From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 699CCC2BA83 for ; Wed, 12 Feb 2020 17:34:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E82A20873 for ; Wed, 12 Feb 2020 17:34:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727361AbgBLRea (ORCPT ); Wed, 12 Feb 2020 12:34:30 -0500 Received: from relay.sw.ru ([185.231.240.75]:43188 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbgBLRea (ORCPT ); Wed, 12 Feb 2020 12:34:30 -0500 Received: from [192.168.15.107] by relay.sw.ru with esmtp (Exim 4.92.3) (envelope-from ) id 1j1vtZ-0007GB-Pk; Wed, 12 Feb 2020 20:33:53 +0300 Subject: Re: [PATCH v6 4/6] block: Add support for REQ_ALLOCATE flag To: "Darrick J. Wong" Cc: martin.petersen@oracle.com, bob.liu@oracle.com, axboe@kernel.dk, agk@redhat.com, snitzer@redhat.com, dm-devel@redhat.com, song@kernel.org, tytso@mit.edu, adilger.kernel@dilger.ca, Chaitanya.Kulkarni@wdc.com, ming.lei@redhat.com, osandov@fb.com, jthumshirn@suse.de, minwoo.im.dev@gmail.com, damien.lemoal@wdc.com, andrea.parri@amarulasolutions.com, hare@suse.com, tj@kernel.org, ajay.joshi@wdc.com, sagi@grimberg.me, dsterba@suse.com, bvanassche@acm.org, dhowells@redhat.com, asml.silence@gmail.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org References: <158132703141.239613.3550455492676290009.stgit@localhost.localdomain> <158132723311.239613.5269033996109738831.stgit@localhost.localdomain> <20200212165837.GL6874@magnolia> From: Kirill Tkhai Message-ID: <092f2dc2-7bb7-d5dd-9a54-e9430940ece9@virtuozzo.com> Date: Wed, 12 Feb 2020 20:33:52 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <20200212165837.GL6874@magnolia> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hi, Darrick, On 12.02.2020 19:58, Darrick J. Wong wrote: > On Mon, Feb 10, 2020 at 12:33:53PM +0300, Kirill Tkhai wrote: >> This adds support for REQ_ALLOCATE extension of REQ_OP_WRITE_ZEROES >> operation, which encourages a block device driver to just allocate >> blocks (or mark them allocated) instead of actual blocks zeroing. >> REQ_ALLOCATE is aimed to be used for network filesystems providing >> a block device interface. Also, block devices, which map a file >> on other filesystem (like loop), may use this for less fragmentation >> and batching fallocate() requests. Hypervisors like QEMU may >> introduce optimizations of clusters allocations based on this. >> >> BLKDEV_ZERO_ALLOCATE is a new corresponding flag for >> blkdev_issue_zeroout(). >> >> Stacking devices start from zero max_allocate_sectors limit for now, >> and the support is going to be implemented separate for each device >> in the future. >> >> Signed-off-by: Kirill Tkhai >> Reviewed-by: Bob Liu >> --- >> block/blk-lib.c | 17 ++++++++++------- >> block/blk-settings.c | 4 ++++ >> fs/block_dev.c | 4 ++++ >> include/linux/blk_types.h | 5 ++++- >> include/linux/blkdev.h | 13 ++++++++++--- >> 5 files changed, 32 insertions(+), 11 deletions(-) >> >> diff --git a/block/blk-lib.c b/block/blk-lib.c >> index 3e38c93cfc53..9cd6f86523ba 100644 >> --- a/block/blk-lib.c >> +++ b/block/blk-lib.c >> @@ -214,7 +214,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, >> struct bio **biop, unsigned flags) >> { >> struct bio *bio = *biop; >> - unsigned int max_write_zeroes_sectors; >> + unsigned int max_write_zeroes_sectors, req_flags = 0; >> struct request_queue *q = bdev_get_queue(bdev); >> >> if (!q) >> @@ -224,18 +224,21 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev, >> return -EPERM; >> >> /* Ensure that max_write_zeroes_sectors doesn't overflow bi_size */ >> - max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, 0); >> + max_write_zeroes_sectors = bdev_write_zeroes_sectors(bdev, flags); >> >> if (max_write_zeroes_sectors == 0) >> return -EOPNOTSUPP; >> >> + if (flags & BLKDEV_ZERO_NOUNMAP) >> + req_flags |= REQ_NOUNMAP; >> + if (flags & BLKDEV_ZERO_ALLOCATE) >> + req_flags |= REQ_ALLOCATE|REQ_NOUNMAP; >> + >> while (nr_sects) { >> bio = blk_next_bio(bio, 0, gfp_mask); >> bio->bi_iter.bi_sector = sector; >> bio_set_dev(bio, bdev); >> - bio->bi_opf = REQ_OP_WRITE_ZEROES; >> - if (flags & BLKDEV_ZERO_NOUNMAP) >> - bio->bi_opf |= REQ_NOUNMAP; >> + bio->bi_opf = REQ_OP_WRITE_ZEROES | req_flags; >> >> if (nr_sects > max_write_zeroes_sectors) { >> bio->bi_iter.bi_size = max_write_zeroes_sectors << 9; >> @@ -362,7 +365,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, >> sector_t bs_mask; >> struct bio *bio; >> struct blk_plug plug; >> - bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, 0); >> + bool try_write_zeroes = !!bdev_write_zeroes_sectors(bdev, flags); >> >> bs_mask = (bdev_logical_block_size(bdev) >> 9) - 1; >> if ((sector | nr_sects) & bs_mask) >> @@ -391,7 +394,7 @@ int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, >> try_write_zeroes = false; >> goto retry; >> } >> - if (!bdev_write_zeroes_sectors(bdev, 0)) { >> + if (!bdev_write_zeroes_sectors(bdev, flags)) { >> /* >> * Zeroing offload support was indicated, but the >> * device reported ILLEGAL REQUEST (for some devices >> diff --git a/block/blk-settings.c b/block/blk-settings.c >> index c8eda2e7b91e..8d5df9d37239 100644 >> --- a/block/blk-settings.c >> +++ b/block/blk-settings.c >> @@ -48,6 +48,7 @@ void blk_set_default_limits(struct queue_limits *lim) >> lim->chunk_sectors = 0; >> lim->max_write_same_sectors = 0; >> lim->max_write_zeroes_sectors = 0; >> + lim->max_allocate_sectors = 0; >> lim->max_discard_sectors = 0; >> lim->max_hw_discard_sectors = 0; >> lim->discard_granularity = 0; >> @@ -83,6 +84,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) >> lim->max_dev_sectors = UINT_MAX; >> lim->max_write_same_sectors = UINT_MAX; >> lim->max_write_zeroes_sectors = UINT_MAX; >> + lim->max_allocate_sectors = 0; >> } >> EXPORT_SYMBOL(blk_set_stacking_limits); >> >> @@ -506,6 +508,8 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, >> b->max_write_same_sectors); >> t->max_write_zeroes_sectors = min(t->max_write_zeroes_sectors, >> b->max_write_zeroes_sectors); >> + t->max_allocate_sectors = min(t->max_allocate_sectors, >> + b->max_allocate_sectors); >> t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); >> >> t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, >> diff --git a/fs/block_dev.c b/fs/block_dev.c >> index 69bf2fb6f7cd..1ffef894b3bd 100644 >> --- a/fs/block_dev.c >> +++ b/fs/block_dev.c >> @@ -2122,6 +2122,10 @@ static long blkdev_fallocate(struct file *file, int mode, loff_t start, >> error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, >> GFP_KERNEL, BLKDEV_ZERO_NOFALLBACK); >> break; >> + case FALLOC_FL_KEEP_SIZE: >> + error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, >> + GFP_KERNEL, BLKDEV_ZERO_ALLOCATE | BLKDEV_ZERO_NOFALLBACK); > > I think this should be ^^^ indented to match the other calls. The only idea I have about this is something like the below. But the below is over 90 char... error = blkdev_issue_zeroout(bdev, start >> 9, len >> 9, GFP_KERNEL, BLKDEV_ZERO_ALLOCATE | BLKDEV_ZERO_NOFALLBACK); Could you please clarify what you mean? >> + break; >> case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: >> error = blkdev_issue_discard(bdev, start >> 9, len >> 9, >> GFP_KERNEL, 0); >> diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h >> index 70254ae11769..86accd2caa4e 100644 >> --- a/include/linux/blk_types.h >> +++ b/include/linux/blk_types.h >> @@ -335,7 +335,9 @@ enum req_flag_bits { >> >> /* command specific flags for REQ_OP_WRITE_ZEROES: */ >> __REQ_NOUNMAP, /* do not free blocks when zeroing */ >> - >> + __REQ_ALLOCATE, /* only notify about allocated blocks, >> + * and do not actually zero them > > "only notify"? Is someone getting a notification? Or are we simply > "notifying" the device that it must ensure allocated blocks? > > If it's that last one, then perhaps this should be reworded: > > /* > * Ensure the LBA range is backed by physical storage > * without writing zeroes to the blocks. > */ Sounds good. >> + */ >> __REQ_HIPRI, >> >> /* for driver use */ >> @@ -362,6 +364,7 @@ enum req_flag_bits { >> #define REQ_CGROUP_PUNT (1ULL << __REQ_CGROUP_PUNT) >> >> #define REQ_NOUNMAP (1ULL << __REQ_NOUNMAP) >> +#define REQ_ALLOCATE (1ULL << __REQ_ALLOCATE) >> #define REQ_HIPRI (1ULL << __REQ_HIPRI) >> >> #define REQ_DRV (1ULL << __REQ_DRV) >> diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h >> index 55a714161684..40707f980a2e 100644 >> --- a/include/linux/blkdev.h >> +++ b/include/linux/blkdev.h >> @@ -336,6 +336,7 @@ struct queue_limits { >> unsigned int max_hw_discard_sectors; >> unsigned int max_write_same_sectors; >> unsigned int max_write_zeroes_sectors; >> + unsigned int max_allocate_sectors; >> unsigned int discard_granularity; >> unsigned int discard_alignment; >> >> @@ -990,6 +991,8 @@ static inline struct bio_vec req_bvec(struct request *rq) >> static inline unsigned int blk_queue_get_max_write_zeroes_sectors( >> struct request_queue *q, unsigned int op_flags) >> { >> + if (op_flags & REQ_ALLOCATE) >> + return q->limits.max_allocate_sectors; >> return q->limits.max_write_zeroes_sectors; >> } >> >> @@ -1226,6 +1229,7 @@ extern int __blkdev_issue_discard(struct block_device *bdev, sector_t sector, >> >> #define BLKDEV_ZERO_NOUNMAP (1 << 0) /* do not free blocks */ >> #define BLKDEV_ZERO_NOFALLBACK (1 << 1) /* don't write explicit zeroes */ >> +#define BLKDEV_ZERO_ALLOCATE (1 << 2) /* allocate range of blocks */ >> >> extern int __blkdev_issue_zeroout(struct block_device *bdev, sector_t sector, >> sector_t nr_sects, gfp_t gfp_mask, struct bio **biop, >> @@ -1430,10 +1434,13 @@ static inline unsigned int bdev_write_zeroes_sectors(struct block_device *bdev, >> { >> struct request_queue *q = bdev_get_queue(bdev); >> >> - if (q) >> - return q->limits.max_write_zeroes_sectors; >> + if (!q) >> + return 0; >> >> - return 0; >> + if (flags & BLKDEV_ZERO_ALLOCATE) >> + return q->limits.max_allocate_sectors; >> + else >> + return q->limits.max_write_zeroes_sectors; >> } >> >> static inline enum blk_zoned_model bdev_zoned_model(struct block_device *bdev) >> >> Thanks, Kirill