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SubjectRe: + sched-use-tasklet-to-call-balancing.patch added to -mm tree
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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