_ZERO was previously cleared in
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* vm_page_alloc().
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*/
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void
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vm_page_free(vm_page_t m)
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{
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vm_page_flag_clear(m, PG_ZERO);
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vm_page_free_toq(m);
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vm_page_zero_idle_wakeup();
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}
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/*
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* vm_page_free_zero:
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*
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* Free a page to the zerod-pages queue
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*/
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void
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vm_page_free_zero(vm_page_t m)
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{
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vm_page_flag_set(m, PG_ZERO);
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vm_page_free_toq(m);
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}
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/*
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* vm_page_sleep_if_busy:
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*
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* Sleep and release the page queues lock if PG_BUSY is set or,
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* if also_m_busy is TRUE, busy is non-zero. Returns TRUE if the
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* thread slept and the page queues lock was released.
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* Otherwise, retains the page queues lock and returns FALSE.
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*/
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int
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vm_page_sleep_if_busy(vm_page_t m, int also_m_busy, const char *msg)
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{
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int is_object_locked;
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mtx_assert(&vm_page_queue_mtx, MA_OWNED);
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if ((m->flags & PG_BUSY) || (also_m_busy && m->busy)) {
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vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
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/*
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* Remove mtx_owned() after vm_object locking is finished.
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*/
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if ((is_object_locked = m->object != NULL &&
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mtx_owned(&m->object->mtx)))
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mtx_unlock(&m->object->mtx);
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msleep(m, &vm_page_queue_mtx, PDROP | PVM, msg, 0);
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if (is_object_locked)
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mtx_lock(&m->object->mtx);
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return (TRUE);
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}
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return (FALSE);
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}
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|
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/*
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* vm_page_dirty:
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*
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* make page all dirty
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*/
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void
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vm_page_dirty(vm_page_t m)
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{
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KASSERT(m->queue - m->pc != PQ_CACHE,
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("vm_page_dirty: page in cache!"));
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KASSERT(m->queue - m->pc != PQ_FREE,
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("vm_page_dirty: page is free!"));
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m->dirty = VM_PAGE_BITS_ALL;
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}
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|
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/*
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* vm_page_splay:
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*
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|
* Implements Sleator and Tarjan's top-down splay algorithm. Returns
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* the vm_page containing the given pindex. If, however, that
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* pindex is not found in the vm_object, returns a vm_page that is
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* adjacent to the pindex, coming before or after it.
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|
*/
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vm_page_t
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vm_page_splay(vm_pindex_t pindex, vm_page_t root)
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|
{
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struct vm_page dummy;
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|
vm_page_t lefttreemax, righttreemin, y;
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|
if (root == NULL)
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return (root);
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lefttreemax = righttreemin = &dummy;
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for (;; root = y) {
|
|
if (pindex < root->pindex) {
|
|
if ((y = root->left) == NULL)
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|
break;
|
|
if (pindex < y->pindex) {
|
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/* Rotate right. */
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|
root->left = y->right;
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y->right = root;
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root = y;
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if ((y = root->left) == NULL)
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break;
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}
|
|
/* Link into the new root's right tree. */
|
|
righttreemin->left = root;
|
|
righttreemin = root;
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|
} else if (pindex > root->pindex) {
|
|
if ((y = root->right) == NULL)
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break;
|
|
if (pindex > y->pindex) {
|
|
/* Rotate left. */
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|
root->right = y->left;
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|
y->left = root;
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root = y;
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if ((y = root->right) == NULL)
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break;
|
|
}
|
|
/* Link into the new root's left tree. */
|
|
lefttreemax->right = root;
|
|
lefttreemax = root;
|
|
} else
|
|
break;
|
|
}
|
|
/* Assemble the new root. */
|
|
lefttreemax->right = root->left;
|
|
righttreemin->left = root->right;
|
|
root->left = dummy.right;
|
|
root->right = dummy.left;
|
|
return (root);
|
|
}
|
|
|
|
/*
|
|
* vm_page_insert: [ internal use only ]
|
|
*
|
|
* Inserts the given mem entry into the object and object list.
|
|
*
|
|
* The pagetables are not updated but will presumably fault the page
|
|
* in if necessary, or if a kernel page the caller will at some point
|
|
* enter the page into the kernel's pmap. We are not allowed to block
|
|
* here so we *can't* do this anyway.
|
|
*
|
|
* The object and page must be locked, and must be splhigh.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex)
|
|
{
|
|
vm_page_t root;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
if (m->object != NULL)
|
|
panic("vm_page_insert: page already inserted");
|
|
|
|
/*
|
|
* Record the object/offset pair in this page
|
|
*/
|
|
m->object = object;
|
|
m->pindex = pindex;
|
|
|
|
/*
|
|
* Now link into the object's ordered list of backed pages.
|
|
*/
|
|
root = object->root;
|
|
if (root == NULL) {
|
|
m->left = NULL;
|
|
m->right = NULL;
|
|
TAILQ_INSERT_TAIL(&object->memq, m, listq);
|
|
} else {
|
|
root = vm_page_splay(pindex, root);
|
|
if (pindex < root->pindex) {
|
|
m->left = root->left;
|
|
m->right = root;
|
|
root->left = NULL;
|
|
TAILQ_INSERT_BEFORE(root, m, listq);
|
|
} else if (pindex == root->pindex)
|
|
panic("vm_page_insert: offset already allocated");
|
|
else {
|
|
m->right = root->right;
|
|
m->left = root;
|
|
root->right = NULL;
|
|
TAILQ_INSERT_AFTER(&object->memq, root, m, listq);
|
|
}
|
|
}
|
|
object->root = m;
|
|
object->generation++;
|
|
|
|
/*
|
|
* show that the object has one more resident page.
|
|
*/
|
|
object->resident_page_count++;
|
|
|
|
/*
|
|
* Since we are inserting a new and possibly dirty page,
|
|
* update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags.
|
|
*/
|
|
if (m->flags & PG_WRITEABLE)
|
|
vm_object_set_writeable_dirty(object);
|
|
}
|
|
|
|
/*
|
|
* vm_page_remove:
|
|
* NOTE: used by device pager as well -wfj
|
|
*
|
|
* Removes the given mem entry from the object/offset-page
|
|
* table and the object page list, but do not invalidate/terminate
|
|
* the backing store.
|
|
*
|
|
* The object and page must be locked, and at splhigh.
|
|
* The underlying pmap entry (if any) is NOT removed here.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_remove(vm_page_t m)
|
|
{
|
|
vm_object_t object;
|
|
vm_page_t root;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->object == NULL)
|
|
return;
|
|
#ifndef __alpha__
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
#endif
|
|
if ((m->flags & PG_BUSY) == 0) {
|
|
panic("vm_page_remove: page not busy");
|
|
}
|
|
|
|
/*
|
|
* Basically destroy the page.
|
|
*/
|
|
vm_page_wakeup(m);
|
|
|
|
object = m->object;
|
|
|
|
/*
|
|
* Now remove from the object's list of backed pages.
|
|
*/
|
|
if (m != object->root)
|
|
vm_page_splay(m->pindex, object->root);
|
|
if (m->left == NULL)
|
|
root = m->right;
|
|
else {
|
|
root = vm_page_splay(m->pindex, m->left);
|
|
root->right = m->right;
|
|
}
|
|
object->root = root;
|
|
TAILQ_REMOVE(&object->memq, m, listq);
|
|
|
|
/*
|
|
* And show that the object has one fewer resident page.
|
|
*/
|
|
object->resident_page_count--;
|
|
object->generation++;
|
|
|
|
m->object = NULL;
|
|
}
|
|
|
|
/*
|
|
* vm_page_lookup:
|
|
*
|
|
* Returns the page associated with the object/offset
|
|
* pair specified; if none is found, NULL is returned.
|
|
*
|
|
* The object must be locked.
|
|
* This routine may not block.
|
|
* This is a critical path routine
|
|
*/
|
|
vm_page_t
|
|
vm_page_lookup(vm_object_t object, vm_pindex_t pindex)
|
|
{
|
|
vm_page_t m;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
if ((m = object->root) != NULL && m->pindex != pindex) {
|
|
m = vm_page_splay(pindex, m);
|
|
if ((object->root = m)->pindex != pindex)
|
|
m = NULL;
|
|
}
|
|
return (m);
|
|
}
|
|
|
|
/*
|
|
* vm_page_rename:
|
|
*
|
|
* Move the given memory entry from its
|
|
* current object to the specified target object/offset.
|
|
*
|
|
* The object must be locked.
|
|
* This routine may not block.
|
|
*
|
|
* Note: this routine will raise itself to splvm(), the caller need not.
|
|
*
|
|
* Note: swap associated with the page must be invalidated by the move. We
|
|
* have to do this for several reasons: (1) we aren't freeing the
|
|
* page, (2) we are dirtying the page, (3) the VM system is probably
|
|
* moving the page from object A to B, and will then later move
|
|
* the backing store from A to B and we can't have a conflict.
|
|
*
|
|
* Note: we *always* dirty the page. It is necessary both for the
|
|
* fact that we moved it, and because we may be invalidating
|
|
* swap. If the page is on the cache, we have to deactivate it
|
|
* or vm_page_dirty() will panic. Dirty pages are not allowed
|
|
* on the cache.
|
|
*/
|
|
void
|
|
vm_page_rename(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
vm_page_remove(m);
|
|
vm_page_insert(m, new_object, new_pindex);
|
|
if (m->queue - m->pc == PQ_CACHE)
|
|
vm_page_deactivate(m);
|
|
vm_page_dirty(m);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_select_cache:
|
|
*
|
|
* Find a page on the cache queue with color optimization. As pages
|
|
* might be found, but not applicable, they are deactivated. This
|
|
* keeps us from using potentially busy cached pages.
|
|
*
|
|
* This routine must be called at splvm().
|
|
* This routine may not block.
|
|
*/
|
|
vm_page_t
|
|
vm_page_select_cache(int color)
|
|
{
|
|
vm_page_t m;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
while (TRUE) {
|
|
m = vm_pageq_find(PQ_CACHE, color, FALSE);
|
|
if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
|
|
m->hold_count || m->wire_count ||
|
|
(!VM_OBJECT_TRYLOCK(m->object) &&
|
|
!VM_OBJECT_LOCKED(m->object)))) {
|
|
vm_page_deactivate(m);
|
|
continue;
|
|
}
|
|
return m;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_page_alloc:
|
|
*
|
|
* Allocate and return a memory cell associated
|
|
* with this VM object/offset pair.
|
|
*
|
|
* page_req classes:
|
|
* VM_ALLOC_NORMAL normal process request
|
|
* VM_ALLOC_SYSTEM system *really* needs a page
|
|
* VM_ALLOC_INTERRUPT interrupt time request
|
|
* VM_ALLOC_ZERO zero page
|
|
*
|
|
* This routine may not block.
|
|
*
|
|
* Additional special handling is required when called from an
|
|
* interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with
|
|
* the page cache in this case.
|
|
*/
|
|
vm_page_t
|
|
vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
|
|
{
|
|
vm_object_t m_object;
|
|
vm_page_t m = NULL;
|
|
int color, flags, page_req, s;
|
|
|
|
page_req = req & VM_ALLOC_CLASS_MASK;
|
|
|
|
if ((req & VM_ALLOC_NOOBJ) == 0) {
|
|
KASSERT(object != NULL,
|
|
("vm_page_alloc: NULL object."));
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
color = (pindex + object->pg_color) & PQ_L2_MASK;
|
|
} else
|
|
color = pindex & PQ_L2_MASK;
|
|
|
|
/*
|
|
* The pager is allowed to eat deeper into the free page list.
|
|
*/
|
|
if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) {
|
|
page_req = VM_ALLOC_SYSTEM;
|
|
};
|
|
|
|
s = splvm();
|
|
loop:
|
|
mtx_lock_spin(&vm_page_queue_free_mtx);
|
|
if (cnt.v_free_count > cnt.v_free_reserved ||
|
|
(page_req == VM_ALLOC_SYSTEM &&
|
|
cnt.v_cache_count == 0 &&
|
|
cnt.v_free_count > cnt.v_interrupt_free_min) ||
|
|
(page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0)) {
|
|
/*
|
|
* Allocate from the free queue if the number of free pages
|
|
* exceeds the minimum for the request class.
|
|
*/
|
|
m = vm_pageq_find(PQ_FREE, color, (req & VM_ALLOC_ZERO) != 0);
|
|
} else if (page_req != VM_ALLOC_INTERRUPT) {
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
/*
|
|
* Allocatable from cache (non-interrupt only). On success,
|
|
* we must free the page and try again, thus ensuring that
|
|
* cnt.v_*_free_min counters are replenished.
|
|
*/
|
|
vm_page_lock_queues();
|
|
if ((m = vm_page_select_cache(color)) == NULL) {
|
|
vm_page_unlock_queues();
|
|
splx(s);
|
|
#if defined(DIAGNOSTIC)
|
|
if (cnt.v_cache_count > 0)
|
|
printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count);
|
|
#endif
|
|
atomic_add_int(&vm_pageout_deficit, 1);
|
|
pagedaemon_wakeup();
|
|
return (NULL);
|
|
}
|
|
KASSERT(m->dirty == 0, ("Found dirty cache page %p", m));
|
|
m_object = m->object;
|
|
VM_OBJECT_LOCK_ASSERT(m_object, MA_OWNED);
|
|
vm_page_busy(m);
|
|
pmap_remove_all(m);
|
|
vm_page_free(m);
|
|
vm_page_unlock_queues();
|
|
if (m_object != object)
|
|
VM_OBJECT_UNLOCK(m_object);
|
|
goto loop;
|
|
} else {
|
|
/*
|
|
* Not allocatable from cache from interrupt, give up.
|
|
*/
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
splx(s);
|
|
atomic_add_int(&vm_pageout_deficit, 1);
|
|
pagedaemon_wakeup();
|
|
return (NULL);
|
|
}
|
|
|
|
/*
|
|
* At this point we had better have found a good page.
|
|
*/
|
|
|
|
KASSERT(
|
|
m != NULL,
|
|
("vm_page_alloc(): missing page on free queue\n")
|
|
);
|
|
|
|
/*
|
|
* Remove from free queue
|
|
*/
|
|
|
|
vm_pageq_remove_nowakeup(m);
|
|
|
|
/*
|
|
* Initialize structure. Only the PG_ZERO flag is inherited.
|
|
*/
|
|
flags = PG_BUSY;
|
|
if (m->flags & PG_ZERO) {
|
|
vm_page_zero_count--;
|
|
if (req & VM_ALLOC_ZERO)
|
|
flags = PG_ZERO | PG_BUSY;
|
|
}
|
|
m->flags = flags;
|
|
if (req & VM_ALLOC_WIRED) {
|
|
atomic_add_int(&cnt.v_wire_count, 1);
|
|
m->wire_count = 1;
|
|
} else
|
|
m->wire_count = 0;
|
|
m->hold_count = 0;
|
|
m->act_count = 0;
|
|
m->busy = 0;
|
|
m->valid = 0;
|
|
KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m));
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
|
|
/*
|
|
* vm_page_insert() is safe prior to the splx(). Note also that
|
|
* inserting a page here does not insert it into the pmap (which
|
|
* could cause us to block allocating memory). We cannot block
|
|
* anywhere.
|
|
*/
|
|
if ((req & VM_ALLOC_NOOBJ) == 0)
|
|
vm_page_insert(m, object, pindex);
|
|
else
|
|
m->pindex = pindex;
|
|
|
|
/*
|
|
* Don't wakeup too often - wakeup the pageout daemon when
|
|
* we would be nearly out of memory.
|
|
*/
|
|
if (vm_paging_needed())
|
|
pagedaemon_wakeup();
|
|
|
|
splx(s);
|
|
return (m);
|
|
}
|
|
|
|
/*
|
|
* vm_wait: (also see VM_WAIT macro)
|
|
*
|
|
* Block until free pages are available for allocation
|
|
* - Called in various places before memory allocations.
|
|
*/
|
|
void
|
|
vm_wait(void)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
vm_page_lock_queues();
|
|
if (curproc == pageproc) {
|
|
vm_pageout_pages_needed = 1;
|
|
msleep(&vm_pageout_pages_needed, &vm_page_queue_mtx,
|
|
PDROP | PSWP, "VMWait", 0);
|
|
} else {
|
|
if (!vm_pages_needed) {
|
|
vm_pages_needed = 1;
|
|
wakeup(&vm_pages_needed);
|
|
}
|
|
msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PVM,
|
|
"vmwait", 0);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_waitpfault: (also see VM_WAITPFAULT macro)
|
|
*
|
|
* Block until free pages are available for allocation
|
|
* - Called only in vm_fault so that processes page faulting
|
|
* can be easily tracked.
|
|
* - Sleeps at a lower priority than vm_wait() so that vm_wait()ing
|
|
* processes will be able to grab memory first. Do not change
|
|
* this balance without careful testing first.
|
|
*/
|
|
void
|
|
vm_waitpfault(void)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
vm_page_lock_queues();
|
|
if (!vm_pages_needed) {
|
|
vm_pages_needed = 1;
|
|
wakeup(&vm_pages_needed);
|
|
}
|
|
msleep(&cnt.v_free_count, &vm_page_queue_mtx, PDROP | PUSER,
|
|
"pfault", 0);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_activate:
|
|
*
|
|
* Put the specified page on the active list (if appropriate).
|
|
* Ensure that act_count is at least ACT_INIT but do not otherwise
|
|
* mess with it.
|
|
*
|
|
* The page queues must be locked.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_activate(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
s = splvm();
|
|
if (m->queue != PQ_ACTIVE) {
|
|
if ((m->queue - m->pc) == PQ_CACHE)
|
|
cnt.v_reactivated++;
|
|
vm_pageq_remove(m);
|
|
if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
|
|
if (m->act_count < ACT_INIT)
|
|
m->act_count = ACT_INIT;
|
|
vm_pageq_enqueue(PQ_ACTIVE, m);
|
|
}
|
|
} else {
|
|
if (m->act_count < ACT_INIT)
|
|
m->act_count = ACT_INIT;
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_free_wakeup:
|
|
*
|
|
* Helper routine for vm_page_free_toq() and vm_page_cache(). This
|
|
* routine is called when a page has been added to the cache or free
|
|
* queues.
|
|
*
|
|
* This routine may not block.
|
|
* This routine must be called at splvm()
|
|
*/
|
|
static __inline void
|
|
vm_page_free_wakeup(void)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
/*
|
|
* if pageout daemon needs pages, then tell it that there are
|
|
* some free.
|
|
*/
|
|
if (vm_pageout_pages_needed &&
|
|
cnt.v_cache_count + cnt.v_free_count >= cnt.v_pageout_free_min) {
|
|
wakeup(&vm_pageout_pages_needed);
|
|
vm_pageout_pages_needed = 0;
|
|
}
|
|
/*
|
|
* wakeup processes that are waiting on memory if we hit a
|
|
* high water mark. And wakeup scheduler process if we have
|
|
* lots of memory. this process will swapin processes.
|
|
*/
|
|
if (vm_pages_needed && !vm_page_count_min()) {
|
|
vm_pages_needed = 0;
|
|
wakeup(&cnt.v_free_count);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* vm_page_free_toq:
|
|
*
|
|
* Returns the given page to the PQ_FREE list,
|
|
* disassociating it with any VM object.
|
|
*
|
|
* Object and page must be locked prior to entry.
|
|
* This routine may not block.
|
|
*/
|
|
|
|
void
|
|
vm_page_free_toq(vm_page_t m)
|
|
{
|
|
int s;
|
|
struct vpgqueues *pq;
|
|
vm_object_t object = m->object;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
s = splvm();
|
|
cnt.v_tfree++;
|
|
|
|
if (m->busy || ((m->queue - m->pc) == PQ_FREE)) {
|
|
printf(
|
|
"vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n",
|
|
(u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0,
|
|
m->hold_count);
|
|
if ((m->queue - m->pc) == PQ_FREE)
|
|
panic("vm_page_free: freeing free page");
|
|
else
|
|
panic("vm_page_free: freeing busy page");
|
|
}
|
|
|
|
/*
|
|
* unqueue, then remove page. Note that we cannot destroy
|
|
* the page here because we do not want to call the pager's
|
|
* callback routine until after we've put the page on the
|
|
* appropriate free queue.
|
|
*/
|
|
vm_pageq_remove_nowakeup(m);
|
|
vm_page_remove(m);
|
|
|
|
/*
|
|
* If fictitious remove object association and
|
|
* return, otherwise delay object association removal.
|
|
*/
|
|
if ((m->flags & PG_FICTITIOUS) != 0) {
|
|
splx(s);
|
|
return;
|
|
}
|
|
|
|
m->valid = 0;
|
|
vm_page_undirty(m);
|
|
|
|
if (m->wire_count != 0) {
|
|
if (m->wire_count > 1) {
|
|
panic("vm_page_free: invalid wire count (%d), pindex: 0x%lx",
|
|
m->wire_count, (long)m->pindex);
|
|
}
|
|
panic("vm_page_free: freeing wired page\n");
|
|
}
|
|
|
|
/*
|
|
* If we've exhausted the object's resident pages we want to free
|
|
* it up.
|
|
*/
|
|
if (object &&
|
|
(object->type == OBJT_VNODE) &&
|
|
((object->flags & OBJ_DEAD) == 0)
|
|
) {
|
|
struct vnode *vp = (struct vnode *)object->handle;
|
|
|
|
if (vp) {
|
|
VI_LOCK(vp);
|
|
if (VSHOULDFREE(vp))
|
|
vfree(vp);
|
|
VI_UNLOCK(vp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Clear the UNMANAGED flag when freeing an unmanaged page.
|
|
*/
|
|
if (m->flags & PG_UNMANAGED) {
|
|
m->flags &= ~PG_UNMANAGED;
|
|
}
|
|
|
|
if (m->hold_count != 0) {
|
|
m->flags &= ~PG_ZERO;
|
|
m->queue = PQ_HOLD;
|
|
} else
|
|
m->queue = PQ_FREE + m->pc;
|
|
pq = &vm_page_queues[m->queue];
|
|
mtx_lock_spin(&vm_page_queue_free_mtx);
|
|
pq->lcnt++;
|
|
++(*pq->cnt);
|
|
|
|
/*
|
|
* Put zero'd pages on the end ( where we look for zero'd pages
|
|
* first ) and non-zerod pages at the head.
|
|
*/
|
|
if (m->flags & PG_ZERO) {
|
|
TAILQ_INSERT_TAIL(&pq->pl, m, pageq);
|
|
++vm_page_zero_count;
|
|
} else {
|
|
TAILQ_INSERT_HEAD(&pq->pl, m, pageq);
|
|
}
|
|
mtx_unlock_spin(&vm_page_queue_free_mtx);
|
|
vm_page_free_wakeup();
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_unmanage:
|
|
*
|
|
* Prevent PV management from being done on the page. The page is
|
|
* removed from the paging queues as if it were wired, and as a
|
|
* consequence of no longer being managed the pageout daemon will not
|
|
* touch it (since there is no way to locate the pte mappings for the
|
|
* page). madvise() calls that mess with the pmap will also no longer
|
|
* operate on the page.
|
|
*
|
|
* Beyond that the page is still reasonably 'normal'. Freeing the page
|
|
* will clear the flag.
|
|
*
|
|
* This routine is used by OBJT_PHYS objects - objects using unswappable
|
|
* physical memory as backing store rather then swap-backed memory and
|
|
* will eventually be extended to support 4MB unmanaged physical
|
|
* mappings.
|
|
*/
|
|
void
|
|
vm_page_unmanage(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if ((m->flags & PG_UNMANAGED) == 0) {
|
|
if (m->wire_count == 0)
|
|
vm_pageq_remove(m);
|
|
}
|
|
vm_page_flag_set(m, PG_UNMANAGED);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_wire:
|
|
*
|
|
* Mark this page as wired down by yet
|
|
* another map, removing it from paging queues
|
|
* as necessary.
|
|
*
|
|
* The page queues must be locked.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_wire(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
/*
|
|
* Only bump the wire statistics if the page is not already wired,
|
|
* and only unqueue the page if it is on some queue (if it is unmanaged
|
|
* it is already off the queues).
|
|
*/
|
|
s = splvm();
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->wire_count == 0) {
|
|
if ((m->flags & PG_UNMANAGED) == 0)
|
|
vm_pageq_remove(m);
|
|
atomic_add_int(&cnt.v_wire_count, 1);
|
|
}
|
|
m->wire_count++;
|
|
KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m));
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_unwire:
|
|
*
|
|
* Release one wiring of this page, potentially
|
|
* enabling it to be paged again.
|
|
*
|
|
* Many pages placed on the inactive queue should actually go
|
|
* into the cache, but it is difficult to figure out which. What
|
|
* we do instead, if the inactive target is well met, is to put
|
|
* clean pages at the head of the inactive queue instead of the tail.
|
|
* This will cause them to be moved to the cache more quickly and
|
|
* if not actively re-referenced, freed more quickly. If we just
|
|
* stick these pages at the end of the inactive queue, heavy filesystem
|
|
* meta-data accesses can cause an unnecessary paging load on memory bound
|
|
* processes. This optimization causes one-time-use metadata to be
|
|
* reused more quickly.
|
|
*
|
|
* BUT, if we are in a low-memory situation we have no choice but to
|
|
* put clean pages on the cache queue.
|
|
*
|
|
* A number of routines use vm_page_unwire() to guarantee that the page
|
|
* will go into either the inactive or active queues, and will NEVER
|
|
* be placed in the cache - for example, just after dirtying a page.
|
|
* dirty pages in the cache are not allowed.
|
|
*
|
|
* The page queues must be locked.
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_unwire(vm_page_t m, int activate)
|
|
{
|
|
int s;
|
|
|
|
s = splvm();
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->wire_count > 0) {
|
|
m->wire_count--;
|
|
if (m->wire_count == 0) {
|
|
atomic_subtract_int(&cnt.v_wire_count, 1);
|
|
if (m->flags & PG_UNMANAGED) {
|
|
;
|
|
} else if (activate)
|
|
vm_pageq_enqueue(PQ_ACTIVE, m);
|
|
else {
|
|
vm_page_flag_clear(m, PG_WINATCFLS);
|
|
vm_pageq_enqueue(PQ_INACTIVE, m);
|
|
}
|
|
}
|
|
} else {
|
|
panic("vm_page_unwire: invalid wire count: %d\n", m->wire_count);
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
|
|
/*
|
|
* Move the specified page to the inactive queue. If the page has
|
|
* any associated swap, the swap is deallocated.
|
|
*
|
|
* Normally athead is 0 resulting in LRU operation. athead is set
|
|
* to 1 if we want this page to be 'as if it were placed in the cache',
|
|
* except without unmapping it from the process address space.
|
|
*
|
|
* This routine may not block.
|
|
*/
|
|
static __inline void
|
|
_vm_page_deactivate(vm_page_t m, int athead)
|
|
{
|
|
int s;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
/*
|
|
* Ignore if already inactive.
|
|
*/
|
|
if (m->queue == PQ_INACTIVE)
|
|
return;
|
|
|
|
s = splvm();
|
|
if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) {
|
|
if ((m->queue - m->pc) == PQ_CACHE)
|
|
cnt.v_reactivated++;
|
|
vm_page_flag_clear(m, PG_WINATCFLS);
|
|
vm_pageq_remove(m);
|
|
if (athead)
|
|
TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
|
|
else
|
|
TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq);
|
|
m->queue = PQ_INACTIVE;
|
|
vm_page_queues[PQ_INACTIVE].lcnt++;
|
|
cnt.v_inactive_count++;
|
|
}
|
|
splx(s);
|
|
}
|
|
|
|
void
|
|
vm_page_deactivate(vm_page_t m)
|
|
{
|
|
_vm_page_deactivate(m, 0);
|
|
}
|
|
|
|
/*
|
|
* vm_page_try_to_cache:
|
|
*
|
|
* Returns 0 on failure, 1 on success
|
|
*/
|
|
int
|
|
vm_page_try_to_cache(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->dirty || m->hold_count || m->busy || m->wire_count ||
|
|
(m->flags & (PG_BUSY|PG_UNMANAGED))) {
|
|
return (0);
|
|
}
|
|
vm_page_test_dirty(m);
|
|
if (m->dirty)
|
|
return (0);
|
|
vm_page_cache(m);
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* vm_page_try_to_free()
|
|
*
|
|
* Attempt to free the page. If we cannot free it, we do nothing.
|
|
* 1 is returned on success, 0 on failure.
|
|
*/
|
|
int
|
|
vm_page_try_to_free(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->object != NULL)
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
if (m->dirty || m->hold_count || m->busy || m->wire_count ||
|
|
(m->flags & (PG_BUSY|PG_UNMANAGED))) {
|
|
return (0);
|
|
}
|
|
vm_page_test_dirty(m);
|
|
if (m->dirty)
|
|
return (0);
|
|
vm_page_busy(m);
|
|
pmap_remove_all(m);
|
|
vm_page_free(m);
|
|
return (1);
|
|
}
|
|
|
|
/*
|
|
* vm_page_cache
|
|
*
|
|
* Put the specified page onto the page cache queue (if appropriate).
|
|
*
|
|
* This routine may not block.
|
|
*/
|
|
void
|
|
vm_page_cache(vm_page_t m)
|
|
{
|
|
int s;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy ||
|
|
m->hold_count || m->wire_count) {
|
|
printf("vm_page_cache: attempting to cache busy page\n");
|
|
return;
|
|
}
|
|
if ((m->queue - m->pc) == PQ_CACHE)
|
|
return;
|
|
|
|
/*
|
|
* Remove all pmaps and indicate that the page is not
|
|
* writeable or mapped.
|
|
*/
|
|
pmap_remove_all(m);
|
|
if (m->dirty != 0) {
|
|
panic("vm_page_cache: caching a dirty page, pindex: %ld",
|
|
(long)m->pindex);
|
|
}
|
|
s = splvm();
|
|
vm_pageq_remove_nowakeup(m);
|
|
vm_pageq_enqueue(PQ_CACHE + m->pc, m);
|
|
vm_page_free_wakeup();
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* vm_page_dontneed
|
|
*
|
|
* Cache, deactivate, or do nothing as appropriate. This routine
|
|
* is typically used by madvise() MADV_DONTNEED.
|
|
*
|
|
* Generally speaking we want to move the page into the cache so
|
|
* it gets reused quickly. However, this can result in a silly syndrome
|
|
* due to the page recycling too quickly. Small objects will not be
|
|
* fully cached. On the otherhand, if we move the page to the inactive
|
|
* queue we wind up with a problem whereby very large objects
|
|
* unnecessarily blow away our inactive and cache queues.
|
|
*
|
|
* The solution is to move the pages based on a fixed weighting. We
|
|
* either leave them alone, deactivate them, or move them to the cache,
|
|
* where moving them to the cache has the highest weighting.
|
|
* By forcing some pages into other queues we eventually force the
|
|
* system to balance the queues, potentially recovering other unrelated
|
|
* space from active. The idea is to not force this to happen too
|
|
* often.
|
|
*/
|
|
void
|
|
vm_page_dontneed(vm_page_t m)
|
|
{
|
|
static int dnweight;
|
|
int dnw;
|
|
int head;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
dnw = ++dnweight;
|
|
|
|
/*
|
|
* occassionally leave the page alone
|
|
*/
|
|
if ((dnw & 0x01F0) == 0 ||
|
|
m->queue == PQ_INACTIVE ||
|
|
m->queue - m->pc == PQ_CACHE
|
|
) {
|
|
if (m->act_count >= ACT_INIT)
|
|
--m->act_count;
|
|
return;
|
|
}
|
|
|
|
if (m->dirty == 0)
|
|
vm_page_test_dirty(m);
|
|
|
|
if (m->dirty || (dnw & 0x0070) == 0) {
|
|
/*
|
|
* Deactivate the page 3 times out of 32.
|
|
*/
|
|
head = 0;
|
|
} else {
|
|
/*
|
|
* Cache the page 28 times out of every 32. Note that
|
|
* the page is deactivated instead of cached, but placed
|
|
* at the head of the queue instead of the tail.
|
|
*/
|
|
head = 1;
|
|
}
|
|
_vm_page_deactivate(m, head);
|
|
}
|
|
|
|
/*
|
|
* Grab a page, waiting until we are waken up due to the page
|
|
* changing state. We keep on waiting, if the page continues
|
|
* to be in the object. If the page doesn't exist, allocate it.
|
|
*
|
|
* This routine may block.
|
|
*/
|
|
vm_page_t
|
|
vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
|
|
{
|
|
vm_page_t m;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
|
|
retrylookup:
|
|
if ((m = vm_page_lookup(object, pindex)) != NULL) {
|
|
vm_page_lock_queues();
|
|
if (m->busy || (m->flags & PG_BUSY)) {
|
|
vm_page_flag_set(m, PG_WANTED | PG_REFERENCED);
|
|
VM_OBJECT_UNLOCK(object);
|
|
msleep(m, &vm_page_queue_mtx, PDROP | PVM, "pgrbwt", 0);
|
|
VM_OBJECT_LOCK(object);
|
|
if ((allocflags & VM_ALLOC_RETRY) == 0)
|
|
return (NULL);
|
|
goto retrylookup;
|
|
} else {
|
|
if (allocflags & VM_ALLOC_WIRED)
|
|
vm_page_wire(m);
|
|
vm_page_busy(m);
|
|
vm_page_unlock_queues();
|
|
return m;
|
|
}
|
|
}
|
|
|
|
m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY);
|
|
if (m == NULL) {
|
|
VM_OBJECT_UNLOCK(object);
|
|
VM_WAIT;
|
|
VM_OBJECT_LOCK(object);
|
|
if ((allocflags & VM_ALLOC_RETRY) == 0)
|
|
return NULL;
|
|
goto retrylookup;
|
|
}
|
|
|
|
return m;
|
|
}
|
|
|
|
/*
|
|
* Mapping function for valid bits or for dirty bits in
|
|
* a page. May not block.
|
|
*
|
|
* Inputs are required to range within a page.
|
|
*/
|
|
__inline int
|
|
vm_page_bits(int base, int size)
|
|
{
|
|
int first_bit;
|
|
int last_bit;
|
|
|
|
KASSERT(
|
|
base + size <= PAGE_SIZE,
|
|
("vm_page_bits: illegal base/size %d/%d", base, size)
|
|
);
|
|
|
|
if (size == 0) /* handle degenerate case */
|
|
return (0);
|
|
|
|
first_bit = base >> DEV_BSHIFT;
|
|
last_bit = (base + size - 1) >> DEV_BSHIFT;
|
|
|
|
return ((2 << last_bit) - (1 << first_bit));
|
|
}
|
|
|
|
/*
|
|
* vm_page_set_validclean:
|
|
*
|
|
* Sets portions of a page valid and clean. The arguments are expected
|
|
* to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive
|
|
* of any partial chunks touched by the range. The invalid portion of
|
|
* such chunks will be zero'd.
|
|
*
|
|
* This routine may not block.
|
|
*
|
|
* (base + size) must be less then or equal to PAGE_SIZE.
|
|
*/
|
|
void
|
|
vm_page_set_validclean(vm_page_t m, int base, int size)
|
|
{
|
|
int pagebits;
|
|
int frag;
|
|
int endoff;
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
if (size == 0) /* handle degenerate case */
|
|
return;
|
|
|
|
/*
|
|
* If the base is not DEV_BSIZE aligned and the valid
|
|
* bit is clear, we have to zero out a portion of the
|
|
* first block.
|
|
*/
|
|
if ((frag = base & ~(DEV_BSIZE - 1)) != base &&
|
|
(m->valid & (1 << (base >> DEV_BSHIFT))) == 0)
|
|
pmap_zero_page_area(m, frag, base - frag);
|
|
|
|
/*
|
|
* If the ending offset is not DEV_BSIZE aligned and the
|
|
* valid bit is clear, we have to zero out a portion of
|
|
* the last block.
|
|
*/
|
|
endoff = base + size;
|
|
if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff &&
|
|
(m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0)
|
|
pmap_zero_page_area(m, endoff,
|
|
DEV_BSIZE - (endoff & (DEV_BSIZE - 1)));
|
|
|
|
/*
|
|
* Set valid, clear dirty bits. If validating the entire
|
|
* page we can safely clear the pmap modify bit. We also
|
|
* use this opportunity to clear the PG_NOSYNC flag. If a process
|
|
* takes a write fault on a MAP_NOSYNC memory area the flag will
|
|
* be set again.
|
|
*
|
|
* We set valid bits inclusive of any overlap, but we can only
|
|
* clear dirty bits for DEV_BSIZE chunks that are fully within
|
|
* the range.
|
|
*/
|
|
pagebits = vm_page_bits(base, size);
|
|
m->valid |= pagebits;
|
|
#if 0 /* NOT YET */
|
|
if ((frag = base & (DEV_BSIZE - 1)) != 0) {
|
|
frag = DEV_BSIZE - frag;
|
|
base += frag;
|
|
size -= frag;
|
|
if (size < 0)
|
|
size = 0;
|
|
}
|
|
pagebits = vm_page_bits(base, size & (DEV_BSIZE - 1));
|
|
#endif
|
|
m->dirty &= ~pagebits;
|
|
if (base == 0 && size == PAGE_SIZE) {
|
|
pmap_clear_modify(m);
|
|
vm_page_flag_clear(m, PG_NOSYNC);
|
|
}
|
|
}
|
|
|
|
void
|
|
vm_page_clear_dirty(vm_page_t m, int base, int size)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->dirty &= ~vm_page_bits(base, size);
|
|
}
|
|
|
|
/*
|
|
* vm_page_set_invalid:
|
|
*
|
|
* Invalidates DEV_BSIZE'd chunks within a page. Both the
|
|
* valid and dirty bits for the effected areas are cleared.
|
|
*
|
|
* May not block.
|
|
*/
|
|
void
|
|
vm_page_set_invalid(vm_page_t m, int base, int size)
|
|
{
|
|
int bits;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
bits = vm_page_bits(base, size);
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->valid &= ~bits;
|
|
m->dirty &= ~bits;
|
|
m->object->generation++;
|
|
}
|
|
|
|
/*
|
|
* vm_page_zero_invalid()
|
|
*
|
|
* The kernel assumes that the invalid portions of a page contain
|
|
* garbage, but such pages can be mapped into memory by user code.
|
|
* When this occurs, we must zero out the non-valid portions of the
|
|
* page so user code sees what it expects.
|
|
*
|
|
* Pages are most often semi-valid when the end of a file is mapped
|
|
* into memory and the file's size is not page aligned.
|
|
*/
|
|
void
|
|
vm_page_zero_invalid(vm_page_t m, boolean_t setvalid)
|
|
{
|
|
int b;
|
|
int i;
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
/*
|
|
* Scan the valid bits looking for invalid sections that
|
|
* must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the
|
|
* valid bit may be set ) have already been zerod by
|
|
* vm_page_set_validclean().
|
|
*/
|
|
for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) {
|
|
if (i == (PAGE_SIZE / DEV_BSIZE) ||
|
|
(m->valid & (1 << i))
|
|
) {
|
|
if (i > b) {
|
|
pmap_zero_page_area(m,
|
|
b << DEV_BSHIFT, (i - b) << DEV_BSHIFT);
|
|
}
|
|
b = i + 1;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* setvalid is TRUE when we can safely set the zero'd areas
|
|
* as being valid. We can do this if there are no cache consistancy
|
|
* issues. e.g. it is ok to do with UFS, but not ok to do with NFS.
|
|
*/
|
|
if (setvalid)
|
|
m->valid = VM_PAGE_BITS_ALL;
|
|
}
|
|
|
|
/*
|
|
* vm_page_is_valid:
|
|
*
|
|
* Is (partial) page valid? Note that the case where size == 0
|
|
* will return FALSE in the degenerate case where the page is
|
|
* entirely invalid, and TRUE otherwise.
|
|
*
|
|
* May not block.
|
|
*/
|
|
int
|
|
vm_page_is_valid(vm_page_t m, int base, int size)
|
|
{
|
|
int bits = vm_page_bits(base, size);
|
|
|
|
VM_OBJECT_LOCK_ASSERT(m->object, MA_OWNED);
|
|
if (m->valid && ((m->valid & bits) == bits))
|
|
return 1;
|
|
else
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* update dirty bits from pmap/mmu. May not block.
|
|
*/
|
|
void
|
|
vm_page_test_dirty(vm_page_t m)
|
|
{
|
|
if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) {
|
|
vm_page_dirty(m);
|
|
}
|
|
}
|
|
|
|
int so_zerocp_fullpage = 0;
|
|
|
|
void
|
|
vm_page_cowfault(vm_page_t m)
|
|
{
|
|
vm_page_t mnew;
|
|
vm_object_t object;
|
|
vm_pindex_t pindex;
|
|
|
|
object = m->object;
|
|
pindex = m->pindex;
|
|
vm_page_busy(m);
|
|
|
|
retry_alloc:
|
|
vm_page_remove(m);
|
|
/*
|
|
* An interrupt allocation is requested because the page
|
|
* queues lock is held.
|
|
*/
|
|
mnew = vm_page_alloc(object, pindex, VM_ALLOC_INTERRUPT);
|
|
if (mnew == NULL) {
|
|
vm_page_insert(m, object, pindex);
|
|
vm_page_unlock_queues();
|
|
VM_OBJECT_UNLOCK(object);
|
|
VM_WAIT;
|
|
VM_OBJECT_LOCK(object);
|
|
vm_page_lock_queues();
|
|
goto retry_alloc;
|
|
}
|
|
|
|
if (m->cow == 0) {
|
|
/*
|
|
* check to see if we raced with an xmit complete when
|
|
* waiting to allocate a page. If so, put things back
|
|
* the way they were
|
|
*/
|
|
vm_page_busy(mnew);
|
|
vm_page_free(mnew);
|
|
vm_page_insert(m, object, pindex);
|
|
} else { /* clear COW & copy page */
|
|
if (!so_zerocp_fullpage)
|
|
pmap_copy_page(m, mnew);
|
|
mnew->valid = VM_PAGE_BITS_ALL;
|
|
vm_page_dirty(mnew);
|
|
vm_page_flag_clear(mnew, PG_BUSY);
|
|
}
|
|
}
|
|
|
|
void
|
|
vm_page_cowclear(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
if (m->cow) {
|
|
m->cow--;
|
|
/*
|
|
* let vm_fault add back write permission lazily
|
|
*/
|
|
}
|
|
/*
|
|
* sf_buf_free() will free the page, so we needn't do it here
|
|
*/
|
|
}
|
|
|
|
void
|
|
vm_page_cowsetup(vm_page_t m)
|
|
{
|
|
|
|
mtx_assert(&vm_page_queue_mtx, MA_OWNED);
|
|
m->cow++;
|
|
pmap_page_protect(m, VM_PROT_READ);
|
|
}
|
|
|
|
#include "opt_ddb.h"
|
|
#ifdef DDB
|
|
#include <sys/kernel.h>
|
|
|
|
#include <ddb/ddb.h>
|
|
|
|
DB_SHOW_COMMAND(page, vm_page_print_page_info)
|
|
{
|
|
db_printf("cnt.v_free_count: %d\n", cnt.v_free_count);
|
|
db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count);
|
|
db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count);
|
|
db_printf("cnt.v_active_count: %d\n", cnt.v_active_count);
|
|
db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count);
|
|
db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved);
|
|
db_printf("cnt.v_free_min: %d\n", cnt.v_free_min);
|
|
db_printf("cnt.v_free_target: %d\n", cnt.v_free_target);
|
|
db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min);
|
|
db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target);
|
|
}
|
|
|
|
DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info)
|
|
{
|
|
int i;
|
|
db_printf("PQ_FREE:");
|
|
for (i = 0; i < PQ_L2_SIZE; i++) {
|
|
db_printf(" %d", vm_page_queues[PQ_FREE + i].lcnt);
|
|
}
|
|
db_printf("\n");
|
|
|
|
db_printf("PQ_CACHE:");
|
|
for (i = 0; i < PQ_L2_SIZE; i++) {
|
|
db_printf(" %d", vm_page_queues[PQ_CACHE + i].lcnt);
|
|
}
|
|
db_printf("\n");
|
|
|
|
db_printf("PQ_ACTIVE: %d, PQ_INACTIVE: %d\n",
|
|
vm_page_queues[PQ_ACTIVE].lcnt,
|
|
vm_page_queues[PQ_INACTIVE].lcnt);
|
|
}
|
|
#endif /* DDB */
|