Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752218AbdHHGvQ (ORCPT ); Tue, 8 Aug 2017 02:51:16 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:57981 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752047AbdHHGud (ORCPT ); Tue, 8 Aug 2017 02:50:33 -0400 X-Original-SENDERIP: 156.147.1.127 X-Original-MAILFROM: minchan@kernel.org X-Original-SENDERIP: 10.177.220.163 X-Original-MAILFROM: minchan@kernel.org From: Minchan Kim To: Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Ross Zwisler , "karam . lee" , seungho1.park@lge.com, Matthew Wilcox , Christoph Hellwig , Dan Williams , Dave Chinner , jack@suse.cz, Jens Axboe , Vishal Verma , linux-nvdimm@lists.01.org, kernel-team , Minchan Kim Subject: [PATCH v1 1/6] bdi: introduce BDI_CAP_SYNC Date: Tue, 8 Aug 2017 15:50:19 +0900 Message-Id: <1502175024-28338-2-git-send-email-minchan@kernel.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1502175024-28338-1-git-send-email-minchan@kernel.org> References: <1502175024-28338-1-git-send-email-minchan@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4662 Lines: 122 By discussion[1], we will replace rw_page devices with on-stack-bio. For such super-fast devices to be detected, this patch introduces BDI_CAP_SYNC which means synchronous IO would be more efficient for asnychronous IO and uses the flags to brd, zram, btt and pmem. [1] lkml.kernel.org/r/<20170728165604.10455-1-ross.zwisler@linux.intel.com> Signed-off-by: Minchan Kim --- drivers/block/brd.c | 2 ++ drivers/block/zram/zram_drv.c | 2 +- drivers/nvdimm/btt.c | 2 ++ drivers/nvdimm/pmem.c | 2 ++ include/linux/backing-dev.h | 7 +++++++ 5 files changed, 14 insertions(+), 1 deletion(-) diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 293250582f00..97d4e1679de7 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -20,6 +20,7 @@ #include #include #include +#include #ifdef CONFIG_BLK_DEV_RAM_DAX #include #include @@ -436,6 +437,7 @@ static struct brd_device *brd_alloc(int i) disk->flags = GENHD_FL_EXT_DEVT; sprintf(disk->disk_name, "ram%d", i); set_capacity(disk, rd_size * 2); + disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNC; #ifdef CONFIG_BLK_DEV_RAM_DAX queue_flag_set_unlocked(QUEUE_FLAG_DAX, brd->brd_queue); diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index bbbc2f230b8e..3eda88d0ca95 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1577,7 +1577,7 @@ static int zram_add(void) blk_queue_max_write_zeroes_sectors(zram->disk->queue, UINT_MAX); zram->disk->queue->backing_dev_info->capabilities |= - BDI_CAP_STABLE_WRITES; + (BDI_CAP_STABLE_WRITES | BDI_CAP_SYNC); add_disk(zram->disk); ret = sysfs_create_group(&disk_to_dev(zram->disk)->kobj, diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c index e10d3300b64c..16f60351e4fd 100644 --- a/drivers/nvdimm/btt.c +++ b/drivers/nvdimm/btt.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "btt.h" #include "nd.h" @@ -1273,6 +1274,7 @@ static int btt_blk_init(struct btt *btt) btt->btt_disk->private_data = btt; btt->btt_disk->queue = btt->btt_queue; btt->btt_disk->flags = GENHD_FL_EXT_DEVT; + btt->btt_disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNC; blk_queue_make_request(btt->btt_queue, btt_make_request); blk_queue_logical_block_size(btt->btt_queue, btt->sector_size); diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index b5f04559a497..e1704099b5cc 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "pmem.h" #include "pfn.h" #include "nd.h" @@ -379,6 +380,7 @@ static int pmem_attach_disk(struct device *dev, disk->fops = &pmem_fops; disk->queue = q; disk->flags = GENHD_FL_EXT_DEVT; + disk->queue->backing_dev_info->capabilities |= BDI_CAP_SYNC; nvdimm_namespace_disk_name(ndns, disk->disk_name); set_capacity(disk, (pmem->size - pmem->pfn_pad - pmem->data_offset) / 512); diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h index 854e1bdd0b2a..397ee71763d7 100644 --- a/include/linux/backing-dev.h +++ b/include/linux/backing-dev.h @@ -123,6 +123,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); * BDI_CAP_STRICTLIMIT: Keep number of dirty pages below bdi threshold. * * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback. + * BDI_CAP_SYNC: Device is so fast that asynchronous IO would be inefficient. */ #define BDI_CAP_NO_ACCT_DIRTY 0x00000001 #define BDI_CAP_NO_WRITEBACK 0x00000002 @@ -130,6 +131,7 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio); #define BDI_CAP_STABLE_WRITES 0x00000008 #define BDI_CAP_STRICTLIMIT 0x00000010 #define BDI_CAP_CGROUP_WRITEBACK 0x00000020 +#define BDI_CAP_SYNC 0x00000040 #define BDI_CAP_NO_ACCT_AND_WRITEBACK \ (BDI_CAP_NO_WRITEBACK | BDI_CAP_NO_ACCT_DIRTY | BDI_CAP_NO_ACCT_WB) @@ -177,6 +179,11 @@ long wait_iff_congested(struct pglist_data *pgdat, 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 bool bdi_cap_synchronous_io(struct backing_dev_info *bdi) +{ + return bdi->capabilities & BDI_CAP_SYNC; +} + static inline bool bdi_cap_stable_pages_required(struct backing_dev_info *bdi) { return bdi->capabilities & BDI_CAP_STABLE_WRITES; -- 2.7.4