8f60c087e6
striping to a per device round-robin algorithm. Because of the policy of not attempting to retain previous swap allocation on page-out, this means that a newly added swap device almost instantly takes its 1/N share of the I/O load but it takes somewhat longer for it to assume it's 1/N share of the pages if there is plenty of space on the other devices. Change the 8G total swapspace limitation to 8G per device instead by using a per device blist rather than one global blist. This reduces the memory footprint by 75% (typically a couple hundred kilobytes) for the common case with one swapdevice but NSWAPDEV=4. Remove the compile time constant limit of number of swap devices, there is no limit now. Instead of a fixed size array, store the per swapdev structure in a TAILQ. Total swap space is still addressed by a 32 bit page number and therefore the upper limit is now 2^42 bytes = 16TB (for i386). We still do not allocate the first page of each device in order to give some amount of protection to any bsdlabel at the start of the device. A new device is appended after the existing devices in the swap space, no attempt is made to fill in holes left behind by swapoff (this can trivially be changed should it ever become a problem). The sysctl vm.nswapdev now reflects the number of currently configured swap devices. Rename vm_swap_size to swap_pager_avail for consistency with other exported names. Change argument type for vm_proc_swapin_all() and swap_pager_isswapped() to be a struct swdevt pointer rather than an index. Not changed: we are still using blists to manage the free space, but since the swapspace is no longer fragmented by the striping different resource managers might fare better.
66 lines
2.7 KiB
C
66 lines
2.7 KiB
C
/*
|
|
* Copyright (c) 1990 University of Utah.
|
|
* Copyright (c) 1991 The Regents of the University of California.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* the Systems Programming Group of the University of Utah Computer
|
|
* Science Department.
|
|
*
|
|
* 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.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 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 REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
|
|
*
|
|
* from: @(#)swap_pager.h 7.1 (Berkeley) 12/5/90
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
/*
|
|
* Modifications to the block allocation data structure by John S. Dyson
|
|
* 18 Dec 93.
|
|
*/
|
|
|
|
#ifndef _VM_SWAP_PAGER_H_
|
|
#define _VM_SWAP_PAGER_H_ 1
|
|
|
|
#ifdef _KERNEL
|
|
|
|
extern int swap_pager_full;
|
|
extern int swap_pager_avail;
|
|
|
|
struct swdevt;
|
|
void swap_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
|
|
void swap_pager_copy(vm_object_t, vm_object_t, vm_pindex_t, int);
|
|
void swap_pager_freespace(vm_object_t, vm_pindex_t, vm_size_t);
|
|
void swap_pager_swap_init(void);
|
|
int swap_pager_isswapped(vm_object_t, struct swdevt *);
|
|
int swap_pager_reserve(vm_object_t, vm_pindex_t, vm_size_t);
|
|
void swap_pager_status(int *total, int *used);
|
|
|
|
#endif /* _KERNEL */
|
|
#endif /* _VM_SWAP_PAGER_H_ */
|