On Thursday 13 May 2010, Shlomi Fish wrote: > Then it is very likely that the memory allocated to the "mem" pointer will > not > be returned to the kernel due to the nature of malloc() and how it is an > abstraction above sbrk(): > > http://linux.die.net/man/2/sbrk > > perl 5 makes use of sbrk eventually as well (either by using the libc > malloc() > or by implementing its own). Note that for very large allocations, perl may > use mmap() instead of sbrk() in which case the memory may get released. I've > seen it in a demonstration program that someone pasted on IRC, a few years > back.
Yes, I think the memory space allocated by a process using malloc() can't be really freed up until the calling process is terminated. And processes that uses mmap() can unmap those chunk size of memory when it's not needed. I guess Perl by default allocates memory using malloc() and changes the memory allocated using sbrk(). So how does Perl know it has to mmap() instead if the (huge) size was being used incrementally (not at once)? I now believe the only way to free up the space used by a small portion of your program is forking that part of the program so that it will run as a child process and return all the memory used by it back to the system. Please correct me if I am wrong. -- Regards, Akhthar Parvez K http://Tips.SysAdminGUIDE.COM UNIX is basically a simple operating system, but you have to be a genius to understand the simplicity - Dennie Richie -- To unsubscribe, e-mail: beginners-unsubscr...@perl.org For additional commands, e-mail: beginners-h...@perl.org http://learn.perl.org/
