diff --git a/winsup/doc/setup-net.sgml b/winsup/doc/setup-net.sgml index cc40f312b..547439249 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. DOCTOOL-INSERT-setup-env +DOCTOOL-INSERT-setup-maxmem DOCTOOL-INSERT-ntsec DOCTOOL-INSERT-setup-files diff --git a/winsup/doc/setup2.sgml b/winsup/doc/setup2.sgml index 4b2ecf6ef..592a25dc2 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 +Changing Cygwin's Maximum Memory + + +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 +HKEY_LOCAL_MACHINE (to change the limit for all users) or +HKEY_CURRENT_USER (for just the current user) section of +the registry. + + + +Add the DWORD value heap_chunk_in_mb +and set it to the desired memory limit in decimal MB. It is preferred to do +this in Cygwin using the regtool program included in the +Cygwin package. +(For more information about regtool or the other Cygwin +utilities, see or use each the +--help option of each util.) You should always be careful +when using regtool since damaging your system registry can +result in an unusable system. This example sets memory limit to 1024 MB: + + +regtool -i set /HKLM/Software/Cygnus\ Solutions/Cygwin/heap_chunk_in_mb 1024 +regtool -v list /HKLM/Software/Cygnus\ Solutions/Cygwin + + + + +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. + + + +Here is a small program written by DJ Delorie that tests the +memory allocation limit on your system: + + +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; +} + + +You can compile this program using: + +gcc max_memory.c -o max_memory.exe + + +Run the program and it will output the maximum amount of allocatable memory. + + + Customizing bash