Messages in this thread Patch in this message | | | From | Pan Xinhui <> | Subject | [PATCH v2] locking/qspinlock: Use __this_cpu_dec instead | Date | Tue, 14 Jun 2016 14:37:27 +0800 |
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queued_spin_lock_slowpath should not worry about another queued_spin_lock_slowpath which runs in interrupt changes node->count by accident because node->count keeps the same value everytime we enter/leave queued_spin_lock_slowpath.
On some archs this_cpu_dec will save/restore irq flags, this will give a heavy work load. Lets use __this_cpu_dec instead.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> --- change from v1: replace this_cpu_ptr with __this_cpu_dec --- kernel/locking/qspinlock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 99f31e4..9fd1a1e 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -492,7 +492,7 @@ release: /* * release the node */ - this_cpu_dec(mcs_nodes[0].count); + __this_cpu_dec(mcs_nodes[0].count); } EXPORT_SYMBOL(queued_spin_lock_slowpath); -- 1.9.1
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