From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH/RFC] Rework ptep_set_access_flags and fix sun4c From: Benjamin Herrenschmidt In-Reply-To: References: <20070509231937.ea254c26.akpm@linux-foundation.org> <1178778583.14928.210.camel@localhost.localdomain> <20070510.001234.126579706.davem@davemloft.net> <1179176845.32247.107.camel@localhost.localdomain> <1179212184.32247.163.camel@localhost.localdomain> <1179757647.6254.235.camel@localhost.localdomain> <1179815339.32247.799.camel@localhost.localdomain> <1179874748.32247.868.camel@localhost.localdomain> Content-Type: text/plain Date: Wed, 23 May 2007 14:21:45 +1000 Message-Id: <1179894105.32247.904.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: "Tom \"spot\" Callaway" , David Miller , akpm@linux-foundation.org, mark@mtfhpc.demon.co.uk, linuxppc-dev@ozlabs.org, wli@holomorphy.com, linux-mm@kvack.org, andrea@suse.de, sparclinux@vger.kernel.org List-ID: On Wed, 2007-05-23 at 05:03 +0100, Hugh Dickins wrote: > > No, I wasn't meaning the optimization, but the significance of the > boolean __changed that's returned. If ptep_set_access_flags does > not change the pte (because !dirty or !safely_writable or whatever > that arch calls it), then ideally it ought to return false. Hrm... I prefer keeping the existing semantics. The old code used to always update_mmu_cache() on those archs and I'd rather let it continue do so unless the arch maintainer who knows better changes it :-) > But it doesn't affect correctness if it sometimes says true not > false, and these arches happen to have an empty update_mmu_cache > (with lazy_mmu_prot_update currently under separate review), and > what you have follows what was already being done, and sun4c > already has to "lie": so it's rather theoretical. Ok. Cheers, Ben. -- 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