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b94221f3b2
This reverts hrev54120 and instead adds the commonly supported MAP_NORESERVE flag to request overcommit. Using PROT_NONE for overcommit is problematic as the protection of individual pages can still be changed via mprotect to make them accessible, but that won't change the commitment. An application using such a pattern may then unexpectedly run into out of memory conditions on random writes into the address space. With MAP_NORESERVE the overcommit can explicitly be requested by applications that want to reserve address space without producing memory pressure. Change-Id: Id213d2245c5e23103e8e0857f7902e0cd8a2c65d Reviewed-on: https://review.haiku-os.org/c/haiku/+/2611 Reviewed-by: waddlesplash <waddlesplash@gmail.com> Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
62 lines
1.5 KiB
C
62 lines
1.5 KiB
C
/*
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* Copyright 2008-2012 Haiku, Inc. All Rights Reserved.
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* Distributed under the terms of the MIT License.
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*/
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#ifndef _SYS_MMAN_H
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#define _SYS_MMAN_H
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#include <sys/cdefs.h>
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#include <sys/types.h>
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/* memory protection for mmap() and others; assignment compatible with
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B_{READ,WRITE,EXECUTE}_AREA */
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#define PROT_READ 0x01
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#define PROT_WRITE 0x02
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#define PROT_EXEC 0x04
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#define PROT_NONE 0x00
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/* mmap() flags */
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#define MAP_SHARED 0x01 /* changes are seen by others */
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#define MAP_PRIVATE 0x02 /* changes are only seen by caller */
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#define MAP_FIXED 0x04 /* require mapping to specified addr */
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#define MAP_ANONYMOUS 0x08 /* no underlying object */
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#define MAP_ANON MAP_ANONYMOUS
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#define MAP_NORESERVE 0x10 /* don't commit memory */
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/* mmap() error return code */
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#define MAP_FAILED ((void*)-1)
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/* msync() flags */
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#define MS_ASYNC 0x01
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#define MS_SYNC 0x02
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#define MS_INVALIDATE 0x04
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/* posix_madvise() values */
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#define POSIX_MADV_NORMAL 1
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#define POSIX_MADV_SEQUENTIAL 2
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#define POSIX_MADV_RANDOM 3
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#define POSIX_MADV_WILLNEED 4
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#define POSIX_MADV_DONTNEED 5
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__BEGIN_DECLS
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void* mmap(void* address, size_t length, int protection, int flags,
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int fd, off_t offset);
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int munmap(void* address, size_t length);
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int mprotect(void* address, size_t length, int protection);
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int msync(void* address, size_t length, int flags);
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int posix_madvise(void* address, size_t length, int advice);
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int shm_open(const char* name, int openMode, mode_t permissions);
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int shm_unlink(const char* name);
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__END_DECLS
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#endif /* _SYS_MMAN_H */
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