Re: Realloc is blocking execution
On Wed, 14 Oct 2009, George Danchev wrote:
Hm, I guess that the library functions are just fine and it has something to do
with the kernel performing memory overcommitment by default. You can prevent
that by (from the tail of realloc(3) man page):
echo 2 > /proc/sys/vm/overcommit_memory
and see if that makes any difference.
Rf. see overcommit_memory in $linux_source/Documentation/sysctl/vm.txt
Don't forget to look at the "vm.overcommit_ratio" sysctl. Perhaps I'm
misunderstanding it, but on my workstation with 4G physical RAM and no
swap, I set it to 99, leading to
total virtual address space on the system
<= swapspace + physmem * (overcommit_ratio / 100)
= 0 + 4096M * 99%
I think 4096M * 1% ~= 41M should be enough for the "hard" needs of the
kernel, and all other address space (backed by physical RAM) should be
available to processes.
That, or I don't get it at all.
Cheers,
lacos
[0] http://linux-mm.org/OverCommitAccounting
[1] http://www.linuxinsight.com/proc_sys_vm_overcommit_ratio.html
[2] http://linux.die.net/man/5/proc
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