From 5ad867775f36f3111dbfdb18414f7ccdf3e843ea Mon Sep 17 00:00:00 2001
From: Iustin Pop <iustin@google.com>
Date: Thu, 14 Jan 2010 17:05:29 +0100
Subject: [PATCH] Split the balancing function in two parts
Currently in the balancing function we do two thing:
- take the decision where to do a new balancing round or not
- and actually computing the balancing round
This is not nice, as the two parts are conceptually separate, so this
patch splits the decision on whether to descend or not to a new
function.
---
Ganeti/HTools/Cluster.hs | 39 +++++++++++++++++++++------------------
hbal.hs | 5 ++++-
2 files changed, 25 insertions(+), 19 deletions(-)
diff --git a/Ganeti/HTools/Cluster.hs b/Ganeti/HTools/Cluster.hs
index e29eb0981..ab5cbb4b5 100644
--- a/Ganeti/HTools/Cluster.hs
+++ b/Ganeti/HTools/Cluster.hs
@@ -47,6 +47,7 @@ module Ganeti.HTools.Cluster
, printInsts
-- * Balacing functions
, checkMove
+ , doNextBalance
, tryBalance
, compCV
, printStats
@@ -77,7 +78,6 @@ type AllocSolution = ([FailMode], Int, Maybe (Score, AllocElement))
-- | Allocation\/relocation element.
type AllocElement = (Node.List, Instance.Instance, [Node.Node])
-
-- | The complete state for the balancing solution
data Table = Table Node.List Instance.List Score [Placement]
deriving (Show)
@@ -448,29 +448,32 @@ checkMove nodes_idx disk_moves ini_tbl victims =
else
best_tbl
+-- | Check if we are allowed to go deeper in the balancing
+
+doNextBalance :: Table -- ^ The starting table
+ -> Int -- ^ Remaining length
+ -> Score -- ^ Score at which to stop
+ -> Bool -- ^ The resulting table and commands
+doNextBalance ini_tbl max_rounds min_score =
+ let Table _ _ ini_cv ini_plc = ini_tbl
+ ini_plc_len = length ini_plc
+ in (max_rounds < 0 || ini_plc_len < max_rounds) && ini_cv > min_score
+
-- | Run a balance move
tryBalance :: Table -- ^ The starting table
- -> Int -- ^ Remaining length
-> Bool -- ^ Allow disk moves
- -> Score -- ^ Score at which to stop
-> Maybe Table -- ^ The resulting table and commands
-tryBalance ini_tbl max_rounds disk_moves min_score =
- let Table ini_nl ini_il ini_cv ini_plc = ini_tbl
- ini_plc_len = length ini_plc
- allowed_next = (max_rounds < 0 || ini_plc_len < max_rounds) &&
- ini_cv > min_score
+tryBalance ini_tbl disk_moves =
+ let Table ini_nl ini_il ini_cv _ = ini_tbl
+ all_inst = Container.elems ini_il
+ node_idx = map Node.idx . filter (not . Node.offline) $
+ Container.elems ini_nl
+ fin_tbl = checkMove node_idx disk_moves ini_tbl all_inst
+ (Table _ _ fin_cv _) = fin_tbl
in
- if allowed_next
- then let all_inst = Container.elems ini_il
- node_idx = map Node.idx . filter (not . Node.offline) $
- Container.elems ini_nl
- fin_tbl = checkMove node_idx disk_moves ini_tbl all_inst
- (Table _ _ fin_cv _) = fin_tbl
- in
- if fin_cv < ini_cv
- then Just fin_tbl -- this round made success, try deeper
- else Nothing
+ if fin_cv < ini_cv
+ then Just fin_tbl -- this round made success, return the new table
else Nothing
-- * Allocation functions
diff --git a/hbal.hs b/hbal.hs
index ae4cb80c9..66681adc4 100644
--- a/hbal.hs
+++ b/hbal.hs
@@ -94,7 +94,10 @@ iterateDepth :: Cluster.Table -- ^ The starting table
iterateDepth ini_tbl max_rounds disk_moves nmlen imlen
cmd_strs oneline min_score =
let Cluster.Table ini_nl ini_il _ _ = ini_tbl
- m_fin_tbl = Cluster.tryBalance ini_tbl max_rounds disk_moves min_score
+ allowed_next = Cluster.doNextBalance ini_tbl max_rounds min_score
+ m_fin_tbl = if allowed_next
+ then Cluster.tryBalance ini_tbl disk_moves
+ else Nothing
in
case m_fin_tbl of
Just fin_tbl ->
--
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