From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCHSET v2 block/for-next] blk-cgroup: use cgroup rstat for IO stats Date: Thu, 7 Nov 2019 11:17:58 -0800 Message-ID: <20191107191804.3735303-1-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id; bh=frzwKB0VNTg+ZAOVk2Hg0rgtTZGxKwYo7SANV2FiQrw=; b=DOtNb0bgjksnLw/UHH2dC6pOHZ3neE0l5WG9BV60l4/UEztqwQIh3Pg8wei/4bfnwG 1/koANBb+xnwdqepckcyRxW7EZbM1yYcB8bDFXHcxqFGBFYWR4iU+WMfrZsOjMZ+fwUV OUQIKOMoSdOOKaQYk8ot8vA+0aUqFHFToNT8yYqqBZSlq8IM3+umU2obkvdeVAng5xlX d6VDCaVrc0TglUoj9RlpIRwN3JxRIGuABtOGAsznBkXRJGz8J99LsmyaCK7octLWtch0 ek+3emCiEQ6KPfRl3yVPqP8Js3Dhuz2LsjHUZf0tb8wnTgzoAyAYxH8Hh9oZnmqEd8Je H2eQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: axboe@kernel.dk Cc: cgroups@vger.kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, lizefan@huawei.com, hannes@cmpxchg.org, kernel-team@fb.com Hello, v2: Build fix when !DEBUG. blk-cgroup IO stats currently use blkg_rwstat which unforutnately requires walking all descendants recursively on read. On systems with a large number of cgroups (dead or alive), this can make each stat read a substantially expensive operation. This patch updates blk-cgroup to use cgroup rstat which makes stat reading O(# descendants which have been active since last reading) instead of O(# descendants). 0001-bfq-iosched-relocate-bfqg_-rwstat-helpers.patch 0002-bfq-iosched-stop-using-blkg-stat_bytes-and-stat_ios.patch 0003-blk-throtl-stop-using-blkg-stat_bytes-and-stat_ios.patch 0004-blk-cgroup-remove-now-unused-blkg_print_stat_-bytes-.patch 0005-blk-cgroup-reimplement-basic-IO-stats-using-cgroup-r.patch 0006-blk-cgroup-separate-out-blkg_rwstat-under-CONFIG_BLK.patch 0001-0003 make bfq-iosched and blk-throtl use their own blkg_rwstat to track basic IO stats on cgroup1 instead of sharing blk-cgroup core's. 0004 is a follow-up cleanup. 0005 switches blk-cgroup to cgroup rstat. 0006 moves blkg_rwstat to its own files and gate it under a config option as it's now only used by blk-throtl and bfq-iosched. The patchset is on top of block/for-next 40afbe18b03a ("Merge branch 'for-5.5/drivers-post' into for-next") + block/for-linus b0814361a25c ("blkcg: make blkcg_print_stat() print stats only for online blkgs") and also available in the following git branch. git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-blkcg-rstat Thanks. block/Kconfig | 4 block/Kconfig.iosched | 1 block/Makefile | 1 block/bfq-cgroup.c | 37 +++-- block/bfq-iosched.c | 4 block/bfq-iosched.h | 6 block/blk-cgroup-rwstat.c | 129 +++++++++++++++++++ block/blk-cgroup-rwstat.h | 149 ++++++++++++++++++++++ block/blk-cgroup.c | 304 ++++++++++++++------------------------------- block/blk-throttle.c | 71 +++++++++- include/linux/blk-cgroup.h | 198 +++++------------------------ 11 files changed, 517 insertions(+), 387 deletions(-) -- tejun [1] http://lkml.kernel.org/r/20191105160951.GS3622521@devbig004.ftw2.facebook.com