* Ingo Molnar <mingo@xxxxxxx> wrote: > ------------------> > Subject: rt: fix ipi kfree(), introduce IPI_SOFTIRQ > From: Ingo Molnar <mingo@xxxxxxx> > Date: Thu Feb 12 09:06:11 CET 2009 > > in 2.6.28 generic_smp_call_function_interrupt() grew a kfree(), > which is a rather complex, sleepable method under -rt. But the > IPI code runs as a hardirq - which cannot run such code. > > So defer this work to a softirq context instead. It still stays > on the same CPU so the percpu IPI assumptions are upheld. On a second thought ... I think we could eliminate the kfree() instead, and keep the atomicity of IPI cross-calls. Linus expressed doubts about the IPI kmalloc()/kfree() pair we do in the generic SMP IPI code, suggesting that it probably does not help performance all that much - so such a change might be upstream-able as well and would keep -rt closer to mainline. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
