linux-kernel - [PATCH v2 0/3] io_uring: avoid ring quiesce in io_uring

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]

Message-Id: <20220203164503.641574-1-usama.arif@bytedance.com>
Date:   Thu,  3 Feb 2022 16:45:00 +0000
From:   Usama Arif <usama.arif@...edance.com>
To:     io-uring@...r.kernel.org, axboe@...nel.dk, asml.silence@...il.com,
        linux-kernel@...r.kernel.org
Cc:     fam.zheng@...edance.com, Usama Arif <usama.arif@...edance.com>
Subject: [PATCH v2 0/3] io_uring: avoid ring quiesce in io_uring_register for eventfd opcodes

This is done by creating a new RCU data structure (io_ev_fd) as part of
io_ring_ctx that holds the eventfd_ctx, with reads to the structure protected
by rcu_read_lock and writes (register/unregister calls) protected by a mutex.

With the above approach ring quiesce can be avoided which is much more
expensive then using RCU lock. On the system tested, io_uring_reigster with
IORING_REGISTER_EVENTFD takes less than 1ms with RCU lock, compared to 15ms
before with ring quiesce.

The first patch creates the RCU protected data structure and removes ring
quiesce for IORING_REGISTER_EVENTFD and IORING_UNREGISTER_EVENTFD.

The second patch builds on top of the first patch and removes ring quiesce
for IORING_REGISTER_EVENTFD_ASYNC.

---
v1->v2:
- Added patch to remove eventfd from tracepoint (Patch 1) (Jens Axboe)
- Made the code of io_should_trigger_evfd as part of io_eventfd_signal (Jens Axboe)

Usama Arif (3):
  io_uring: remove trace for eventfd
  io_uring: avoid ring quiesce while registering/unregistering eventfd
  io_uring: avoid ring quiesce for IORING_REGISTER_EVENTFD_ASYNC

 fs/io_uring.c                   | 124 ++++++++++++++++++++++----------
 include/trace/events/io_uring.h |  13 ++--
 2 files changed, 93 insertions(+), 44 deletions(-)

-- 
2.25.1