119 lines
3.4 KiB
Groff
119 lines
3.4 KiB
Groff
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.\"
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.\" Copyright (c) 2003 Bruce M Simpson <bms@spc.org>
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.\" All rights reserved.
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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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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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.\" $FreeBSD$
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.\"
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.Dd July 19, 2003
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.Dt vm_map_lock 9
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.Sh NAME
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.Nm vm_map_lock ,
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.Nm vm_map_unlock ,
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.Nm vm_map_lock_read ,
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.Nm vm_map_unlock_read ,
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.Nm vm_map_trylock ,
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.Nm vm_map_trylock_read ,
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.Nm vm_map_lock_upgrade ,
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.Nm vm_map_lock_downgrade
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.Nd vm_map locking macros
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.Sh SYNOPSIS
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.In sys/param.h
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.In vm/vm.h
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.In vm/vm_map.h
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.Ft void
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.Fn vm_map_lock "vm_map_t map"
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.Ft void
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.Fn vm_map_unlock "vm_map_t map"
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.Ft void
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.Fn vm_map_lock_read "vm_map_t map"
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.Ft void
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.Fn vm_map_unlock_read "vm_map_t map"
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.Ft int
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.Fn vm_map_trylock "vm_map_t map"
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.Ft int
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.Fn vm_map_trylock_read "vm_map_t map"
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.Ft int
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.Fn vm_map_lock_upgrade "vm_map_t map"
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.Ft int
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.Fn vm_map_lock_downgrade "vm_map_t map"
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.Sh DESCRIPTION
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The
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.Fn vm_map_lock
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macro obtains an exclusive lock on
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.Fa map .
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.Pp
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The
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.Fn vm_map_unlock
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macro releases an exclusive lock on
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.Fa map .
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.Pp
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The
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.Fn vm_map_lock_read
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macro obtains a read-lock on
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.Fa map .
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Currently this is implemented as an exclusive lock.
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.Pp
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The
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.Fn vm_map_unlock_read
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macro releases a read-lock on
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.Fa map .
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.Pp
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The
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.Fn vm_map_trylock
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macro attempts to obtain an exclusive lock on
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.Fa map .
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It returns FALSE if the lock cannot be immediately acquired;
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otherwise return TRUE with the lock acquired.
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.Pp
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The
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.Fn vm_map_trylock_read
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macro attempts to obtain a read-lock on
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.Fa map .
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It returns FALSE if the lock cannot be immediately acquired;
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otherwise return TRUE with the lock acquired.
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Currently this is implemented as an exclusive lock.
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.Pp
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The
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.Fn vm_map_lock_upgrade
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macro attempts to atomically upgrade a read-lock on
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.Fa map
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to an exclusive lock.
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As read-locks are currently implemented as exclusive locks,
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this macro is a no-op.
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.Pp
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The
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.Fn vm_map_lock_downgrade
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macro attempts to downgrade an exclusive lock on
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.Fa map
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to a read-lock.
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As read-locks are currently implemented as exclusive locks,
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this macro is a no-op.
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.Sh IMPLEMENTATION NOTES
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Currently, all of the locking macros implement their locks as sleep locks.
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.Sh SEE ALSO
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.Xr vm_map 9
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.Sh AUTHORS
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This man page was written by
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.An Bruce M Simpson Aq bms@spc.org .
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