Commit Graph

6 Commits

Author SHA1 Message Date
Sage Weil
50b885b96c ceph: whitespace cleanup
Signed-off-by: Sage Weil <sage@newdream.net>
2009-12-03 14:59:44 -08:00
Sage Weil
fb690390e3 ceph: make CRUSH hash function a bucket property
Make the integer hash function a property of the bucket it is used on.  This
allows us to gracefully add support for new hash functions without starting
from scatch.

Signed-off-by: Sage Weil <sage@newdream.net>
2009-11-07 20:18:22 -08:00
Sage Weil
c6cf726316 ceph: make CRUSH hash functions non-inline
These are way to big to be inline.  I missed crush/* when doing the inline
audit for akpm's review.

Signed-off-by: Sage Weil <sage@newdream.net>
2009-11-06 16:39:26 -08:00
Sage Weil
33aa96e743 crush: always return a value from crush_bucket_choose
Even when we encounter a corrupt bucket.  We still BUG().  This fixes
the warning

fs/ceph/crush/mapper.c: In function 'crush_choose':
fs/ceph/crush/mapper.c:352: warning: control may reach end of non-void function
'crush_bucket_choose' being inlined

Signed-off-by: Sage Weil <sage@newdream.net>
2009-11-01 17:53:24 -08:00
Sage Weil
b28813a61d ceph: gracefully avoid empty crush buckets
This avoids a divide by zero when the input and/or map are
malformed.

Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-07 10:59:34 -07:00
Sage Weil
5ecc0a0f81 ceph: CRUSH mapping algorithm
CRUSH is a pseudorandom data distribution function designed to map
inputs onto a dynamic hierarchy of devices, while minimizing the
extent to which inputs are remapped when the devices are added or
removed.  It includes some features that are specifically useful for
storage, most notably the ability to map each input onto a set of N
devices that are separated across administrator-defined failure
domains.  CRUSH is used to distribute data across the cluster of Ceph
storage nodes.

More information about CRUSH can be found in this paper:

    http://www.ssrc.ucsc.edu/Papers/weil-sc06.pdf

Signed-off-by: Sage Weil <sage@newdream.net>
2009-10-06 11:31:11 -07:00