From patchwork Thu Dec 10 02:37:20 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dan Williams X-Patchwork-Id: 7814121 Return-Path: X-Original-To: patchwork-linux-nvdimm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 2C4109F349 for ; Thu, 10 Dec 2015 02:37:50 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 63993204FB for ; Thu, 10 Dec 2015 02:37:49 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8DA0220456 for ; Thu, 10 Dec 2015 02:37:48 +0000 (UTC) Received: from ml01.vlan14.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 821CA1A21EF; Wed, 9 Dec 2015 18:37:48 -0800 (PST) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by ml01.01.org (Postfix) with ESMTP id AE5D21A21EF for ; Wed, 9 Dec 2015 18:37:47 -0800 (PST) Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga102.jf.intel.com with ESMTP; 09 Dec 2015 18:37:48 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,406,1444719600"; d="scan'208";a="868494668" Received: from dwillia2-desk3.jf.intel.com ([10.54.39.136]) by orsmga002.jf.intel.com with ESMTP; 09 Dec 2015 18:37:47 -0800 Subject: [-mm PATCH v2 02/25] dax: increase granularity of dax_clear_blocks() operations From: Dan Williams To: akpm@linux-foundation.org Date: Wed, 09 Dec 2015 18:37:20 -0800 Message-ID: <20151210023720.30368.14658.stgit@dwillia2-desk3.jf.intel.com> In-Reply-To: <20151210023708.30368.92962.stgit@dwillia2-desk3.jf.intel.com> References: <20151210023708.30368.92962.stgit@dwillia2-desk3.jf.intel.com> User-Agent: StGit/0.17.1-9-g687f MIME-Version: 1.0 Cc: linux-mm@kvack.org, Jan Kara , linux-nvdimm@lists.01.org X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Spam-Status: No, score=-2.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_LOW, T_RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP dax_clear_blocks is currently performing a cond_resched() after every PAGE_SIZE memset. We need not check so frequently, for example md-raid only calls cond_resched() at stripe granularity. Also, in preparation for introducing a dax_map_atomic() operation that temporarily pins a dax mapping move the call to cond_resched() to the outer loop. The worst case latency between calls to cond_resched() after this change is 500us the average latency is 133us. This is up from a 10us max and 4us average. Reviewed-by: Jan Kara Reviewed-by: Jeff Moyer Signed-off-by: Dan Williams --- fs/dax.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 19492cc65a30..11721c0fc127 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -28,6 +28,7 @@ #include #include #include +#include /* * dax_clear_blocks() is called from within transaction context from XFS, @@ -43,24 +44,17 @@ int dax_clear_blocks(struct inode *inode, sector_t block, long size) do { void __pmem *addr; unsigned long pfn; - long count; + long count, sz; count = bdev_direct_access(bdev, sector, &addr, &pfn, size); if (count < 0) return count; - BUG_ON(size < count); - while (count > 0) { - unsigned pgsz = PAGE_SIZE - offset_in_page(addr); - if (pgsz > count) - pgsz = count; - clear_pmem(addr, pgsz); - addr += pgsz; - size -= pgsz; - count -= pgsz; - BUG_ON(pgsz & 511); - sector += pgsz / 512; - cond_resched(); - } + sz = min_t(long, count, SZ_128K); + clear_pmem(addr, sz); + size -= sz; + BUG_ON(sz & 511); + sector += sz / 512; + cond_resched(); } while (size); wmb_pmem();