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authorPaul Jackson <pj@sgi.com>2006-01-08 01:01:46 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:13:42 -0800
commit96b7f34143c2c823a6a750fcb758fc66c44945d2 (patch)
treea17cadb13e4eeb555f32186579d5d174cf51796b /mm
parent10cef6029502915bdb3cf0821d425cf9dc30c817 (diff)
[PATCH] cpuset: better bitmap remap defaults
Fix the default behaviour for the remap operators in bitmap, cpumask and nodemask. As previously submitted, the pair of masks <A, B> defined a map of the positions of the set bits in A to the corresponding bits in B. This is still true. The issue is how to map the other positions, corresponding to the unset (0) bits in A. As previously submitted, they were all mapped to the first set bit position in B, a constant map. When I tried to code per-vma mempolicy rebinding using these remap operators, I realized this was wrong. This patch changes the default to map all the unset bit positions in A to the same positions in B, the identity map. For example, if A has bits 4-7 set, and B has bits 9-12 set, then the map defined by the pair <A, B> maps each bit position in the first 32 bits as follows: 0 ==> 0 ... 3 ==> 3 4 ==> 9 ... 7 ==> 12 8 ==> 8 9 ==> 9 ... 31 ==> 31 This now corresponds to the typical behaviour desired when migrating pages and policies from one cpuset to another. The pages on nodes within the original cpuset, and the references in memory policies to nodes within the original cpuset, are migrated to the corresponding cpuset-relative nodes in the destination cpuset. Other pages and node references are left untouched. Signed-off-by: Paul Jackson <pj@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
0 files changed, 0 insertions, 0 deletions