swapctl.2 (2010 09)

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swapctl(2) swapctl(2)

NAME

swapctl - manage and conﬁgure system swap space

SYNOPSIS

#include <sys/swap.h>

int swapctl(int cmd, void * arg);

PARAMETERS

cmd Speciﬁes the operation to be performed, which includes: adding a resource, deleting a resource

reservation, and listing the swap resources.

SC_ADD Add a new swap resource to the system.

SC_LIST List the swap devices on the system. Currently only the primary swap for the

next boot will be listed, if it was conﬁgured by

SC_ADD. See the SC_LIST

Command section below for more details.

SC_REMOVE Remove the swap device conﬁgured on the system. Currently the ﬁle system

swap removal is not supported. See the SC_REMOVE Command section

below for more details.

arg Speciﬁes a pointer to a structure and is dependent on the type of command speciﬁed by the

cmd parameter. See DESCRIPTION below for more information.

DESCRIPTION

The

swapctl() system call manages system swap space by adding or deleting swap resources or return-

ing information about swap resources. The cmd parameter determines the value of the arg parameter.

Each of these commands accepts/returns information in a structure pointed to by the arg parameter. The

following sections discuss the information that should be passed in to the system call. They also explain

the information contained in these structures after a successful return.

The SC_ADD Command

For the

SC_ADD command, arg parameter is a pointer to the swapres structure with some of the follow-

ing members, depending on which type of swap is being conﬁgured:

swapctl_flags_t sr_flag

char * sr_name

int64_t sr_start

int64_t sr_length

int64_t sr_priority

int64_t sr_min

int64_t sr_lim

int64_t sr_res

where the ﬁelds are as follows:

sr_flag is one of the following:

•

SW_PRIMARY | SW_NEXTBOOT (primary swap device for the next boot)

•

SW_DEVICE (swap device for current boot)

•

SW_FILESYS (swap ﬁle system for the current boot)

See the ﬂag ﬁeld description below for details on the usage.

*sr_name Provides the pathname of the resource that is being added.

sr_start Speciﬁes, in 1 kilobyte blocks, the starting offset of the swap resource area.

sr_length Speciﬁes, in 1 kilobyte blocks, the length of the swap area. Value of 0 means

conﬁgure the entire device, starting from the

sr_start offset.

sr_priority Indicates the order in which the swap space from the device or ﬁle system is used.

It has a range of 0 (highest) to 10 (lowest). Swap space is taken from the lower-

numbered systems ﬁrst.

sr_min (Needed for ﬁle system swap only.) Indicates the minimum number of ﬁle system

blocks the swap system will take from the ﬁle system.

HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1

Summary of content (6 pages)

PAGE 1
swapctl(2) swapctl(2) NAME swapctl - manage and configure system swap space SYNOPSIS #include int swapctl(int cmd, void * arg); PARAMETERS cmd Specifies the operation to be performed, which includes: adding a resource, deleting a resource reservation, and listing the swap resources. arg SC_ADD Add a new swap resource to the system. SC_LIST List the swap devices on the system. Currently only the primary swap for the next boot will be listed, if it was configured by SC_ADD.
PAGE 2
swapctl(2) swapctl(2) sr_lim (Needed for file system swap only.) Indicates the maximum number of file system blocks the swap system is allowed to take from the file system. sr_res (Needed for file system swap only.) Indicates the number of file system blocks that are reserved for swap system use only. For the SC_ADD command, depending on the sr_flag type, the following members of swapres structure need to be passed in.
PAGE 3
swapctl(2) swapctl(2) The SC_LIST Command For the SC_LIST command, arg parameter is a pointer to the swaptable structure with following members: int swt_n swapctl_flags_t swt_flag struct swapent swt_ent [] where: swt_n Specifies the maximum entries that will be returned by swapctl(). swt_ent Is an array of swt_n swapents. Currently the SC_LIST command can be used to list the primary swap configured for next boot, so the array size for the swapent structures is 1.
PAGE 4
swapctl(2) swapctl(2) [EIO] Unable to read or write to the kernel registry services (see krs (5)). [EFAULT] Specifies that the structure pointed to by the arg parameter or swt_ent field of swaptable_t struct, or one of the fields sr_name or ste_path is outside the allocated address space. [EINVAL] Invalid input parameter passed in.
PAGE 5
swapctl(2) swapctl(2) exit(1); } /* list the swap device configured above */ swent.ste_path = path; swt.swt_n = 1; swt.swt_flags = SW_PRIMARY | SW_NEXTBOOT; swt.swt_ent = &swent; rv = swapctl(SC_LIST, (void *)&swt); if (rv != 1) { /* returns the number of swap devices returned */ printf("swapctl/SC_LIST returned: %d \n", rv); perror("swapctl/SC_LIST failed"); exit(2); } printf("Primary swap for next boot: %s \n", swent.ste_path); /* Remove the above configured primary swap */ swp.
PAGE 6
(Notes) A (Notes) sA 6 Hewlett-Packard Company −1− HP-UX 11i Version 3: September 2010