On 04/05/11 01:31, Otto Moerbeek wrote:
On Tue, Apr 05, 2011 at 12:57:28AM -0400, STeve Andre' wrote:
On 04/05/11 00:52, Otto Moerbeek wrote:
On Mon, Apr 04, 2011 at 09:23:48PM -0400, STeve Andre' wrote:
On 04/04/11 19:59, Miod Vallat wrote:
So, now that BIGMEM is up, what is the new max? are we talking TB?
or is 8GB the new upper limit?
The limit of the number of vague questions for which there is only vague
answers is infinite.
Which limit are you talking about? The limit of the number of open files
in the kernel? The limit of the number of distinct PCI busses in the
kernel? The limit of the number of distinct keys handled at the keyboard
driver level? The limit of profanity comments in the kernel source code?
Miod
I think the (first) question is how much memory can be addressed?
--STeve Andre'
As vague as the first question. Addressing memory is done from a context.
-Otto
Hmm. OK -- can amd64 then handle 256G of memory?
Still missing context. There's the kernel and userland, physical and
virtual memory to name a few things that tell a bit about context.
MAXDSIZE is the maximum of virtual memory a process can allocate using
malloc and similar mechanisms.
MAXDSIZE has already been at 8GB for a while. That didn't change with
bigmem, which talks about addressable physical memory from the kernel.
The two limits have no immediate connection. So the answer is: no,
enabling bigmem did not change MAXDSIZE. Processes cannot allocate
more virtual memory from the heap with bigmem enabled.
Of course now that the kernel can address more physical memory, it
might consider backing more of the allocated virtual memory with
physical pages at any point in time.
-Otto
All right, let me ask again, or a little differently. I understand
what you are saying, but the 32 bit limit on amd64 has surprised
a lot of people lately (I know, they didn't read up).
How much physical memory can I stuff into an amd64 box now?
Could I have a 64G machine and run ten 6G processes without
swapping?
--STeve Andre'
