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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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72680a191b
On a system with a substantial number of processors, the early default pid_max of 32k will not be enough. A system with 1664 CPU's, there are 25163 processes started before the login prompt. It's estimated that with 2048 CPU's we will pass the 32k limit. With 4096, we'll reach that limit very early during the boot cycle, and processes would stall waiting for an available pid. This patch increases the early maximum number of pids available, and increases the minimum number of pids that can be set during runtime. [akpm@linux-foundation.org: fix warnings] Signed-off-by: Hedi Berriche <hedi@sgi.com> Signed-off-by: Mike Travis <travis@sgi.com> Signed-off-by: Robin Holt <holt@sgi.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Pavel Machek <pavel@ucw.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Cc: Greg KH <gregkh@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: John Stoffel <john@stoffel.org> Cc: Jack Steiner <steiner@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
46 lines
1.2 KiB
C
46 lines
1.2 KiB
C
#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 2^29 ~= 500+ million, see futex.h.]
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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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