diff options
author | Paul Mackerras <paulus@samba.org> | 2006-02-08 09:43:08 +1100 |
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committer | Paul Mackerras <paulus@samba.org> | 2006-02-08 09:43:08 +1100 |
commit | 8f75015f33c3005e0bbf83ffc0d5e0b4262cc03d (patch) | |
tree | a3c34ad86ccdc904bb43af6cd1cb163231c29276 /include/linux/mmzone.h | |
parent | 076d022c566fddde41fd4a858dd24bacad8304d7 (diff) | |
parent | e060e084e7d9e1c62d02cb6b8d3fe07db5317eaa (diff) |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc
Diffstat (limited to 'include/linux/mmzone.h')
-rw-r--r-- | include/linux/mmzone.h | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 93a849f742d..ebfc238cc24 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -91,10 +91,21 @@ struct per_cpu_pageset { * be 8 (2 ** 3) zonelists. GFP_ZONETYPES defines the number of possible * combinations of zone modifiers in "zone modifier space". * + * As an optimisation any zone modifier bits which are only valid when + * no other zone modifier bits are set (loners) should be placed in + * the highest order bits of this field. This allows us to reduce the + * extent of the zonelists thus saving space. For example in the case + * of three zone modifier bits, we could require up to eight zonelists. + * If the left most zone modifier is a "loner" then the highest valid + * zonelist would be four allowing us to allocate only five zonelists. + * Use the first form for GFP_ZONETYPES when the left most bit is not + * a "loner", otherwise use the second. + * * NOTE! Make sure this matches the zones in <linux/gfp.h> */ #define GFP_ZONEMASK 0x07 -#define GFP_ZONETYPES 5 +/* #define GFP_ZONETYPES (GFP_ZONEMASK + 1) */ /* Non-loner */ +#define GFP_ZONETYPES ((GFP_ZONEMASK + 1) / 2 + 1) /* Loner */ /* * On machines where it is needed (eg PCs) we divide physical memory |