From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756387AbbJ1WJo (ORCPT ); Wed, 28 Oct 2015 18:09:44 -0400 Received: from mga03.intel.com ([134.134.136.65]:59845 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755473AbbJ1WJn (ORCPT ); Wed, 28 Oct 2015 18:09:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,211,1444719600"; d="scan'208";a="805908866" From: Ross Zwisler To: linux-kernel@vger.kernel.org Cc: Ross Zwisler , "H. Peter Anvin" , Dan Williams , Ingo Molnar , Thomas Gleixner , linux-nvdimm@ml01.01.org, x86@kernel.org, Dave Chinner , Jan Kara Subject: [PATCH 0/2] "big hammer" for DAX msync/fsync correctness Date: Wed, 28 Oct 2015 16:09:34 -0600 Message-Id: <1446070176-14568-1-git-send-email-ross.zwisler@linux.intel.com> X-Mailer: git-send-email 2.1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This series implements the very slow but correct handling for blkdev_issue_flush() with DAX mappings, as discussed here: https://lkml.org/lkml/2015/10/26/116 I don't think that we can actually do the on_each_cpu(sync_cache, ...); ...where sync_cache is something like: cache_disable(); wbinvd(); pcommit(); cache_enable(); solution as proposed by Dan because WBINVD + PCOMMIT doesn't guarantee that your writes actually make it durably onto the DIMMs. I believe you really do need to loop through the cache lines, flush them with CLWB, then fence and PCOMMIT. I do worry that the cost of blindly flushing the entire PMEM namespace on each fsync or msync will be prohibitively expensive, and that we'll by very incentivized to move to the radix tree based dirty page tracking as soon as possible. :) Ross Zwisler (2): pmem: add wb_cache_pmem() to the PMEM API pmem: Add simple and slow fsync/msync support arch/x86/include/asm/pmem.h | 11 ++++++----- drivers/nvdimm/pmem.c | 10 +++++++++- include/linux/pmem.h | 22 +++++++++++++++++++++- 3 files changed, 36 insertions(+), 7 deletions(-) -- 2.1.0