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2012-06-09lib: Fix possible deadlock in flexible proportion codeJan Kara1-2/+8
When percpu counter function in fprop_new_period() is interrupted by an interrupt while holding counter lock, it can cause deadlock when the interrupt wants to take the lock as well. Fix the problem by disabling interrupts when calling percpu counter functions. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
2012-06-09lib: Proportions with flexible periodJan Kara1-0/+266
Implement code computing proportions of events of different type (like code in lib/proportions.c) but allowing periods to have different lengths. This allows us to have aging periods of fixed wallclock time which gives better proportion estimates given the hugely varying throughput of different devices - previous measuring of aging period by number of events has the problem that a reasonable period length for a system with low-end USB stick is not a reasonable period length for a system with high-end storage array resulting either in too slow proportion updates or too fluctuating proportion updates. Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>