ec492b13f1
Upon each execve, we allocate a KVA range for use in copying data to the new image. Pages must be faulted into the range, and when the range is freed, the backing pages are freed and their mappings are destroyed. This is a lot of needless overhead, and the exec_map management becomes a bottleneck when many CPUs are executing execve concurrently. Moreover, the number of available ranges is fixed at 16, which is insufficient on large systems and potentially excessive on 32-bit systems. The new allocator reduces overhead by making exec_map allocations persistent. When a range is freed, pages backing the range are marked clean and made easy to reclaim. With this change, the exec_map is sized based on the number of CPUs. Reviewed by: kib MFC after: 1 month Differential Revision: https://reviews.freebsd.org/D8921
81 lines
3.3 KiB
C
81 lines
3.3 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. 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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* 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_kern.h 8.1 (Berkeley) 6/11/93
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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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* $FreeBSD$
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*/
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#ifndef _VM_VM_KERN_H_
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#define _VM_VM_KERN_H_
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/* Kernel memory management definitions. */
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extern vm_map_t kernel_map;
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extern vm_map_t exec_map;
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extern vm_map_t pipe_map;
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extern struct vmem *kernel_arena;
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extern struct vmem *kmem_arena;
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extern struct vmem *buffer_arena;
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extern struct vmem *transient_arena;
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extern struct vmem *memguard_arena;
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extern vm_offset_t swapbkva;
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extern u_long vm_kmem_size;
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extern u_int exec_map_entries;
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extern u_int exec_map_entry_size;
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#endif /* _VM_VM_KERN_H_ */
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