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| author |   Alexander Gordeev <agordeev@redhat.com> | 2015-06-03 08:18:25 +0200 |
|---|---|---|
| committer |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-07-15 14:45:14 -0700 |
| commit | 679f9858b1769d740d933f5f1ad9dbe3292f26d2 (patch) | |
| tree | 0f1859a188d7ad2695aff72c005f9d38fbb7dd44 /kernel/rcu | |
| parent | rcu: Remove superfluous local variable in rcu_init_geometry() (diff) | |
| download | linux-dev-679f9858b1769d740d933f5f1ad9dbe3292f26d2.tar.xz linux-dev-679f9858b1769d740d933f5f1ad9dbe3292f26d2.zip | |
rcu: Cleanup rcu_init_geometry() code and arithmetics
This update simplifies rcu_init_geometry() code flow
and makes calculation of the total number of rcu_node
structures more easy to read.
The update relies on the fact num_rcu_lvl[] is never
accessed beyond rcu_num_lvls index by the rest of the
code. Therefore, there is no need initialize the whole
num_rcu_lvl[].
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>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 24 |
1 files changed, 10 insertions, 14 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index ad49dbed44fb..37ca8a867a1c 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -4082,7 +4082,6 @@ static void __init rcu_init_geometry(void) { ulong d; int i; - int j; int rcu_capacity[MAX_RCU_LVLS + 1]; /* @@ -4135,24 +4134,21 @@ static void __init rcu_init_geometry(void) if (nr_cpu_ids > rcu_capacity[MAX_RCU_LVLS]) panic("rcu_init_geometry: rcu_capacity[] is too small"); + /* Calculate the number of levels in the tree. */ + for (i = 1; nr_cpu_ids > rcu_capacity[i]; i++) { + } + rcu_num_lvls = i; + /* Calculate the number of rcu_nodes at each level of the tree. */ - for (i = 1; i <= MAX_RCU_LVLS; i++) - if (nr_cpu_ids <= rcu_capacity[i]) { - for (j = 0; j <= i; j++) { - int cap = rcu_capacity[i - j]; - num_rcu_lvl[j] = DIV_ROUND_UP(nr_cpu_ids, cap); - } - rcu_num_lvls = i; - for (j = i + 1; j <= MAX_RCU_LVLS; j++) - num_rcu_lvl[j] = 0; - break; - } + for (i = 0; i < rcu_num_lvls; i++) { + int cap = rcu_capacity[rcu_num_lvls - i]; + num_rcu_lvl[i] = DIV_ROUND_UP(nr_cpu_ids, cap); + } /* Calculate the total number of rcu_node structures. */ rcu_num_nodes = 0; - for (i = 0; i <= MAX_RCU_LVLS; i++) + for (i = 0; i < rcu_num_lvls; i++) rcu_num_nodes += num_rcu_lvl[i]; - rcu_num_nodes -= nr_cpu_ids; } /* |