projects / people / pmueller / ipfire-2.x.git / blame
| Commit | Line | Data |
|---|---|---|
| 00e5a55c BS |
1 | From: Anton Blanchard <anton@samba.org> |
| 2 | Subject: mm: enable hashdist by default on 64bit NUMA | |
| 3 | References: bnc#501160 | |
| 4 | Patch-upstream: yes | |
| 5 | Git: c2fdf3a9b2d52842808a8e551b53b55dd9b45030 | |
| 6 | ||
| 7 | mm: enable hashdist by default on 64bit NUMA | |
| 8 | ||
| 9 | On PowerPC we allocate large boot time hashes on node 0. This leads to an | |
| 10 | imbalance in the free memory, for example on a 64GB box (4 x 16GB nodes): | |
| 11 | ||
| 12 | Free memory: | |
| 13 | Node 0: 97.03% | |
| 14 | Node 1: 98.54% | |
| 15 | Node 2: 98.42% | |
| 16 | Node 3: 98.53% | |
| 17 | ||
| 18 | If we switch to using vmalloc (like ia64 and x86-64) things are more | |
| 19 | balanced: | |
| 20 | ||
| 21 | Free memory: | |
| 22 | Node 0: 97.53% | |
| 23 | Node 1: 98.35% | |
| 24 | Node 2: 98.33% | |
| 25 | Node 3: 98.33% | |
| 26 | ||
| 27 | For many HPC applications we are limited by the free available memory on | |
| 28 | the smallest node, so even though the same amount of memory is used the | |
| 29 | better balancing helps. | |
| 30 | ||
| 31 | Since all 64bit NUMA capable architectures should have sufficient vmalloc | |
| 32 | space, it makes sense to enable it via CONFIG_64BIT. | |
| 33 | ||
| 34 | Signed-off-by: Anton Blanchard <anton@samba.org> | |
| 35 | Acked-by: David S. Miller <davem@davemloft.net> | |
| 36 | Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> | |
| 37 | Acked-by: Ralf Baechle <ralf@linux-mips.org> | |
| 38 | Cc: Heiko Carstens <heiko.carstens@de.ibm.com> | |
| 39 | Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> | |
| 40 | Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> | |
| 41 | Cc: Richard Henderson <rth@twiddle.net> | |
| 42 | Signed-off-by: Andrew Morton <akpm@linux-foundation.org> | |
| 43 | Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | |
| 44 | ||
| 45 | Acked-by: Nick Piggin <npiggin@suse.de> | |
| 46 | ||
| 47 | --- | |
| 48 | include/linux/bootmem.h | 6 +++--- | |
| 49 | 1 file changed, 3 insertions(+), 3 deletions(-) | |
| 50 | ||
| 51 | --- a/include/linux/bootmem.h | |
| 52 | +++ b/include/linux/bootmem.h | |
| 53 | @@ -144,10 +144,10 @@ extern void *alloc_large_system_hash(con | |
| 54 | ||
| 55 | #define HASH_EARLY 0x00000001 /* Allocating during early boot? */ | |
| 56 | ||
| 57 | -/* Only NUMA needs hash distribution. | |
| 58 | - * IA64 and x86_64 have sufficient vmalloc space. | |
| 59 | +/* Only NUMA needs hash distribution. 64bit NUMA architectures have | |
| 60 | + * sufficient vmalloc space. | |
| 61 | */ | |
| 62 | -#if defined(CONFIG_NUMA) && (defined(CONFIG_IA64) || defined(CONFIG_X86_64)) | |
| 63 | +#if defined(CONFIG_NUMA) && defined(CONFIG_64BIT) | |
| 64 | #define HASHDIST_DEFAULT 1 | |
| 65 | #else | |
| 66 | #define HASHDIST_DEFAULT 0 |