Re: [patch 2/2] reduce tlb/cache flush times of agpgart memory allocation

From: Ingo Molnar <mingo@elte.hu>
To: "Li, Shaohua" <shaohua.li@intel.com>
Cc: Arjan van de Ven <arjan@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	"airlied@linux.ie" <airlied@linux.ie>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@redhat.com>,
	"Siddha, Suresh B" <suresh.b.siddha@intel.com>,
	"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [patch 2/2] reduce tlb/cache flush times of agpgart memory allocation
Date: Mon, 18 Aug 2008 10:03:44 +0200	[thread overview]
Message-ID: <20080818080344.GK30694@elte.hu> (raw)
In-Reply-To: <76780B19A496DC4B80439008DAD7076C0CF9E403@PDSMSX501.ccr.corp.intel.com>

* Li, Shaohua <shaohua.li@intel.com> wrote:

> > it would be great if you had time to update his patch and this to 
> > it...
>
> I'll do it soon.

great! Please do it as a delta patch against tip/master:

   http://people.redhat.com/mingo/tip.git/README

as your first two patches are being tested already:

 466ae83: reduce tlb/cache flush times of agpgart memory allocation
 1ac2f7d: introduce two APIs for page attribute

[ but it can all only go upstream once the observations from Arjan have
  been addressed. ]

> > and the logic probably should be "if there's more than X pags in the 
> > the array, just use wbinvd". Although wbinvd is very painful if you 
> > have 12Mb of cache and you wipe it for all cores in the system ;-(
>
> This might not be that bad, changing attribute isn't frequently used.

dont some X/DRM drivers do it for a wide range of GX ops?

	Ingo