From f18650ace38ef200dd1578257c75e9407297953c Mon Sep 17 00:00:00 2001 From: Ilya Dryomov Date: Tue, 24 Dec 2013 21:19:26 +0200 Subject: 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 Reviewed-by: Sage Weil --- include/linux/crush/crush.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include/linux/crush') diff --git a/include/linux/crush/crush.h b/include/linux/crush/crush.h index 2e50bab..07b8fd4 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; }; -- cgit v1.1