linux-kernel - Re: kmap_atomic_pfn for PCI BAR access?

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]

Message-ID: <20080626033614.0ef55f9d@infradead.org>
Date:	Thu, 26 Jun 2008 03:36:14 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	Dave Airlie <airlied@...ux.ie>
Cc:	Jeremy Fitzhardinge <jeremy@...p.org>,
	Keith Packard <keithp@...thp.com>,
	Dave Airlie <airlied@...il.com>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: kmap_atomic_pfn for PCI BAR access?

On Thu, 26 Jun 2008 07:02:15 +0100 (IST)
Dave Airlie <airlied@...ux.ie> wrote:

> > >   
> > 
> > Anything that does any kind of pagetable manipulation needs to do
> > tlb flushes. kunmap_atomic handles the flushing.
> 
> It doesn't however need to do an IPI dance which is the worst part of 
> doing a tlb flush on SMP machines.
> 
> flushing local CPU tlbs is bad, but doing IPIs and waiting for
> everyone else is brutal.

but you only do IPI's for the multithreaded case to cpus where you're
running; otoh I guess games are multithreaded nowadays

> 
> Dave.


-- 
If you want to reach me at my work email, use arjan@...ux.intel.com
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
--
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/