lkml.org 
[lkml]   [2013]   [Apr]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 06/18] compat: backport ASYNC_DOMAIN_EXCLUSIVE()
On Wed, Apr 10, 2013 at 11:20 AM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On Wed, 2013-04-10 at 10:26 -0700, Luis R. Rodriguez wrote:
>
>> > I guess I'd have to review the async API,
>>
>> Yeap, reviewing the commit noted would help too.
>
> Yeah ... :)
>
>> > What's the use of just this when you don't have things like
>> > async_schedule_domain() and async_synchronize_full_domain(), regulator
>> > stuff wouldn't compile I think?
>>
>> You mean is not having the full asynch that deals with all registered
>> domains likely to have an issue on the useres of
>> async_synchronize_full_domain() ? Lets better ask Dan.
>
> I don't know. However it seems that in order to have an ASYNC_DOMAIN()
> or ASYNC_DOMAIN_EXCLUSIVE() you always need to *do* something with it,
> so for that you'd also need the functions async_schedule_domain() and
> async_synchronize_full_domain() or similar, at least, no?
>
> The point here seems to be making boot faster by starting a bunch of
> async probing inside a domain, and then you wait for the entire domain,
> so everything that's in that domain can be done in parallel.
>
> Say for example you have 20 SCSI drives. If you look at them serially
> then you'd waste much time waiting for the drives. The point here
> appears to be that you create a domain (using this macro), then add all
> the drives to the domain and then wait for the domain to finish.
>
> However, it seems entirely pointless to backport just a small part of
> the API?

Oh I agree don't get me wrong, however porting kernel/async.c seems
like a rather separate effort worth considering. As-is though I have
not seen any negative impact though to keep older subsystems from
compiling, ie its a no-op for older kernels as I see it.

Luis


\
 
 \ /
  Last update: 2013-04-10 22:01    [W:0.058 / U:0.548 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site