From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id B95906B038B for ; Thu, 16 Mar 2017 13:20:55 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id y17so102422959pgh.2 for ; Thu, 16 Mar 2017 10:20:55 -0700 (PDT) Received: from bombadil.infradead.org (bombadil.infradead.org. [65.50.211.133]) by mx.google.com with ESMTPS id z13si4203081pfj.93.2017.03.16.10.20.54 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 Mar 2017 10:20:54 -0700 (PDT) Date: Thu, 16 Mar 2017 18:20:46 +0100 From: Peter Zijlstra Subject: Re: [PATCH 7/7] x86/mm: Switch to generic get_user_page_fast() implementation Message-ID: <20170316172046.sl7j5elg77yjevau@hirez.programming.kicks-ass.net> References: <20170316152655.37789-1-kirill.shutemov@linux.intel.com> <20170316152655.37789-8-kirill.shutemov@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170316152655.37789-8-kirill.shutemov@linux.intel.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Linus Torvalds , Andrew Morton , x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Dave Hansen , "Aneesh Kumar K . V" , Steve Capper , Dann Frazier , Catalin Marinas , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Paul McKenney On Thu, Mar 16, 2017 at 06:26:55PM +0300, Kirill A. Shutemov wrote: > +config HAVE_GENERIC_RCU_GUP > + def_bool y > + Nothing immediately jumped out to me; except that this option might be misnamed. AFAICT that code does not in fact rely on HAVE_RCU_TABLE_FREE; it will happily work with the (x86) broadcast IPI invalidate model, as you show here. Architectures that do not do that obviously need HAVE_RCU_TABLE_FREE, but that is not the point I feel. Also, this code hard relies on IRQ-disable delaying grace periods, which is mostly true I think, but has always been something Paul didn't really want to commit too firmly to. -- 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