Index: doc/src/sgml/runtime.sgml
===================================================================
RCS file: /projects/cvsroot/pgsql-server/doc/src/sgml/runtime.sgml,v
retrieving revision 1.200
diff -c -w -r1.200 runtime.sgml
*** doc/src/sgml/runtime.sgml	17 Aug 2003 22:19:10 -0000	1.200
--- doc/src/sgml/runtime.sgml	21 Aug 2003 16:57:43 -0000
***************
*** 3068,3081 ****
         </para>
  
         <para>
!         Linux has poor default memory overcommit behavior.  Rather than
!         failing if it can not reserve enough memory, it returns success, 
!         but later fails when the memory can't be mapped and terminates 
!         the application with <literal>kill -9</>.  To prevent unpredictable 
!         process termination, use:
  <programlisting>
  sysctl -w vm.overcommit_memory=3
  </programlisting>
          Note, you will need enough swap space to cover all your memory needs.
         </para>
        </listitem>
--- 3068,3125 ----
         </para>
  
         <para>
! 	Linux kernel version 2.4.* has poor default memory overcommit 
! 	behavior, which can result in the postmaster being killed by the 
! 	kernel due to memory demands by another process if the system 
! 	runs out of memory.
! 	</para>
! 
!        <para>
! 	The symptom of this occuring is a kernel message looking like 
! 	this (consult your system documentation and configuration on 
! 	where to look for such a message):
! <programlisting>
!  Out of Memory: Killed process 12345 (postmaster). 
! </programlisting>
! 	</para>
! 
!        <para>
! 	To avoid this situation, run postgres on a machine where you 
! 	can be sure that other processes will not run the machine out 
! 	of memory. If your kernel supports strict and/or paranoid modes 
! 	of overcommit handling, you can also relieve this problem by 
! 	altering the system's default behaviour. This can be determined 
! 	by examining the function <varname>vm_enough_memory</>
! 	in the file <filename>mm/mmap.c</>in the kernel source. 
! 	If this file reveals that strict and/or paranoid modes are 
! 	supported by your kernel, turn one of these modes on by using
! <programlisting>
! sysctl -w vm.overcommit_memory=2
! </programlisting>
! 	 for strict mode or
  <programlisting>
  sysctl -w vm.overcommit_memory=3
  </programlisting>
+ 	for paranoid mode, or placing an equivalent entry in 
+ 	<filename>/etc/sysctl.conf</>.
+ 	</para>
+ 
+        <para>
+ 	Warning: using these settings in a kernel which does not support 
+ 	these modes will almost certainly increase the danger of the 
+ 	kernel killing the postmaster, rather than reducing it. 
+ 	If in any doubt, consult a kernel expert or your kernel vendor.
+ 	</para>
+ 
+        <para>
+ 	These modes are expected to be supported in all 2.6 and later 
+ 	kernels. Some vendor 2.4 kernels may also support these modes. 
+ 	However, it is known that some vendor documents suggest that 
+ 	they support them while examination of the kernel source reveals 
+ 	that they do not.
+ 	</para>
+ 
+        <para>
          Note, you will need enough swap space to cover all your memory needs.
         </para>
        </listitem>