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9c40365a65
The futex UAPI changed back in commit 76b81e2b0e ("[PATCH] lightweight
robust futexes updates 2"), which landed in v2.6.17: FUTEX_TID_MASK is now
0x3fffffff instead of 0x1fffffff. Update the corresponding comment in
include/linux/threads.h.
Documentation mentions that only the lower 29 bits are available for TID
storage, but as the UAPI header released the bit already via
FUTEX_TID_MASK, this is moot as well. Fix it up.
[ tglx: Fixed up documentation ]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200302112939.8068-1-jannh@google.com
46 lines
1.3 KiB
C
46 lines
1.3 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_THREADS_H
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#define _LINUX_THREADS_H
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/*
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* The default limit for the nr of threads is now in
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* /proc/sys/kernel/threads-max.
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*/
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/*
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* Maximum supported processors. Setting this smaller saves quite a
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* bit of memory. Use nr_cpu_ids instead of this except for static bitmaps.
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*/
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#ifndef CONFIG_NR_CPUS
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/* FIXME: This should be fixed in the arch's Kconfig */
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#define CONFIG_NR_CPUS 1
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#endif
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/* Places which use this should consider cpumask_var_t. */
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#define NR_CPUS CONFIG_NR_CPUS
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#define MIN_THREADS_LEFT_FOR_ROOT 4
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/*
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* This controls the default maximum pid allocated to a process
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*/
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#define PID_MAX_DEFAULT (CONFIG_BASE_SMALL ? 0x1000 : 0x8000)
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/*
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* A maximum of 4 million PIDs should be enough for a while.
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* [NOTE: PID/TIDs are limited to 2^30 ~= 1 billion, see FUTEX_TID_MASK.]
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*/
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#define PID_MAX_LIMIT (CONFIG_BASE_SMALL ? PAGE_SIZE * 8 : \
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(sizeof(long) > 4 ? 4 * 1024 * 1024 : PID_MAX_DEFAULT))
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/*
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* Define a minimum number of pids per cpu. Heuristically based
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* on original pid max of 32k for 32 cpus. Also, increase the
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* minimum settable value for pid_max on the running system based
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* on similar defaults. See kernel/pid.c:pidmap_init() for details.
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*/
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#define PIDS_PER_CPU_DEFAULT 1024
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#define PIDS_PER_CPU_MIN 8
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#endif
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