linux-kernel - Re: [PATCH 1/2] RT: Preemptible Function-Call-IPI Support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20070731142235.GB22209@elte.hu>
Date:	Tue, 31 Jul 2007 16:22:35 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Gregory Haskins <ghaskins@...ell.com>
Cc:	linux-kernel@...r.kernel.org, linux-rt-users@...r.kernel.org
Subject: Re: [PATCH 1/2] RT: Preemptible Function-Call-IPI Support


* Gregory Haskins <ghaskins@...ell.com> wrote:

> > as far as the prioritization of function calls goes, _that_ makes 
> > sense, but it should not be a separate API but should be done to our 
> > normal workqueue APIs. That not only extends the effects of 
> > priorities to all current workqueue using kernel subsystems, but 
> > also keeps the API more unified. We really dont want to have too 
> > many -rt specific APIs.
> 
> I agree with you that having some kind of priority and cpu-binding 
> specifiers for work-queues would be very cool indeed.  However, note 
> that I didn't actually introduce a new API(*), per se.  I simply 
> worked under the existing smp_call_function[_single]() API.
> 
> Using the smp_call_functions is critical design factor, however.  I 
> really want clients of this function to seamlessly transition to 
> threaded mode. [...]

well, 'clients' of this function are low-level architectural bits like 
the scheduler and the TLB flush code which stays atomic nevertheless. 
smp_call_function() is _not_ a true generic framework and to 'thread' it 
is wrong and misplaced and leads to the kind of over-complification that 
your patch shows. Please work based on the workqueue APIs.

	Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/