| Age | Commit message (Collapse) | Author | |
|---|---|---|---|
| 2007-12-23 | lib: proportion: fix underflow in prop_norm_percpu() | Peter Zijlstra | |
| Zhe Jiang noticed that its possible to underflow pl->events in prop_norm_percpu() when the value returned by percpu_counter_read() is less than the error on that read and the period delay > 1. In that case half might not trigger the batch increment and the value will be identical on the next iteration, causing the same half to be subtracted again and again. Fix this by rewriting the division as a single subtraction instead of a subtraction loop and using percpu_counter_sum() when the value returned by percpu_counter_read() is smaller than the error. The latter is still needed if we want pl->events to shrink properly in the error region. [akpm@linux-foundation.org: cleanups] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Jiang Zhe <zhe.jiang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | |||
| 2007-10-17 | lib: floating proportions | Peter Zijlstra | |
| Given a set of objects, floating proportions aims to efficiently give the proportional 'activity' of a single item as compared to the whole set. Where 'activity' is a measure of a temporal property of the items. It is efficient in that it need not inspect any other items of the set in order to provide the answer. It is not even needed to know how many other items there are. It has one parameter, and that is the period of 'time' over which the 'activity' is measured. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> | |||
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