KGDB_ROUNDUP_CPUS(9) KGDB Internals KGDB_ROUNDUP_CPUS(9)NAME
kgdb_roundup_cpus - Get other CPUs into a holding pattern
SYNOPSIS
void kgdb_roundup_cpus(unsigned long flags);
ARGUMENTS
flags
Current IRQ state
DESCRIPTION
On SMP systems, we need to get the attention of the other CPUs and get them into a known state. This should do what is needed to get the
other CPUs to call kgdb_wait. Note that on some arches, the NMI approach is not used for rounding up all the CPUs. For example, in case of
MIPS, smp_call_function is used to roundup CPUs. In this case, we have to make sure that interrupts are enabled before calling
smp_call_function. The argument to this function is the flags that will be used when restoring the interrupts. There is local_irq_save call
before kgdb_roundup_cpus.
On non-SMP systems, this is not called.
AUTHORS
Jason Wessel <jason.wessel@windriver.com>
Author.
Tom Rini <trini@kernel.crashing.org>
Author.
Amit S. Kale <amitkale@linsyssoft.com>
Author.
COPYRIGHT Kernel Hackers Manual 2.6. July 2010 KGDB_ROUNDUP_CPUS(9)
Check Out this Related Man Page
CHCPU(8) System Administration CHCPU(8)NAME
chcpu - configure CPUs
SYNOPSIS
chcpu -c|-d|-e|-g cpu-list
chcpu -p mode
chcpu -r|-h|-V
DESCRIPTION
chcpu can modify the state of CPUs. It can enable or disable CPUs, scan for new CPUs, change the CPU dispatching mode of the underlying
hypervisor, and request CPUs from the hypervisor (configure) or return CPUs to the hypervisor (deconfigure).
Some options have a cpu-list argument. Use this argument to specify a comma-separated list of CPUs. The list can contain individual CPU
addresses or ranges of addresses. For example, 0,5,7,9-11 makes the command applicable to the CPUs with the addresses 0, 5, 7, 9, 10, and
11.
OPTIONS -c, --configure cpu-list
Configure the specified CPUs. Configuring a CPU means that the hypervisor takes a CPU from the CPU pool and assigns it to the vir-
tual hardware on which your kernel runs.
-d, --disable cpu-list
Disable the specified CPUs. Disabling a CPU means that the kernel sets it offline.
-e, --enable cpu-list
Enable the specified CPUs. Enabling a CPU means that the kernel sets it online. A CPU must be configured, see -c, before it can be
enabled.
-g, --deconfigure cpu-list
Deconfigure the specified CPUs. Deconfiguring a CPU means that the hypervisor removes the CPU from the virtual hardware on which
the Linux instance runs and returns it to the CPU pool. A CPU must be offline, see -d, before it can be deconfigured.
-p, --dispatch mode
Set the CPU dispatching mode (polarization). This option has an effect only if your hardware architecture and hypervisor support
CPU polarization. Available modes are:
horizontal The workload is spread across all available CPUs.
vertical The workload is concentrated on few CPUs.
-r, --rescan
Trigger a rescan of CPUs. After a rescan, the Linux kernel recognizes the new CPUs. Use this option on systems that do not auto-
matically detect newly attached CPUs.
-V, --version
Display version information and exit.
-h, --help
Display help text and exit.
RETURN CODES
chcpu has the following return codes:
0 success
1 failure
64 partial success
AUTHOR
Heiko Carstens <heiko.carstens@de.ibm.com>
COPYRIGHT
Copyright IBM Corp. 2011
SEE ALSO lscpu(1)AVAILABILITY
The chcpu command is part of the util-linux package and is available from Linux Kernel Archive <https://www.kernel.org/pub/linux/utils
/util-linux/>.
util-linux July 2014 CHCPU(8)