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| author | Anton Blanchard <anton@samba.org> | 2009-09-21 19:56:43 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2009-09-24 15:31:46 +1000 |
| commit | ea55bf29126f0066a4e82a8545437494ff4fc431 (patch) | |
| tree | 53259bbb7c3984f53fd0026fd5867a1322b36685 /arch/powerpc | |
| parent | f2053f1a7bf6005b4e81826b1ac8d0b4117c4cf0 (diff) | |
| download | op-kernel-dev-ea55bf29126f0066a4e82a8545437494ff4fc431.zip op-kernel-dev-ea55bf29126f0066a4e82a8545437494ff4fc431.tar.gz | |
powerpc: Increase NODES_SHIFT on 64bit from 4 to 8
Some System p configurations can already have more than 16 nodes so we
need to increase NODES_SHIFT. I chose 256 to give us some room to grow in the
future, although we can look at something smaller if the memory bloat is
considered too much.
Unless we clamp MAX_ACTIVE_REGIONS we end up with 300kB of extra bloat in
early_node_map in mm/page_alloc.c:
< 6144 early_node_map
> 307200 early_node_map
due to:
#if MAX_NUMNODES >= 32
/* If there can be many nodes, allow up to 50 holes per node */
#define MAX_ACTIVE_REGIONS (MAX_NUMNODES*50)
#else
/* By default, allow up to 256 distinct regions */
#define MAX_ACTIVE_REGIONS 256
Since our memory is mostly contiguous it seems reasonable to keep this
at 256 for now. I also set 32bit to 32 to save space (is there any chance
a 32bit system will have more than 32 discontiguous memory ranges?).
Even with that fixed we have a few data structures that grow:
< 896 bootmem_node_data
> 14336 bootmem_node_data
< 1280 node_devices
> 20480 node_devices
< 25088 kmalloc_caches
> 59648 kmalloc_caches
< 1632 hstates
> 21792 hstates
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/Kconfig | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 4fd4790..10a0a54 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -385,9 +385,15 @@ config NUMA config NODES_SHIFT int + default "8" if PPC64 default "4" depends on NEED_MULTIPLE_NODES +config MAX_ACTIVE_REGIONS + int + default "256" if PPC64 + default "32" + config ARCH_SELECT_MEMORY_MODEL def_bool y depends on PPC64 |
