linux-kernel - [PATCH 0/2] xfs: Use wake_q for waking up log space waiters

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Thu, 23 Aug 2018 12:26:08 -0400
From:   Waiman Long <longman@...hat.com>
To:     "Darrick J. Wong" <darrick.wong@...cle.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     linux-xfs@...r.kernel.org, linux-kernel@...r.kernel.org,
        Dave Chinner <dchinner@...hat.com>,
        Waiman Long <longman@...hat.com>
Subject: [PATCH 0/2] xfs: Use wake_q for waking up log space waiters

While running the AIM7 microbenchmark, it was found that there was
a severe spinlock contention problem in the current XFS log space
reservation code. To alleviate the problem, the log space waiter
waiting and waking functions are modified to use the wake_q for waking
up waiters without holding the lock so as to reduce the lock hold time.

The result was a 4X performance improvement in that microbenchmark
which is worth persuing.

Patch 1 is an enablement patch to make wake_q service available to
kernel modules.

Patch 2 changes the XFS log space reservation code to use wake_q for
task wakeup.

Waiman Long (2):
  sched/core: Export wake_q functions to kernel modules
  xfs: Use wake_q for waking up log space waiters

 fs/xfs/xfs_log.c             | 48 ++++++++++++++++++++++++++++++++++----------
 include/linux/sched/wake_q.h |  5 +++++
 kernel/sched/core.c          |  2 ++
 3 files changed, 44 insertions(+), 11 deletions(-)

-- 
1.8.3.1