From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 813E06B02A4 for ; Mon, 12 Jul 2010 18:08:04 -0400 (EDT) Date: Tue, 13 Jul 2010 01:08:01 +0300 From: "Kirill A. Shutemov" Subject: Re: [patch 071/149] ARM: 6166/1: Proper prefetch abort handling on pre-ARMv6 Message-ID: <20100712220801.GA28926@shutemov.name> References: <20100701221728.GA12187@suse.de> <20100701222541.GB10481@shutemov.name> <20100701224837.GA27389@flint.arm.linux.org.uk> <20100701225911.GC10481@shutemov.name> <20100701231207.GB27389@flint.arm.linux.org.uk> <20100706130618.GA14177@shutemov.name> <20100706225815.GA21834@flint.arm.linux.org.uk> <20100707085601.GA18732@shutemov.name> <20100707223417.GA22673@n2100.arm.linux.org.uk> <20100708113122.GA23854@shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100708113122.GA23854@shutemov.name> Sender: owner-linux-mm@kvack.org To: Russell King - ARM Linux Cc: Siarhei Siamashka , Anfei Zhou , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Alexander Shishkin , alan@lxorguk.ukuu.org.uk, linux-arm-kernel@lists.infradead.org List-ID: On Thu, Jul 08, 2010 at 02:31:22PM +0300, Kirill A. Shutemov wrote: > On Wed, Jul 07, 2010 at 11:34:18PM +0100, Russell King - ARM Linux wrote: > > On Wed, Jul 07, 2010 at 11:56:01AM +0300, Kirill A. Shutemov wrote: > > > But it seems that the problem is more global. Potentially, any of > > > pmd_none() check may produce false results. I don't see an easy way to fix > > > it. > > > > It isn't. We normally guarantee that we always fill on both L1 entries. > > The only exception is for the mappings specified via create_mapping() > > which is used for the static platform mappings. > > Why do not to change create_mapping() to follow the same rules? > I mean, create sections only if it asked for 2*SECTION_SIZE with > appropriate alignment. It reduces number of section mappings, but, > probably, will be a bit cleaner and less error-prune. > > > > Does Linux VM still expect one PTE table per page? > > > > Yes, and as far as I can see probably always will. Hence why we need > > to put two L1 entries in one page and lie to the kernel about the sizes > > of the hardware entries. > > Another option is leave half of page with PTE table free. Is it very bad > idea? > > How other architectures handle it? Or only on ARM PTL table size is less > than page size? Russell, any comments? I would like to fix it in a right way. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org