Re: [PATCH v7 1/3] trace: Make removal of ring buffer pages atomic

[Vaibhav Nagarnaik]

On Tue, May 8, 2012 at 8:38 PM, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> BTW, why the two loops and not just:
>
>                for_each_buffer_cpu(buffer, cpu) {
>                        cpu_buffer = buffer->buffers[cpu];
>                        if (!cpu_buffer->nr_pages_to_update)
>                                continue;
>
>                        if (cpu_online(cpu))
>                                schedule_work_on(cpu, &cpu_buffer->update_pages_work);
>                        else
>                                rb_update_pages(cpu_buffer);
>                }
>
> ??
>
>
>>
>>               /* wait for all the updates to complete */
>>               for_each_buffer_cpu(buffer, cpu) {
>>                       cpu_buffer = buffer->buffers[cpu];
>> -                     if (cpu_buffer->nr_pages_to_update) {
>> -                             update_pages_handler(cpu_buffer);
>> -                     }
>> +                     if (!cpu_buffer->nr_pages_to_update||
>
>                              !cpu_buffer->nr_pages_to_update ||

This schedules work for all online CPUs and the offline CPUs resizing
(if any) can occur concurrently. It might not be too much of big deal
to just make it one loop.



Vaibhav Nagarnaik
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