From mboxrd@z Thu Jan 1 00:00:00 1970 From: Borislav Petkov Subject: Re: [PATCH v10 11/12] x86, mm, pat: Refactor !pat_enabled handling Date: Fri, 29 May 2015 10:58:42 +0200 Message-ID: <20150529085842.GA31435@pd.tnic> References: <1432739944-22633-1-git-send-email-toshi.kani@hp.com> <1432739944-22633-12-git-send-email-toshi.kani@hp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Return-path: Content-Disposition: inline In-Reply-To: <1432739944-22633-12-git-send-email-toshi.kani@hp.com> Sender: linux-kernel-owner@vger.kernel.org To: Toshi Kani Cc: hpa@zytor.com, tglx@linutronix.de, mingo@redhat.com, akpm@linux-foundation.org, arnd@arndb.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org, x86@kernel.org, linux-nvdimm@lists.01.org, jgross@suse.com, stefan.bader@canonical.com, luto@amacapital.net, hmh@hmh.eng.br, yigal@plexistor.com, konrad.wilk@oracle.com, Elliott@hp.com, mcgrof@suse.com, hch@lst.de List-Id: linux-mm.kvack.org On Wed, May 27, 2015 at 09:19:03AM -0600, Toshi Kani wrote: > This patch refactors the !pat_enabled code paths and integrates Please refrain from using such empty phrases like "This patch does this and that" in your commit messages - it is implicitly obvious that it is "this patch" when one reads it. > them into the PAT abstraction code. The PAT table is emulated by > corresponding to the two cache attribute bits, PWT (Write Through) > and PCD (Cache Disable). The emulated PAT table is the same as the > BIOS default setup when the system has PAT but the "nopat" boot > option is specified. The emulated PAT table is also used when > MSR_IA32_CR_PAT returns 0 (9d34cfdf4). 9d34cfdf4 - what is that thing? A commit message? If so, we quote them like this: 9d34cfdf4796 ("x86: Don't rely on VMWare emulating PAT MSR correctly") note the 12 chars length of the commit id. > Signed-off-by: Toshi Kani > Reviewed-by: Juergen Gross > --- > arch/x86/mm/init.c | 6 ++-- > arch/x86/mm/iomap_32.c | 12 ++++--- > arch/x86/mm/ioremap.c | 10 +----- > arch/x86/mm/pageattr.c | 6 ---- > arch/x86/mm/pat.c | 77 +++++++++++++++++++++++++++++------------------- > 5 files changed, 57 insertions(+), 54 deletions(-) So I started applying your pile and everything was ok-ish until I came about this trainwreck. You have a lot of changes in here, the commit message is certainly lacking sufficient explanation as to why and this patch is changing stuff which the previous one adds. So a lot of unnecesary code movement. Then you have stuff like this: + } else if (!cpu_has_pat && pat_enabled) { How can a CPU not have PAT but have it enabled?!? So this is not how we do patchsets. Please do the cleanups *first*. Do them in small, self-contained changes explaining *why* you're doing them. *Then* add the new functionality, .i.e. the WT. Oh, and when you do your next version, do the patches against tip/master because there are a bunch of changes in the PAT code already. Thanks. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --