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freebsd-skq/sys/vm/pmap.h
Alan Cox 51321f7c31 Significantly reduce the cost, i.e., run time, of calls to madvise(..., 
MADV_DONTNEED) and madvise(..., MADV_FREE).  Specifically, introduce a new
pmap function, pmap_advise(), that operates on a range of virtual addresses
within the specified pmap, allowing for a more efficient implementation of
MADV_DONTNEED and MADV_FREE.  Previously, the implementation of
MADV_DONTNEED and MADV_FREE relied on per-page pmap operations, such as
pmap_clear_reference().  Intuitively, the problem with this implementation
is that the pmap-level locks are acquired and released and the page table
traversed repeatedly, once for each resident page in the range
that was specified to madvise(2).  A more subtle flaw with the previous
implementation is that pmap_clear_reference() would clear the reference bit
on all mappings to the specified page, not just the mapping in the range
specified to madvise(2).

Since our malloc(3) makes heavy use of madvise(2), this change can have a
measureable impact.  For example, the system time for completing a parallel
"buildworld" on a 6-core amd64 machine was reduced by about 1.5% to 2.0%.

Note: This change only contains pmap_advise() implementations for a subset
of our supported architectures.  I will commit implementations for the
remaining architectures after further testing.  For now, a stub function is
sufficient because of the advisory nature of pmap_advise().

Discussed with: jeff, jhb, kib
Tested by:      pho (i386), marcel (ia64)
Sponsored by:   EMC / Isilon Storage Division
2013-08-29 15:49:05 +00:00

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/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* 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 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: @(#)pmap.h 8.1 (Berkeley) 6/11/93
*
*
* Copyright (c) 1987, 1990 Carnegie-Mellon University.
* All rights reserved.
*
* Author: Avadis Tevanian, Jr.
*
* Permission to use, copy, modify and distribute this software and
* its documentation is hereby granted, provided that both the copyright
* notice and this permission notice appear in all copies of the
* software, derivative works or modified versions, and any portions
* thereof, and that both notices appear in supporting documentation.
*
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* Carnegie Mellon requests users of this software to return to
*
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
* School of Computer Science
* Carnegie Mellon University
* Pittsburgh PA 15213-3890
*
* any improvements or extensions that they make and grant Carnegie the
* rights to redistribute these changes.
*
* $FreeBSD$
*/
/*
* Machine address mapping definitions -- machine-independent
* section. [For machine-dependent section, see "machine/pmap.h".]
*/
#ifndef _PMAP_VM_
#define _PMAP_VM_
/*
* Each machine dependent implementation is expected to
* keep certain statistics. They may do this anyway they
* so choose, but are expected to return the statistics
* in the following structure.
*/
struct pmap_statistics {
long resident_count; /* # of pages mapped (total) */
long wired_count; /* # of pages wired */
};
typedef struct pmap_statistics *pmap_statistics_t;
/*
* Each machine-dependent implementation is required to provide:
*
* vm_memattr_t pmap_page_get_memattr(vm_page_t);
* boolean_t pmap_page_is_mapped(vm_page_t);
* boolean_t pmap_page_is_write_mapped(vm_page_t);
* void pmap_page_set_memattr(vm_page_t, vm_memattr_t);
*/
#include <machine/pmap.h>
#ifdef _KERNEL
struct thread;
/*
* Updates to kernel_vm_end are synchronized by the kernel_map's system mutex.
*/
extern vm_offset_t kernel_vm_end;
void pmap_activate(struct thread *td);
void pmap_advise(pmap_t pmap, vm_offset_t sva, vm_offset_t eva,
int advice);
void pmap_align_superpage(vm_object_t, vm_ooffset_t, vm_offset_t *,
vm_size_t);
void pmap_change_wiring(pmap_t, vm_offset_t, boolean_t);
void pmap_clear_modify(vm_page_t m);
void pmap_clear_reference(vm_page_t m);
void pmap_copy(pmap_t, pmap_t, vm_offset_t, vm_size_t, vm_offset_t);
void pmap_copy_page(vm_page_t, vm_page_t);
void pmap_copy_pages(vm_page_t ma[], vm_offset_t a_offset,
vm_page_t mb[], vm_offset_t b_offset, int xfersize);
void pmap_enter(pmap_t, vm_offset_t, vm_prot_t, vm_page_t,
vm_prot_t, boolean_t);
void pmap_enter_object(pmap_t pmap, vm_offset_t start,
vm_offset_t end, vm_page_t m_start, vm_prot_t prot);
void pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m,
vm_prot_t prot);
vm_paddr_t pmap_extract(pmap_t pmap, vm_offset_t va);
vm_page_t pmap_extract_and_hold(pmap_t pmap, vm_offset_t va,
vm_prot_t prot);
void pmap_growkernel(vm_offset_t);
void pmap_init(void);
boolean_t pmap_is_modified(vm_page_t m);
boolean_t pmap_is_prefaultable(pmap_t pmap, vm_offset_t va);
boolean_t pmap_is_referenced(vm_page_t m);
vm_offset_t pmap_map(vm_offset_t *, vm_paddr_t, vm_paddr_t, int);
int pmap_mincore(pmap_t pmap, vm_offset_t addr,
vm_paddr_t *locked_pa);
void pmap_object_init_pt(pmap_t pmap, vm_offset_t addr,
vm_object_t object, vm_pindex_t pindex, vm_size_t size);
boolean_t pmap_page_exists_quick(pmap_t pmap, vm_page_t m);
void pmap_page_init(vm_page_t m);
int pmap_page_wired_mappings(vm_page_t m);
int pmap_pinit(pmap_t);
void pmap_pinit0(pmap_t);
void pmap_protect(pmap_t, vm_offset_t, vm_offset_t, vm_prot_t);
void pmap_qenter(vm_offset_t, vm_page_t *, int);
void pmap_qremove(vm_offset_t, int);
void pmap_release(pmap_t);
void pmap_remove(pmap_t, vm_offset_t, vm_offset_t);
void pmap_remove_all(vm_page_t m);
void pmap_remove_pages(pmap_t);
void pmap_remove_write(vm_page_t m);
void pmap_sync_icache(pmap_t, vm_offset_t, vm_size_t);
boolean_t pmap_ts_referenced(vm_page_t m);
void pmap_zero_page(vm_page_t);
void pmap_zero_page_area(vm_page_t, int off, int size);
void pmap_zero_page_idle(vm_page_t);
#define pmap_resident_count(pm) ((pm)->pm_stats.resident_count)
#define pmap_wired_count(pm) ((pm)->pm_stats.wired_count)
#endif /* _KERNEL */
#endif /* _PMAP_VM_ */
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