From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f51.google.com (mail-pa0-f51.google.com [209.85.220.51]) by kanga.kvack.org (Postfix) with ESMTP id 3A8C56B0035 for ; Wed, 27 Aug 2014 09:15:05 -0400 (EDT) Received: by mail-pa0-f51.google.com with SMTP id ey11so265884pad.24 for ; Wed, 27 Aug 2014 06:15:04 -0700 (PDT) Received: from cam-admin0.cambridge.arm.com (cam-admin0.cambridge.arm.com. [217.140.96.50]) by mx.google.com with ESMTP id ua10si426370pac.145.2014.08.27.06.15.01 for ; Wed, 27 Aug 2014 06:15:02 -0700 (PDT) Date: Wed, 27 Aug 2014 14:14:45 +0100 From: Will Deacon Subject: Re: [PATH V2 1/6] mm: Introduce a general RCU get_user_pages_fast. Message-ID: <20140827131445.GB17601@arm.com> References: <1408635812-31584-1-git-send-email-steve.capper@linaro.org> <1408635812-31584-2-git-send-email-steve.capper@linaro.org> <20140827085442.GD16376@arm.com> <20140827125027.GA7765@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140827125027.GA7765@linaro.org> Sender: owner-linux-mm@kvack.org List-ID: To: Steve Capper Cc: "linux-arm-kernel@lists.infradead.org" , Catalin Marinas , "linux@arm.linux.org.uk" , "linux-arch@vger.kernel.org" , "linux-mm@kvack.org" , "gary.robertson@linaro.org" , "christoffer.dall@linaro.org" , "peterz@infradead.org" , "anders.roxell@linaro.org" , "akpm@linux-foundation.org" , "dann.frazier@canonical.com" , Mark Rutland , "mgorman@suse.de" On Wed, Aug 27, 2014 at 01:50:28PM +0100, Steve Capper wrote: > On Wed, Aug 27, 2014 at 09:54:42AM +0100, Will Deacon wrote: > > On Thu, Aug 21, 2014 at 04:43:27PM +0100, Steve Capper wrote: > > > @@ -672,3 +676,277 @@ struct page *get_dump_page(unsigned long addr) > > > return page; > > > } > > > #endif /* CONFIG_ELF_CORE */ > > > + > > > +#ifdef CONFIG_HAVE_RCU_GUP > > > + > > > +#ifdef __HAVE_ARCH_PTE_SPECIAL > > > > Do we actually require this (pte special) if hugepages are disabled or > > not supported? > > We need this logic if we want use fast_gup on normal pages safely. The special > bit indicates that we should not attempt to take a reference to the underlying > page. > > Huge pages are guaranteed not to be special. Gah, I somehow mixed up sp-litting and sp-ecial. Step away from the computer. In which case, the patch looks fine. You might need to repost with '[PATCH]' instead of '[PATH]', in case you confused people's filters. Will -- 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