預設 PID 最大編號為 32768。
cat /proc/sys/kernel/pid_max
32768
或者
sysctl kernel.pid_max
kernel.pid_max = 32768
現在,我想更改這個號碼...但我不能。好吧,實際上我可以將其更改為更低的值或相同的值。例如:
linux-6eea:~ # sysctl -w kernel.pid_max=32768
kernel.pid_max = 32768
但我不能對大於 32768 的值執行此操作。
linux-6eea:~ # sysctl -w kernel.pid_max=32769
error: "Invalid argument" setting key "kernel.pid_max"
有任何想法嗎 ?
PS:我的核心是 Linux linux-6eea 3.0.101-0.35-pae #1 SMP Wed Jul 9 11:43:04 UTC 2014 (c36987d) i686 i686 i386 GNU/Linux
答案1
對於 32 位元系統,該值最多只能擴展到理論最大值 32768;對於 64 位元系統,該值最多只能擴展到 4194304。
從man 5 proc
:
/proc/sys/kernel/pid_max This file (new in Linux 2.5) specifies the value at which PIDs wrap around (i.e., the value in this file is one greater than the maximum PID). The default value for this file, 32768, results in the same range of PIDs as on earlier kernels. On 32-bit platfroms, 32768 is the maximum value for pid_max. On 64-bit systems, pid_max can be set to any value up to 2^22 (PID_MAX_LIMIT, approximately 4 million).