Messages in this thread |  | | | Date | Tue, 7 Nov 2006 10:18:44 -0800 (PST) | | From | Christoph Lameter <> | | Subject | Re: + sched-use-tasklet-to-call-balancing.patch added to -mm tree |
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On Tue, 7 Nov 2006, Siddha, Suresh B wrote:
> tasklet_schedule doesn't schedule if there is already one scheduled.
Right.
/* Tasklets --- multithreaded analogue of BHs. Main feature differing them of generic softirqs: tasklet is running only on one CPU simultaneously.
Main feature differing them of BHs: different tasklets may be run simultaneously on different CPUs.
Properties: * If tasklet_schedule() is called, then tasklet is guaranteed to be executed on some cpu at least once after this.
^^^^ Crap. Not equivalent. Must be guaranteed to run on the same cpu. * If the tasklet is already scheduled, but its excecution is still not started, it will be executed only once. * If this tasklet is already running on another CPU (or schedule is called from tasklet itself), it is rescheduled for later. * Tasklet is strictly serialized wrt itself, but not wrt another tasklets. If client needs some intertask synchronization, he makes it with spinlocks. */
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