include/linux/threads.h

Source file repositories/reference/linux-study-clean/include/linux/threads.h

File Facts

System
Linux kernel
Corpus path
include/linux/threads.h
Extension
.h
Size
1338 bytes
Lines
47
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

#ifndef _LINUX_THREADS_H
#define _LINUX_THREADS_H


/*
 * The default limit for the nr of threads is now in
 * /proc/sys/kernel/threads-max.
 */

/*
 * Maximum supported processors.  Setting this smaller saves quite a
 * bit of memory.  Use nr_cpu_ids instead of this except for static bitmaps.
 */
#ifndef CONFIG_NR_CPUS
/* FIXME: This should be fixed in the arch's Kconfig */
#define CONFIG_NR_CPUS	1
#endif

/* Places which use this should consider cpumask_var_t. */
#define NR_CPUS		CONFIG_NR_CPUS

#define MIN_THREADS_LEFT_FOR_ROOT 4

/*
 * This controls the default maximum pid allocated to a process
 */
#define PID_MAX_DEFAULT (IS_ENABLED(CONFIG_BASE_SMALL) ? 0x1000 : 0x8000)

/*
 * A maximum of 4 million PIDs should be enough for a while.
 * [NOTE: PID/TIDs are limited to 2^30 ~= 1 billion, see FUTEX_TID_MASK.]
 */
#define PID_MAX_LIMIT (IS_ENABLED(CONFIG_BASE_SMALL) ? PAGE_SIZE * 8 : \
	(sizeof(long) > 4 ? 4 * 1024 * 1024 : PID_MAX_DEFAULT))

/*
 * Define a minimum number of pids per cpu.  Heuristically based
 * on original pid max of 32k for 32 cpus.  Also, increase the
 * minimum settable value for pid_max on the running system based
 * on similar defaults.  See kernel/pid.c:pid_idr_init() for details.
 */
#define PIDS_PER_CPU_DEFAULT	1024
#define PIDS_PER_CPU_MIN	8

#endif

Annotation

Implementation Notes