Re: poll: allow f_op->poll to sleep, take #3

From: Tejun Heo
Date: Sun Nov 23 2008 - 23:30:20 EST


Ingo Molnar wrote:
>> And @sync might be useful depending on who's waking it up, so we
>> either need to change the wake interface or give it an easier way to
>> pass those parameters as received. The callback function isn't the
>> right place to ignore those parameters. It simply doesn't know why
>> the caller is passing them in or what they mean under the
>> circumstances.
>
> We'll likely eliminate the 'sync' parameter from the scheduler. It's
> not a flag that should be proliferated.

But it's still being used in quite hot paths (pipe, splice, socket)
and I don't really wanna mix up a change which can cause subtle
scheduling related performance regression into this patch. How about
using the dummy waitqueue hack for now and when removing the @sync
param, switch it to one of wakeup APIs? I'll be happy to add big /*
TODO */ comment in the function.

Thanks.

--
tejun
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