From: Selva Jove <selvajove@gmail.com>
To: Su Yue <l@damenly.su>
Cc: axboe@kernel.dk, Damien Le Moal <damien.lemoal@wdc.com>,
kch@kernel.org, SelvaKumar S <selvakuma.s1@samsung.com>,
sagi@grimberg.me, snitzer@redhat.com,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
nj.shetty@samsung.com, linux-block@vger.kernel.org,
linux-fsdevel@vger.kernel.org, dm-devel@redhat.com,
joshi.k@samsung.com, javier.gonz@samsung.com,
Keith Busch <kbusch@kernel.org>,
joshiiitr@gmail.com, hch@lst.de
Subject: Re: [RFC PATCH v5 0/4] add simple copy support
Date: Tue, 23 Feb 2021 14:30:29 +0530 [thread overview]
Message-ID: <CAHqX9vbdtNiRvAHSy+1+rD6FEp6zBqmH2P_99P-+dgMZDbMZsA@mail.gmail.com> (raw)
In-Reply-To: <lfbgr3ur.fsf@damenly.su>
Thanks Su Yue. I'll update the link in the next series.
On Mon, Feb 22, 2021 at 12:23 PM Su Yue <l@damenly.su> wrote:
>
>
> On Fri 19 Feb 2021 at 20:45, SelvaKumar S
> <selvakuma.s1@samsung.com> wrote:
>
> > This patchset tries to add support for TP4065a ("Simple Copy
> > Command"),
> > v2020.05.04 ("Ratified")
> >
> > The Specification can be found in following link.
> > https://nvmexpress.org/wp-content/uploads/NVM-Express-1.4-Ratified-TPs-1.zip
> >
>
> 404 not found.
> Should it be
> https://nvmexpress.org/wp-content/uploads/NVM-Express-1.4-Ratified-TPs.zip
> ?
>
> > Simple copy command is a copy offloading operation and is used
> > to copy
> > multiple contiguous ranges (source_ranges) of LBA's to a single
> > destination
> > LBA within the device reducing traffic between host and device.
> >
> > This implementation doesn't add native copy offload support for
> > stacked
> > devices rather copy offload is done through emulation. Possible
> > use
> > cases are F2FS gc and BTRFS relocation/balance.
> >
> > *blkdev_issue_copy* takes source bdev, no of sources, array of
> > source
> > ranges (in sectors), destination bdev and destination offset(in
> > sectors).
> > If both source and destination block devices are same and
> > copy_offload = 1,
> > then copy is done through native copy offloading. Copy emulation
> > is used
> > in other cases.
> >
> > As SCSI XCOPY can take two different block devices and no of
> > source range is
> > equal to 1, this interface can be extended in future to support
> > SCSI XCOPY.
> >
> > For devices supporting native simple copy, attach the control
> > information
> > as payload to the bio and submit to the device. For devices
> > without native
> > copy support, copy emulation is done by reading each source
> > range into memory
> > and writing it to the destination. Caller can choose not to try
> > emulation if copy offload is not supported by setting
> > BLKDEV_COPY_NOEMULATION flag.
> >
> > Following limits are added to queue limits and are exposed in
> > sysfs
> > to userspace
> > - *copy_offload* controls copy_offload. set 0 to disable copy
> > offload, 1 to enable native copy offloading support.
> > - *max_copy_sectors* limits the sum of all source_range length
> > - *max_copy_nr_ranges* limits the number of source ranges
> > - *max_copy_range_sectors* limit the maximum number of sectors
> > that can constitute a single source range.
> >
> > max_copy_sectors = 0 indicates the device doesn't support copy
> > offloading.
> >
> > *copy offload* sysfs entry is configurable and can be used
> > toggle
> > between emulation and native support depending upon the usecase.
> >
> > Changes from v4
> >
> > 1. Extend dm-kcopyd to leverage copy-offload, while copying
> > within the
> > same device. The other approach was to have copy-emulation by
> > moving
> > dm-kcopyd to block layer. But it also required moving core dm-io
> > infra,
> > causing a massive churn across multiple dm-targets.
> >
> > 2. Remove export in bio_map_kern()
> > 3. Change copy_offload sysfs to accept 0 or else
> > 4. Rename copy support flag to QUEUE_FLAG_SIMPLE_COPY
> > 5. Rename payload entries, add source bdev field to be used
> > while
> > partition remapping, remove copy_size
> > 6. Change the blkdev_issue_copy() interface to accept
> > destination and
> > source values in sector rather in bytes
> > 7. Add payload to bio using bio_map_kern() for copy_offload case
> > 8. Add check to return error if one of the source range length
> > is 0
> > 9. Add BLKDEV_COPY_NOEMULATION flag to allow user to not try
> > copy
> > emulation incase of copy offload is not supported. Caller can
> > his use
> > his existing copying logic to complete the io.
> > 10. Bug fix copy checks and reduce size of rcu_lock()
> >
> > Planned for next:
> > - adding blktests
> > - handling larger (than device limits) copy
> > - decide on ioctl interface (man-page etc.)
> >
> > Changes from v3
> >
> > 1. gfp_flag fixes.
> > 2. Export bio_map_kern() and use it to allocate and add pages to
> > bio.
> > 3. Move copy offload, reading to buf, writing from buf to
> > separate functions.
> > 4. Send read bio of copy offload by chaining them and submit
> > asynchronously.
> > 5. Add gendisk->part0 and part->bd_start_sect changes to
> > blk_check_copy().
> > 6. Move single source range limit check to blk_check_copy()
> > 7. Rename __blkdev_issue_copy() to blkdev_issue_copy and remove
> > old helper.
> > 8. Change blkdev_issue_copy() interface generic to accepts
> > destination bdev
> > to support XCOPY as well.
> > 9. Add invalidate_kernel_vmap_range() after reading data for
> > vmalloc'ed memory.
> > 10. Fix buf allocoation logic to allocate buffer for the total
> > size of copy.
> > 11. Reword patch commit description.
> >
> > Changes from v2
> >
> > 1. Add emulation support for devices not supporting copy.
> > 2. Add *copy_offload* sysfs entry to enable and disable
> > copy_offload
> > in devices supporting simple copy.
> > 3. Remove simple copy support for stacked devices.
> >
> > Changes from v1:
> >
> > 1. Fix memory leak in __blkdev_issue_copy
> > 2. Unmark blk_check_copy inline
> > 3. Fix line break in blk_check_copy_eod
> > 4. Remove p checks and made code more readable
> > 5. Don't use bio_set_op_attrs and remove op and set
> > bi_opf directly
> > 6. Use struct_size to calculate total_size
> > 7. Fix partition remap of copy destination
> > 8. Remove mcl,mssrl,msrc from nvme_ns
> > 9. Initialize copy queue limits to 0 in nvme_config_copy
> > 10. Remove return in QUEUE_FLAG_COPY check
> > 11. Remove unused OCFS
> >
> > SelvaKumar S (4):
> > block: make bio_map_kern() non static
> > block: add simple copy support
> > nvme: add simple copy support
> > dm kcopyd: add simple copy offload support
> >
> > block/blk-core.c | 102 +++++++++++++++--
> > block/blk-lib.c | 223
> > ++++++++++++++++++++++++++++++++++++++
> > block/blk-map.c | 2 +-
> > block/blk-merge.c | 2 +
> > block/blk-settings.c | 10 ++
> > block/blk-sysfs.c | 47 ++++++++
> > block/blk-zoned.c | 1 +
> > block/bounce.c | 1 +
> > block/ioctl.c | 33 ++++++
> > drivers/md/dm-kcopyd.c | 49 ++++++++-
> > drivers/nvme/host/core.c | 87 +++++++++++++++
> > include/linux/bio.h | 1 +
> > include/linux/blk_types.h | 14 +++
> > include/linux/blkdev.h | 17 +++
> > include/linux/nvme.h | 43 +++++++-
> > include/uapi/linux/fs.h | 13 +++
> > 16 files changed, 627 insertions(+), 18 deletions(-)
>
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next prev parent reply other threads:[~2021-02-23 9:01 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210219124555epcas5p1334e7c4d64ada5dc4a2ca0feb48c1d44@epcas5p1.samsung.com>
2021-02-19 12:45 ` [RFC PATCH v5 0/4] add simple copy support SelvaKumar S
[not found] ` <CGME20210219124559epcas5p41da46f1c248e334953d407a154697903@epcas5p4.samsung.com>
2021-02-19 12:45 ` [RFC PATCH v5 1/4] block: make bio_map_kern() non static SelvaKumar S
[not found] ` <CGME20210219124603epcas5p33add0f2c1781b2a4d71bf30c9e1ac647@epcas5p3.samsung.com>
2021-02-19 12:45 ` [RFC PATCH v5 2/4] block: add simple copy support SelvaKumar S
2021-02-20 4:59 ` Damien Le Moal
2021-04-07 11:32 ` Selva Jove
2021-04-12 0:24 ` Damien Le Moal
2021-04-12 14:34 ` Selva Jove
2021-04-13 0:32 ` Damien Le Moal
2021-04-14 6:58 ` Selva Jove
[not found] ` <CGME20210219124608epcas5p2a673f9e00c3e7b5352f115497b0e2d98@epcas5p2.samsung.com>
2021-02-19 12:45 ` [RFC PATCH v5 3/4] nvme: " SelvaKumar S
2021-02-20 3:36 ` Matthew Wilcox
2021-02-22 15:57 ` Selva Jove
[not found] ` <CGME20210219124611epcas5p1c775b63b537e75da161556e375fcf05e@epcas5p1.samsung.com>
2021-02-19 12:45 ` [RFC PATCH v5 4/4] dm kcopyd: add simple copy offload support SelvaKumar S
2021-02-20 18:01 ` [RFC PATCH v5 0/4] add simple copy support David Laight
2021-02-20 19:08 ` Matthew Wilcox
2021-02-20 19:19 ` Keith Busch
2021-02-21 23:52 ` Dave Chinner
2021-02-23 9:14 ` Selva Jove
2021-02-22 1:31 ` Ming Lei
2021-02-22 6:52 ` Su Yue
2021-02-23 9:00 ` Selva Jove [this message]
2021-04-10 0:21 ` Max Gurtovoy
2021-04-10 0:29 ` Chaitanya Kulkarni
2021-04-10 6:32 ` Javier González
2021-04-11 9:10 ` Max Gurtovoy
2021-04-11 19:26 ` Javier González
2021-04-13 15:38 ` Max Gurtovoy
2021-04-13 18:25 ` Javier González
2021-04-13 18:36 ` Chaitanya Kulkarni
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