diff options
author | Eric Dumazet <dada1@cosmosbay.com> | 2005-11-05 16:25:54 (GMT) |
---|---|---|
committer | Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-15 03:55:15 (GMT) |
commit | 529a340402e419f935d411ce0a085e96fcaf3872 (patch) | |
tree | d5941a16060f3c64912e6cb393d6eaa8f4704652 /arch/x86_64 | |
parent | e4e5d324b9c5586f408a72d1534474c449dd5212 (diff) | |
download | linux-fsl-qoriq-529a340402e419f935d411ce0a085e96fcaf3872.tar.xz |
[PATCH] x86_64: Optimize NUMA node hash function
Compute the highest possible value for memnode_shift, in order to reduce
footprint of memnodemap[] to the minimum, thus making all users
(phys_to_nid(), kfree()), more cache friendly.
Before the patch :
Node 0 MemBase 0000000000000000 Limit 00000001ffffffff
Node 1 MemBase 0000000200000000 Limit 00000003ffffffff
Using 23 for the hash shift. Max adder is 3ffffffff
After the patch :
Node 0 MemBase 0000000000000000 Limit 00000001ffffffff
Node 1 MemBase 0000000200000000 Limit 00000003ffffffff
Using 33 for the hash shift.
In this case, only 2 bytes of memnodemap[] are used, instead of 2048
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64')
-rw-r--r-- | arch/x86_64/mm/numa.c | 67 |
1 files changed, 43 insertions, 24 deletions
diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c index 4bf6458..edd5559 100644 --- a/arch/x86_64/mm/numa.c +++ b/arch/x86_64/mm/numa.c @@ -38,38 +38,57 @@ cpumask_t node_to_cpumask[MAX_NUMNODES] __read_mostly; int numa_off __initdata; -int __init compute_hash_shift(struct node *nodes, int numnodes) + +/* + * Given a shift value, try to populate memnodemap[] + * Returns : + * 1 if OK + * 0 if memnodmap[] too small (of shift too small) + * -1 if node overlap or lost ram (shift too big) + */ +static int __init populate_memnodemap( + const struct node *nodes, int numnodes, int shift) { int i; - int shift = 20; - unsigned long addr,maxend=0; - - for (i = 0; i < numnodes; i++) - if ((nodes[i].start != nodes[i].end) && (nodes[i].end > maxend)) - maxend = nodes[i].end; + int res = -1; + unsigned long addr, end; - while ((1UL << shift) < (maxend / NODEMAPSIZE)) - shift++; - - printk (KERN_DEBUG"Using %d for the hash shift. Max adder is %lx \n", - shift,maxend); - memset(memnodemap,0xff,sizeof(*memnodemap) * NODEMAPSIZE); + memset(memnodemap, 0xff, sizeof(memnodemap)); for (i = 0; i < numnodes; i++) { - if (nodes[i].start == nodes[i].end) + addr = nodes[i].start; + end = nodes[i].end; + if (addr >= end) continue; - for (addr = nodes[i].start; - addr < nodes[i].end; - addr += (1UL << shift)) { - if (memnodemap[addr >> shift] != 0xff) { - printk(KERN_INFO - "Your memory is not aligned you need to rebuild your kernel " - "with a bigger NODEMAPSIZE shift=%d adder=%lu\n", - shift,addr); + if ((end >> shift) >= NODEMAPSIZE) + return 0; + do { + if (memnodemap[addr >> shift] != 0xff) return -1; - } memnodemap[addr >> shift] = i; - } + addr += (1 << shift); + } while (addr < end); + res = 1; } + return res; +} + +int __init compute_hash_shift(struct node *nodes, int numnodes) +{ + int shift = 20; + + while (populate_memnodemap(nodes, numnodes, shift + 1) >= 0) + shift++; + + printk(KERN_DEBUG "Using %d for the hash shift.\n", + shift); + + if (populate_memnodemap(nodes, numnodes, shift) != 1) { + printk(KERN_INFO + "Your memory is not aligned you need to rebuild your kernel " + "with a bigger NODEMAPSIZE shift=%d\n", + shift); + return -1; + } return shift; } |