From mboxrd@z Thu Jan 1 00:00:00 1970 From: Waiman Long Subject: [PATCH v7 0/3] blk-cgroup: Optimize blkcg_rstat_flush() Date: Mon, 3 Oct 2022 11:44:56 -0400 Message-ID: <20221003154459.207538-1-longman@redhat.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1664811932; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=xusHdmDukwYHMbUJFh7S0rrQ2RjmbWo7AAZhEr8dtGk=; b=PE/xP0G96LHSjfXtDyAR0gM+Ke4E8BmkXwBI06lt4nNcZINZsf3wHyFvXSVRPZQK2rI9WE HCSHarwyVFmp3mpLL8vxXVZ8HN5yh6/QJezE9AM7j2Jef/AdF/CCcR/dbt0uJuIV7ETq8T 5uP/8PHv6926jOtQuhzf8nvcm7jLLIE= List-ID: Content-Type: text/plain; charset="us-ascii" To: Tejun Heo , Jens Axboe Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-block-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ming Lei , Andy Shevchenko , Andrew Morton , Huang Ying , =?UTF-8?q?Michal=20Koutn=C3=BD?= , Waiman Long v7: - Drop patch 1 ("blk-cgroup: Correctly free percpu iostat_cpu in blkg on error exit") as it is found to be unnecessary. - Add a new llist patch to provide a lockless list variant terminated by a sentinel node. - Modified patch 3 to use the new sllist API and move percpu_ref_put() later in the blkcg_rstat_flush() loop to prevent potential use-after-free problem. v6: - Add a missing free_percpu() into blkcg_css_free() in patch 3. - Integrating the documentation patch 4 back into patch 3. v5: - Add a new patch 2 to eliminate the use of intermediate "ret" variable in blkcg_css_alloc() to fix compilation warning reported by kernel test robot. This patch series improves blkcg_rstat_flush() performance by eliminating unnecessary blkg enumeration and flush operations for those blkg's and blkg_iostat_set's that haven't been updated since the last flush. Waiman Long (3): llist: Add a lock-less list variant terminated by a sentinel node blk-cgroup: Return -ENOMEM directly in blkcg_css_alloc() error path blk-cgroup: Optimize blkcg_rstat_flush() block/blk-cgroup.c | 85 ++++++++++++++++++++++----- block/blk-cgroup.h | 9 +++ include/linux/llist.h | 132 +++++++++++++++++++++++++++++++++++++++++- lib/llist.c | 79 ++++++++++++++++++++++++- 4 files changed, 289 insertions(+), 16 deletions(-) -- 2.31.1