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authorIlya Dryomov <ilya.dryomov@inktank.com>2013-12-24 21:19:26 +0200
committerIlya Dryomov <ilya.dryomov@inktank.com>2013-12-31 20:32:22 +0200
commitf18650ace38ef200dd1578257c75e9407297953c (patch)
tree252f8675255569d1ab376b652cbb3c17332f36ca /include/linux/crush
parentbe3226acc5544bcc91e756eb3ee6ca7b74f6f0a8 (diff)
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crush: apply chooseleaf_tries to firstn mode too
Parameterize the attempts for the _firstn choose method, and apply the rule-specified tries count to firstn mode as well. Note that we have slightly different behavior here than with indep: If the firstn value is not specified for firstn, we pass through the normal attempt count. This maintains compatibility with legacy behavior. Note that this is usually *not* actually N^2 work, though, because of the descend_once tunable. However, descend_once is unfortunately *not* the same thing as 1 chooseleaf try because it is only checked on a reject but not on a collision. Sigh. In contrast, for indep, if tries is not specified we default to 1 recursive attempt, because that is simply more sane, and we have the option to do so. The descend_once tunable has no effect for indep. Reflects ceph.git commit 64aeded50d80942d66a5ec7b604ff2fcbf5d7b63. Signed-off-by: Ilya Dryomov <ilya.dryomov@inktank.com> Reviewed-by: Sage Weil <sage@inktank.com>
Diffstat (limited to 'include/linux/crush')
-rw-r--r--include/linux/crush/crush.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h
index 2e50bab91655..07b8fd4f81fc 100644
--- a/include/linux/crush/crush.h
+++ b/include/linux/crush/crush.h
@@ -165,7 +165,10 @@ struct crush_map {
__u32 choose_local_fallback_tries;
/* choose attempts before giving up */
__u32 choose_total_tries;
- /* attempt chooseleaf inner descent once; on failure retry outer descent */
+ /* attempt chooseleaf inner descent once for firstn mode; on
+ * reject retry outer descent. Note that this does *not*
+ * apply to a collision: in that case we will retry as we used
+ * to. */
__u32 chooseleaf_descend_once;
};