linux-kernel - Re: [patch] cpufreq: mark cpufreq_tsc() as core_initcall

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

Date:	Thu, 16 Nov 2006 14:21:57 -0800 (PST)
From:	Linus Torvalds <torvalds@...l.org>
To:	Alan Stern <stern@...land.harvard.edu>
cc:	Thomas Gleixner <tglx@...esys.com>, Ingo Molnar <mingo@...e.hu>,
	LKML <linux-kernel@...r.kernel.org>,
	john stultz <johnstul@...ibm.com>,
	David Miller <davem@...emloft.net>,
	Arjan van de Ven <arjan@...radead.org>,
	Andrew Morton <akpm@...l.org>, Andi Kleen <ak@...e.de>,
	"Paul E. McKenney" <paulmck@...ibm.com>
Subject: Re: [patch] cpufreq: mark cpufreq_tsc() as core_initcall_sync

On Thu, 16 Nov 2006, Alan Stern wrote:
> On Thu, 16 Nov 2006, Linus Torvalds wrote:
> >
> > Paul, it would be _really_ nice to have some way to just initialize 
> > that SRCU thing statically. This kind of crud is just crazy.
> 
> I looked into this back when SRCU was first added.  It's essentially 
> impossible to do it, because the per-cpu memory allocation & usage APIs 
> are completely different for the static and the dynamic cases.

I don't think that's how you'd want to do it.

There's no way to do an initialization of a percpu allocation statically. 
That's pretty obvious.

What I'd suggest instead, is to make the allocation dynamic, and make it 
inside the srcu functions (kind of like I did now, but I did it at a 
higher level).

Doing it at the high level was trivial right now, but we may well end up 
hitting this problem again if people start using SRCU more. Right now I 
suspect the cpufreq notifier is the only thing that uses SRCU, and it 
already showed this problem with SRCU initializers.

So I was more thinking about moving my "one special case high level hack" 
down lower, down to the SRCU level, so that we'll never see _more_ of 
those horrible hacks. We'll still have the hacky thing, but at least it 
will be limited to a single place - the SRCU code itself.

		Linus
-
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/