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| -rw-r--r-- | winsup/doc/setup-net.sgml | 1 | ||||
| -rw-r--r-- | winsup/doc/setup2.sgml | 68 |
2 files changed, 69 insertions, 0 deletions
diff --git a/winsup/doc/setup-net.sgml b/winsup/doc/setup-net.sgml index cc40f31..5474392 100644 --- a/winsup/doc/setup-net.sgml +++ b/winsup/doc/setup-net.sgml @@ -10,6 +10,7 @@ Follow the instructions on each screen to install Cygwin.</para> </sect1> DOCTOOL-INSERT-setup-env +DOCTOOL-INSERT-setup-maxmem DOCTOOL-INSERT-ntsec DOCTOOL-INSERT-setup-files </chapter> diff --git a/winsup/doc/setup2.sgml b/winsup/doc/setup2.sgml index 4b2ecf6..592a25d 100644 --- a/winsup/doc/setup2.sgml +++ b/winsup/doc/setup2.sgml @@ -55,6 +55,74 @@ first starts. Most Cygwin applications do not make use of the </sect1> +<sect1 id="setup-maxmem"><title>Changing Cygwin's Maximum Memory</title> + +<para> +By default no Cygwin program can allocate more than 384 MB of memory +(program+data). You should not need to change this default in most +circumstances. However, if you need to use more real or virtual memory in +your machine you may add an entry in the either the +<literal>HKEY_LOCAL_MACHINE</literal> (to change the limit for all users) or +<literal>HKEY_CURRENT_USER</literal> (for just the current user) section of +the registry. +</para> + +<para> +Add the <literal>DWORD</literal> value <literal>heap_chunk_in_mb</literal> +and set it to the desired memory limit in decimal MB. It is preferred to do +this in Cygwin using the <command>regtool</command> program included in the +Cygwin package. +(For more information about <command>regtool</command> or the other Cygwin +utilities, see <Xref Linkend="using-utils"> or use each the +<literal>--help</literal> option of each util.) You should always be careful +when using <command>regtool</command> since damaging your system registry can +result in an unusable system. This example sets memory limit to 1024 MB: + +<screen> +regtool -i set /HKLM/Software/Cygnus\ Solutions/Cygwin/heap_chunk_in_mb 1024 +regtool -v list /HKLM/Software/Cygnus\ Solutions/Cygwin +</screen> +</para> + +<para> +Exit all running Cygwin processes and restart them. Memory can be allocated up +to the size of the system swap space minus any the size of any running +processes. The system swap should be at least as large as the physically +installed RAM and can be modified under the System category of the +Control Panel. +</para> + +<para> +Here is a small program written by DJ Delorie that tests the +memory allocation limit on your system: + +<screen> +main() +{ + unsigned int bit=0x40000000, sum=0; + char *x; + + while (bit > 4096) + { + x = malloc(bit); + if (x) + sum += bit; + bit >>= 1; + } + printf("%08x bytes (%.1fMb)\n", sum, sum/1024.0/1024.0); + return 0; +} +</screen> + +You can compile this program using: +<screen> +gcc max_memory.c -o max_memory.exe +</screen> + +Run the program and it will output the maximum amount of allocatable memory. +</para> +</sect1> + <sect1 id="setup-files"><title>Customizing bash</title> <para> |