Hello Ron! You wrote: > Malte [...] wrote: > > Does anyone have a clue why 2 GiB is the limit? > > http://www.puschitz.com/TuningLinuxForOracle.shtml#AddressMappingsOnLinux > 0GB-1GB User space - Used for executable and brk/sbrk allocations > (malloc uses brk for small chunks). > 1GB-2GB User space - Used for mmaps (shared memory), shared libraries > and malloc uses mmap (malloc uses mmap for large > chunks). > 2GB-3GB User space - Used for stack. > 3GB-4GB Kernel Space - Used for the kernel itself.
That was very helpful and explains a lot. I wonder whether a comprehensive documentation like this could be of use in some more official place, hmm. > > [...]Would using a swap partition > > instead of a swap file help? The 64G HIGHMEM kernel config option does not > > seem to make a difference. On a real AMD64 system, the program works fine > > with >2 GiB RAM, as was expected. Is there any way to make this work, > > besides changing the algorithm to use less than 2 GiB of memory? > > No. So true. I actually tried changing the PAGE_OFFSET and TASK_UNMAPPED_BASE divisor in an experimental kernel; this yielded no change for the application (the value is probably hardcoded in libc6' malloc and g++'s new implementation? Using the mmap system call directly might have worked, but having to recompile the base libs to make this work seemed a little extreme) > > PS: Please Cc: me if possible > > If you send question to the list, you should expect the answer > to only go to the list. Well, I know that answering to the list is necessary (otherwise other people might not profit from the solutions found) and I planned to reply to the list. Using Debian's web based archive and setting the right References: and In-Reply-To: headers is somewhat error-prone though (I hope I did not make any mistakes). A cc: makes it much easier to use the mailer's reply functions so threading is not broken. Also, the web archive is a pull medium, not a push medium, so not getting cc:ed is suboptimal. The other alternative is of course subscribing to the list, which I normally do, but bandwidth isn't necessarily free everywhere and debian-user is an extremely high-traffic list. (I'm on dozens of lists, including debian-devel, but debian-user is just madness unfortunately even with good MUAs). You might feel profiting from the answers given here while not subscribing is still unfair, but I actually can't see what enabling the web archive to be used instead hurts. I'm not going to reply to the reply-to thread since it's a tangential issue at best. Thanks for taking the time, -Malte -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
