From: Ming Lei <ming.lei@redhat.com>
To: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Cc: Ming Lei <ming.lei@redhat.com>,
Veronika Kabatova <vkabatov@redhat.com>,
Sagi Grimberg <sagi@grimberg.me>, Tejun Heo <tj@kernel.org>,
Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
Bart Van Assche <bvanassche@acm.org>
Subject: [PATCH V5 0/3] percpu_ref & block: reduce memory footprint of percpu_ref in fast path
Date: Sun, 27 Sep 2020 14:26:51 +0800 [thread overview]
Message-ID: <20200927062654.2750277-1-ming.lei@redhat.com> (raw)
Hi,
The 1st patch removes memory footprint of percpu_ref in fast path
from 7 words to 2 words, since it is often used in fast path and
embedded in user struct.
The 2nd patch moves .q_usage_counter to 1st cacheline of
'request_queue'.
Simple test on null_blk shows ~2% IOPS boost on one 16cores(two threads
per core) machine, dual socket/numa.
V5:
- fix memory leak on ref->data, only percpu_ref_exit() of patch 2
is modified.
V4:
- rename percpu_ref_inited as percpu_ref_is_initialized
V3:
- fix kernel oops on MD
- add patch for avoiding to use percpu-refcount internal from md
code
- pass Red Hat CKI test which is done by Veronika Kabatova
V2:
- pass 'gfp' to kzalloc() for fixing block/027 failure reported by
kernel test robot
- protect percpu_ref_is_zero() with destroying percpu-refcount by
spin lock
Ming Lei (3):
percpu_ref: add percpu_ref_is_initialized for MD
percpu_ref: reduce memory footprint of percpu_ref in fast path
block: move 'q_usage_counter' into front of 'request_queue'
drivers/infiniband/sw/rdmavt/mr.c | 2 +-
drivers/md/md.c | 2 +-
include/linux/blkdev.h | 3 +-
include/linux/percpu-refcount.h | 46 ++++------
lib/percpu-refcount.c | 137 +++++++++++++++++++++++-------
5 files changed, 126 insertions(+), 64 deletions(-)
Cc: Veronika Kabatova <vkabatov@redhat.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Bart Van Assche <bvanassche@acm.org>
--
2.25.2
next reply other threads:[~2020-09-27 6:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-27 6:26 Ming Lei [this message]
2020-09-27 6:26 ` [PATCH V5 1/3] percpu_ref: add percpu_ref_is_initialized for MD Ming Lei
2020-09-28 7:30 ` Christoph Hellwig
2020-09-27 6:26 ` [PATCH V5 2/3] percpu_ref: reduce memory footprint of percpu_ref in fast path Ming Lei
2020-09-27 6:26 ` [PATCH V5 3/3] block: move 'q_usage_counter' into front of 'request_queue' Ming Lei
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