Messages in this thread | | | Date | Mon, 29 Jan 2007 10:38:45 -0800 (PST) | From | David Rientjes <> | Subject | Re: [patch -mm 3/5] x86_64: fixed-size remaining fake nodes |
| |
On Mon, 29 Jan 2007, Andi Kleen wrote:
> On Thursday 25 January 2007 22:37, David Rientjes wrote: > > Any leftover memory is allocated > > to a final node unless the command-line ends with a comma. > > That sounds like syntactical vinegar and a nasty trap. Remember > that venus probe that got lost because of a wrong comma. > Can you find some nicer syntax for that please? >
The only other appropriate syntax that comes to mind is perhaps a command-line that ends with a 0. For example, numa=fake=2*512,0 would allocate two 512M nodes and nothing for the remaining RAM.
> Also it's pretty complex. Are there use cases for all of this? >
There are. Configurable node sizes (i.e. 'numa=fake=512,4*128', etc) are the major concept and help to avoid the overhead associated with something like 64 nodes of 64M each on a 4G machine. We've seen some inefficiencies with scanning through so many zone lists on page_alloc when we encounter a full node. Additional support such as 'numa=fake=2*512,*128' are used more for machines where you're unsure of their total system RAM in the first place but want to make sure you have the node sizes you need.
David - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |