On Sat, 2007-12-08 at 04:07 +0530, Balbir Singh wrote: > Here's a dumb simple implementation of fake NUMA nodes for PowerPC. Fake > NUMA nodes can be specified using the following command line option >
>
> Comments are as always welcome!
Here's some :)
> diff -puN arch/powerpc/mm/numa.c~ppc-fake-numa-easy arch/powerpc/mm/numa.c
> --- linux-2.6.24-rc4-mm1/arch/powerpc/mm/numa.c~ppc-fake-numa-easy
> 2007-12-07 21:25:55.000000000 +0530
> +++ linux-2.6.24-rc4-mm1-balbir/arch/powerpc/mm/numa.c 2007-12-08
> 03:19:46.000000000 +0530
> @@ -24,6 +24,8 @@
>
> static int numa_enabled = 1;
>
> +static char *cmdline __initdata;
Can you call this fake_numa_args or something, cmdline is a bit generic.
> @@ -39,6 +41,43 @@ static bootmem_data_t __initdata plat_no
> static int min_common_depth;
> static int n_mem_addr_cells, n_mem_size_cells;
>
> +static int __cpuinit fake_numa_create_new_node(unsigned long end_pfn,
> + unsigned int *nid)
> +{
> + unsigned long long mem;
> + char *p = cmdline;
> + static unsigned int fake_nid = 0;
> + static unsigned long long curr_boundary = 0;
> +
> + *nid = fake_nid;
As I mentioned in my other email I think this is broken, you
unconditionally overwrite *nid, even if no fake numa was specified?
> + if (!p)
> + return 0;
> +
> + mem = memparse(p, &p);
> + if (!mem)
> + return 0;
> +
> + if (mem < curr_boundary)
> + return 0;
> +
> + curr_boundary = mem;
> +
> + if ((end_pfn << PAGE_SHIFT) > mem) {
> + /*
> + * Skip commas and spaces
> + */
> + while (*p == ',' || *p == ' ' || *p == '\t')
> + p++;
> +
> + cmdline = p;
> + fake_nid++;
> + *nid = fake_nid;
> + dbg("created new fake_node with id %d\n", fake_nid);
> + return 1;
> + }
> + return 0;
> +}
> +
> static void __cpuinit map_cpu_to_node(int cpu, int node)
> {
> numa_cpu_lookup_table[cpu] = node;
> @@ -344,12 +383,14 @@ static void __init parse_drconf_memory(s
> if (nid == 0xffff || nid >= MAX_NUMNODES)
> nid = default_nid;
> }
> - node_set_online(nid);
>
> size = numa_enforce_memory_limit(start, lmb_size);
> if (!size)
> continue;
>
> + fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
> + node_set_online(nid);
I can't convince myself that this is 100% ok, the moving of
node_set_online(). At the very least it's a change in behaviour,
previously we would online the node regardless of the memory limit.
> add_active_range(nid, start >> PAGE_SHIFT,
> (start >> PAGE_SHIFT) + (size >> PAGE_SHIFT));
> }
> @@ -429,7 +470,6 @@ new_range:
> nid = of_node_to_nid_single(memory);
> if (nid < 0)
> nid = default_nid;
> - node_set_online(nid);
>
> if (!(size = numa_enforce_memory_limit(start, size))) {
> if (--ranges)
> @@ -438,6 +478,9 @@ new_range:
> continue;
> }
>
> + fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
> + node_set_online(nid);
Ditto previous comment.
cheers
--
Michael Ellerman
OzLabs, IBM Australia Development Lab
wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)
We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person
signature.asc
Description: This is a digitally signed message part
_______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@ozlabs.org https://ozlabs.org/mailman/listinfo/linuxppc-dev
