From: Ilya Dryomov Date: Wed, 19 Mar 2014 14:58:37 +0000 (+0200) Subject: crush: add chooseleaf_vary_r tunable X-Git-Tag: v3.15-rc1~61^2~42 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e2b149cc4ba00766aceb87950c6de72ea7fc8b2e;p=pandora-kernel.git crush: add chooseleaf_vary_r tunable The current crush_choose_firstn code will re-use the same 'r' value for the recursive call. That means that if we are hitting a collision or rejection for some reason (say, an OSD that is marked out) and need to retry, we will keep making the same (bad) choice in that recursive selection. Introduce a tunable that fixes that behavior by incorporating the parent 'r' value into the recursive starting point, so that a different path will be taken in subsequent placement attempts. Note that this was done from the get-go for the new crush_choose_indep algorithm. This was exposed by a user who was seeing PGs stuck in active+remapped after reweight-by-utilization because the up set mapped to a single OSD. Reflects ceph.git commit a8e6c9fbf88bad056dd05d3eb790e98a5e43451a. Signed-off-by: Ilya Dryomov Reviewed-by: Josh Durgin --- Reading git-diff-tree failed