From: John Garry <john.garry@huawei.com>
To: <axboe@kernel.dk>
Cc: <linux-block@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<ming.lei@redhat.com>, <linux-scsi@vger.kernel.org>,
John Garry <john.garry@huawei.com>
Subject: [PATCH v3 00/13] blk-mq: Reduce static requests memory footprint for shared sbitmap
Date: Fri, 27 Aug 2021 20:01:51 +0800 [thread overview]
Message-ID: <1630065724-69146-1-git-send-email-john.garry@huawei.com> (raw)
Currently a full set of static requests are allocated per hw queue per
tagset when shared sbitmap is used.
However, only tagset->queue_depth number of requests may be active at
any given time. As such, only tagset->queue_depth number of static
requests are required.
The same goes for using an IO scheduler, which allocates a full set of
static requests per hw queue per request queue.
This series changes shared sbitmap support by using a shared tags per
tagset and request queue. Ming suggested something along those lines in
v1 review. But we'll keep name "shared sbitmap" name as it is familiar. In
using a shared tags, the static rqs also become shared, reducing the
number of sets of static rqs, reducing memory usage.
Patch "blk-mq: Use shared tags for shared sbitmap support" is a bit big,
and could potentially be broken down. But then maintaining ability to
bisect becomes harder and each sub-patch would get more convoluted.
For megaraid sas driver on my 128-CPU arm64 system with 1x SATA disk, we
save approx. 300MB(!) [370MB -> 60MB]
Baseline is 1d1cf156dc17 (block/for-5.15/block) sg: pass the device...
Changes since v2:
- Make blk_mq_clear_rq_mapping() static again
- Various function renaming for conciseness and consistency
- Add/refactor alloc/free map and rqs function
- Drop the new blk_mq_ops init_request method in favour of passing an
invalid HW queue index for shared sbitmap
- Add patch to not clear rq mapping for driver tags
- Remove blk_mq_init_bitmap_tags()
- Add some more RB tags (thanks!)
Changes since v1:
- Switch to use blk_mq_tags for shared sbitmap
- Add new blk_mq_ops init request callback
- Add some RB tags (thanks!)
John Garry (13):
blk-mq: Change rqs check in blk_mq_free_rqs()
block: Rename BLKDEV_MAX_RQ -> BLKDEV_DEFAULT_RQ
blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests()
blk-mq: Invert check in blk_mq_update_nr_requests()
blk-mq-sched: Rename blk_mq_sched_alloc_{tags -> map_and_rqs}()
blk-mq-sched: Rename blk_mq_sched_free_{requests -> rqs}()
blk-mq: Pass driver tags to blk_mq_clear_rq_mapping()
blk-mq: Don't clear driver tags own mapping
blk-mq: Add blk_mq_tag_update_sched_shared_sbitmap()
blk-mq: Add blk_mq_alloc_map_and_rqs()
blk-mq: Refactor and rename blk_mq_free_map_and_{requests->rqs}()
blk-mq: Use shared tags for shared sbitmap support
blk-mq: Stop using pointers for blk_mq_tags bitmap tags
block/bfq-iosched.c | 4 +-
block/blk-core.c | 4 +-
block/blk-mq-debugfs.c | 8 +-
block/blk-mq-sched.c | 116 ++++++++++------------
block/blk-mq-sched.h | 4 +-
block/blk-mq-tag.c | 125 ++++++++---------------
block/blk-mq-tag.h | 14 +--
block/blk-mq.c | 209 +++++++++++++++++++++++----------------
block/blk-mq.h | 18 ++--
block/blk.h | 2 +-
block/kyber-iosched.c | 4 +-
block/mq-deadline-main.c | 2 +-
drivers/block/rbd.c | 2 +-
include/linux/blk-mq.h | 15 ++-
include/linux/blkdev.h | 5 +-
15 files changed, 256 insertions(+), 276 deletions(-)
--
2.26.2
next reply other threads:[~2021-08-27 12:06 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-27 12:01 John Garry [this message]
2021-08-27 12:01 ` [PATCH v3 01/13] blk-mq: Change rqs check in blk_mq_free_rqs() John Garry
2021-08-27 12:01 ` [PATCH v3 02/13] block: Rename BLKDEV_MAX_RQ -> BLKDEV_DEFAULT_RQ John Garry
2021-08-27 12:01 ` [PATCH v3 03/13] blk-mq: Relocate shared sbitmap resize in blk_mq_update_nr_requests() John Garry
2021-08-27 12:01 ` [PATCH v3 04/13] blk-mq: Invert check " John Garry
2021-08-27 12:01 ` [PATCH v3 05/13] blk-mq-sched: Rename blk_mq_sched_alloc_{tags -> map_and_rqs}() John Garry
2021-08-27 12:01 ` [PATCH v3 06/13] blk-mq-sched: Rename blk_mq_sched_free_{requests -> rqs}() John Garry
2021-08-27 12:01 ` [PATCH v3 07/13] blk-mq: Pass driver tags to blk_mq_clear_rq_mapping() John Garry
2021-08-27 12:01 ` [PATCH v3 08/13] blk-mq: Don't clear driver tags own mapping John Garry
2021-08-27 12:02 ` [PATCH v3 09/13] blk-mq: Add blk_mq_tag_update_sched_shared_sbitmap() John Garry
2021-08-27 12:02 ` [PATCH v3 10/13] blk-mq: Add blk_mq_alloc_map_and_rqs() John Garry
2021-08-27 12:02 ` [PATCH v3 11/13] blk-mq: Refactor and rename blk_mq_free_map_and_{requests->rqs}() John Garry
2021-08-27 12:02 ` [PATCH v3 12/13] blk-mq: Use shared tags for shared sbitmap support John Garry
2021-08-27 12:02 ` [PATCH v3 13/13] blk-mq: Stop using pointers for blk_mq_tags bitmap tags John Garry
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