Albert Cahalan (
14 Jul 2003 00:17:02 -0400

A few things have changed since PID_MAX_DEFAULT
was set to 0x8000. It's now adjustable via the
/proc/sys/kernel/pid_max file. An app, /bin/ps,
now reads this file to determine column width
for PID, PPID, PGID, SESS, LWP, and so on.

The common-case Linux box is best served by a
value that keeps /bin/ps PID columns narrow,
allowing for more space elsewhere. The following
patch gives 4-digit PID values as a default.

diff -Naurd old/include/linux/threads.h new/include/linux/threads.h
--- old/include/linux/threads.h 2003-07-12 19:01:14.000000000 -0400
+++ new/include/linux/threads.h 2003-07-12 19:03:34.000000000 -0400
@@ -25,7 +25,7 @@
* This controls the default maximum pid allocated to a process
-#define PID_MAX_DEFAULT 0x8000
+#define PID_MAX_DEFAULT 10000

* A maximum of 4 million PIDs should be enough for a while:

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