Ilya Dryomov 958a27658d crush: straw2 bucket type with an efficient 64-bit crush_ln() ... This is an improved straw bucket that correctly avoids any data movement between items A and B when neither A nor B's weights are changed. Said differently, if we adjust the weight of item C (including adding it anew or removing it completely), we will only see inputs move to or from C, never between other items in the bucket. Notably, there is not intermediate scaling factor that needs to be calculated. The mapping function is a simple function of the item weights. The below commits were squashed together into this one (mostly to avoid adding and then yanking a ~6000 lines worth of crush_ln_table): - crush: add a straw2 bucket type - crush: add crush_ln to calculate nature log efficently - crush: improve straw2 adjustment slightly - crush: change crush_ln to provide 32 more digits - crush: fix crush_get_bucket_item_weight and bucket destroy for straw2 - crush/mapper: fix divide-by-0 in straw2 (with div64_s64() for draw = ln / w and INT64_MIN -> S64_MIN - need to create a proper compat.h in ceph.git) Reflects ceph.git commits 242293c908e923d474910f2b8203fa3b41eb5a53, 32a1ead92efcd351822d22a5fc37d159c65c1338, 6289912418c4a3597a11778bcf29ed5415117ad9, 35fcb04e2945717cf5cfe150b9fa89cb3d2303a1, 6445d9ee7290938de1e4ee9563912a6ab6d8ee5f, b5921d55d16796e12d66ad2c4add7305f9ce2353. Signed-off-by: Ilya Dryomov <idryomov@gmail.com>		2015-04-22 18:33:43 +03:00
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crush.h	crush: straw2 bucket type with an efficient 64-bit crush_ln()	2015-04-22 18:33:43 +03:00
hash.h
mapper.h	crush: eliminate CRUSH_MAX_SET result size limitation	2013-12-31 20:32:14 +02:00