_PHOLD (9)

Leading comments

Copyright (c) 2015 Mark Johnston <markj@FreeBSD.org>

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(The comments found at the beginning of the groff file "man9/_PHOLD.9freebsd".)

NAME

PHOLD - hold a process

SYNOPSIS

In sys/proc.h Fn PHOLD struct proc *p Fn _PHOLD struct proc *p Fn PRELE struct proc *p Fn _PRELE struct proc *p Fn PROC_ASSERT_HELD struct proc *p Fn PROC_ASSERT_NOT_HELD struct proc *p

DESCRIPTION

The Fn PHOLD macro increments the hold count of a process, and the Fn PRELE macro decrements the hold count of a process.

If a process with a non-zero hold count attempts to exit, it will sleep until its hold count has reached zero before the kernel begins releasing resources associated with the process. Once a process has started exiting, it is invalid to increase its hold count. Thus, callers must not attempt to hold a process that has the P_WEXIT flag set. The VM daemon will not swap out the kernel stack of a thread belonging to a process with a non-zero hold count.

The Fn _PHOLD and Fn _PRELE macros are identical to Fn PHOLD and Fn PRELE , except that they must be called with the process lock held.

AUTHORS

This manual page was written by An Mark Johnston Aq Mt markj@FreeBSD.org .