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rcu: Limit rcu_capacity[] size to RCU_NUM_LVLS items
Number of items in rcu_capacity[] array is defined by macro MAX_RCU_LVLS. However, that array is never accessed beyond RCU_NUM_LVLS index. Therefore, we can limit the array to RCU_NUM_LVLS items and eliminate MAX_RCU_LVLS. As result, in most cases the memory is conserved. Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Alexander Gordeev <agordeev@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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2 changed files with 6 additions and 8 deletions
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@ -3998,19 +3998,19 @@ static void __init rcu_init_one(struct rcu_state *rsp,
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"rcu_node_0",
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"rcu_node_1",
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"rcu_node_2",
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"rcu_node_3" }; /* Match MAX_RCU_LVLS */
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"rcu_node_3" };
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static const char * const fqs[] = {
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"rcu_node_fqs_0",
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"rcu_node_fqs_1",
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"rcu_node_fqs_2",
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"rcu_node_fqs_3" }; /* Match MAX_RCU_LVLS */
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"rcu_node_fqs_3" };
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static u8 fl_mask = 0x1;
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int cpustride = 1;
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int i;
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int j;
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struct rcu_node *rnp;
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BUILD_BUG_ON(MAX_RCU_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */
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BUILD_BUG_ON(RCU_NUM_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */
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/* Silence gcc 4.8 false positive about array index out of range. */
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if (rcu_num_lvls <= 0 || rcu_num_lvls > RCU_NUM_LVLS)
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@ -4082,7 +4082,7 @@ static void __init rcu_init_geometry(void)
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{
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ulong d;
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int i;
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int rcu_capacity[MAX_RCU_LVLS];
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int rcu_capacity[RCU_NUM_LVLS];
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/*
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* Initialize any unspecified boot parameters.
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@ -4122,14 +4122,14 @@ static void __init rcu_init_geometry(void)
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* with the given number of levels.
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*/
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rcu_capacity[0] = rcu_fanout_leaf;
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for (i = 1; i < MAX_RCU_LVLS; i++)
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for (i = 1; i < RCU_NUM_LVLS; i++)
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rcu_capacity[i] = rcu_capacity[i - 1] * RCU_FANOUT;
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/*
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* The tree must be able to accommodate the configured number of CPUs.
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* If this limit is exceeded than we have a serious problem elsewhere.
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*/
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if (nr_cpu_ids > rcu_capacity[MAX_RCU_LVLS - 1])
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if (nr_cpu_ids > rcu_capacity[RCU_NUM_LVLS - 1])
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panic("rcu_init_geometry: rcu_capacity[] is too small");
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/* Calculate the number of levels in the tree. */
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@ -36,8 +36,6 @@
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* Of course, your mileage may vary.
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*/
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#define MAX_RCU_LVLS 4
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#ifdef CONFIG_RCU_FANOUT
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#define RCU_FANOUT CONFIG_RCU_FANOUT
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#else /* #ifdef CONFIG_RCU_FANOUT */
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