From patchwork Wed Nov 21 02:00:34 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Darrick Wong X-Patchwork-Id: 200537 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id E57D92C00A8 for ; Wed, 21 Nov 2012 13:01:25 +1100 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753957Ab2KUCBD (ORCPT ); Tue, 20 Nov 2012 21:01:03 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:21682 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753916Ab2KUCBA (ORCPT ); Tue, 20 Nov 2012 21:01:00 -0500 Received: from ucsinet21.oracle.com (ucsinet21.oracle.com [156.151.31.93]) by userp1040.oracle.com (Sentrion-MTA-4.2.2/Sentrion-MTA-4.2.2) with ESMTP id qAL20cXV031407 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Wed, 21 Nov 2012 02:00:39 GMT Received: from acsmt357.oracle.com (acsmt357.oracle.com [141.146.40.157]) by ucsinet21.oracle.com (8.14.4+Sun/8.14.4) with ESMTP id qAL20aDb002684 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Wed, 21 Nov 2012 02:00:37 GMT Received: from abhmt117.oracle.com (abhmt117.oracle.com [141.146.116.69]) by acsmt357.oracle.com (8.12.11.20060308/8.12.11) with ESMTP id qAL20aKu026541; Tue, 20 Nov 2012 20:00:36 -0600 Received: from localhost (/67.171.138.228) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 20 Nov 2012 18:00:36 -0800 Subject: [PATCH 1/4] bdi: Track users that require stable page writes To: axboe@kernel.dk, lucho@ionkov.net, jack@suse.cz, ericvh@gmail.com, tytso@mit.edu, rminnich@sandia.gov, viro@zeniv.linux.org.uk From: "Darrick J. Wong" Cc: martin.petersen@oracle.com, neilb@suse.de, david@fromorbit.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, adilger.kernel@dilger.ca, bharrosh@panasas.com, jlayton@samba.org, v9fs-developer@lists.sourceforge.net, linux-ext4@vger.kernel.org Date: Tue, 20 Nov 2012 18:00:34 -0800 Message-ID: <20121121020034.10225.51692.stgit@blackbox.djwong.org> In-Reply-To: <20121121020027.10225.43206.stgit@blackbox.djwong.org> References: <20121121020027.10225.43206.stgit@blackbox.djwong.org> User-Agent: StGit/0.15 MIME-Version: 1.0 X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org This creates a per-backing-device counter that tracks the number of users which require pages to be held immutable during writeout. Eventually it will be used to waive wait_for_page_writeback() if nobody requires stable pages. Signed-off-by: Darrick J. Wong --- Documentation/ABI/testing/sysfs-class-bdi | 7 ++++++ block/blk-integrity.c | 4 +++ include/linux/backing-dev.h | 16 +++++++++++++ include/linux/blkdev.h | 15 ++++++++++++ mm/backing-dev.c | 36 +++++++++++++++++++++++++++++ 5 files changed, 78 insertions(+) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/Documentation/ABI/testing/sysfs-class-bdi b/Documentation/ABI/testing/sysfs-class-bdi index 5f50097..218a618 100644 --- a/Documentation/ABI/testing/sysfs-class-bdi +++ b/Documentation/ABI/testing/sysfs-class-bdi @@ -48,3 +48,10 @@ max_ratio (read-write) most of the write-back cache. For example in case of an NFS mount that is prone to get stuck, or a FUSE mount which cannot be trusted to play fair. + +stable_pages_required (read-write) + + If set, the backing device requires that all pages comprising a write + request must not be changed until writeout is complete. The system + administrator can turn this on if the hardware does not do so already. + However, once enabled, this flag cannot be disabled. diff --git a/block/blk-integrity.c b/block/blk-integrity.c index da2a818..cf2dd95 100644 --- a/block/blk-integrity.c +++ b/block/blk-integrity.c @@ -420,6 +420,8 @@ int blk_integrity_register(struct gendisk *disk, struct blk_integrity *template) } else bi->name = bi_unsupported_name; + queue_require_stable_pages(disk->queue); + return 0; } EXPORT_SYMBOL(blk_integrity_register); @@ -438,6 +440,8 @@ void blk_integrity_unregister(struct gendisk *disk) if (!disk || !disk->integrity) return; + queue_unrequire_stable_pages(disk->queue); + bi = disk->integrity; kobject_uevent(&bi->kobj, KOBJ_REMOVE); diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 2a9a9ab..af19704 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -253,6 +253,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); #define BDI_CAP_EXEC_MAP 0x00000040 #define BDI_CAP_NO_ACCT_WB 0x00000080 #define BDI_CAP_SWAP_BACKED 0x00000100 +#define BDI_CAP_STABLE_WRITES 0x00000200 #define BDI_CAP_VMFLAGS \ (BDI_CAP_READ_MAP | BDI_CAP_WRITE_MAP | BDI_CAP_EXEC_MAP) @@ -307,6 +308,21 @@ long wait_iff_congested(struct zone *zone, int sync, long timeout); int pdflush_proc_obsolete(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos); +static inline void bdi_require_stable_pages(struct backing_dev_info *bdi) +{ + bdi->capabilities |= BDI_CAP_STABLE_WRITES; +} + +static inline void bdi_unrequire_stable_pages(struct backing_dev_info *bdi) +{ + bdi->capabilities &= ~BDI_CAP_STABLE_WRITES; +} + +static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi) +{ + return bdi->capabilities & BDI_CAP_STABLE_WRITES; +} + static inline bool bdi_cap_writeback_dirty(struct backing_dev_info *bdi) { return !(bdi->capabilities & BDI_CAP_NO_WRITEBACK); diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 1756001..a1c6e91 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -458,6 +458,21 @@ struct request_queue { (1 << QUEUE_FLAG_SAME_COMP) | \ (1 << QUEUE_FLAG_ADD_RANDOM)) +static inline void queue_require_stable_pages(struct request_queue *q) +{ + bdi_require_stable_pages(&q->backing_dev_info); +} + +static inline void queue_unrequire_stable_pages(struct request_queue *q) +{ + bdi_unrequire_stable_pages(&q->backing_dev_info); +} + +static inline int queue_requires_stable_pages(struct request_queue *q) +{ + return bdi_cap_stable_pages_required(&q->backing_dev_info); +} + static inline void queue_lockdep_assert_held(struct request_queue *q) { if (q->queue_lock) diff --git a/mm/backing-dev.c b/mm/backing-dev.c index d3ca2b3..fd6e5b5 100644 --- a/mm/backing-dev.c +++ b/mm/backing-dev.c @@ -221,12 +221,48 @@ static ssize_t max_ratio_store(struct device *dev, } BDI_SHOW(max_ratio, bdi->max_ratio) +static ssize_t stable_pages_required_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + unsigned int spw; + ssize_t ret; + + ret = kstrtouint(buf, 10, &spw); + if (ret < 0) + return ret; + + /* + * SPW could be enabled due to hw requirement, so don't + * let users disable it. + */ + if (bdi_cap_stable_pages_required(bdi) && spw == 0) + return -EINVAL; + + if (spw != 0) + bdi_require_stable_pages(bdi); + + return count; +} + +static ssize_t stable_pages_required_show(struct device *dev, + struct device_attribute *attr, + char *page) +{ + struct backing_dev_info *bdi = dev_get_drvdata(dev); + + return snprintf(page, PAGE_SIZE-1, "%d\n", + bdi_cap_stable_pages_required(bdi) ? 1 : 0); +} + #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store) static struct device_attribute bdi_dev_attrs[] = { __ATTR_RW(read_ahead_kb), __ATTR_RW(min_ratio), __ATTR_RW(max_ratio), + __ATTR_RW(stable_pages_required), __ATTR_NULL, };