From: Linus Torvalds <torvalds@linux-foundation.org>
To: Roman Pen <roman.penyaev@profitbricks.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>,
linux-block <linux-block@vger.kernel.org>,
linux-rdma <linux-rdma@vger.kernel.org>,
Jens Axboe <axboe@kernel.dk>,
Christoph Hellwig <hch@infradead.org>,
Sagi Grimberg <sagi@grimberg.me>,
Bart Van Assche <bart.vanassche@sandisk.com>,
Or Gerlitz <ogerlitz@mellanox.com>,
Doug Ledford <dledford@redhat.com>,
swapnil.ingle@profitbricks.com, danil.kipnis@profitbricks.com,
jinpu.wang@profitbricks.com,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 01/26] rculist: introduce list_next_or_null_rr_rcu()
Date: Sat, 19 May 2018 13:56:45 -0700 [thread overview]
Message-ID: <CA+55aFwNByHq+OG5QmL4V2fXeduFHbTVOct6X0REHFRoLsrpdg@mail.gmail.com> (raw)
In-Reply-To: <CAJrWOzAt8BDtypaRwYx_y9jpCVD5W_VL9aQsFsC3bL-XaoJz9g@mail.gmail.com>
On Sat, May 19, 2018 at 1:21 PM Roman Penyaev <
roman.penyaev@profitbricks.com> wrote:
> I need -rr behaviour for doing IO load-balancing when I choose next RDMA
> connection from the list in order to send a request, i.e. my code is
> something like the following:
[ incomplete pseudoicode ]
> i.e. usage of the @next pointer is under an RCU critical section.
That's not enough. The whole chain to look up the pointer you are taking
'next' of needs to be under RCU, and that's not clear from your example.
It's *probably* the case, but basically you have to prove that the starting
point is still on the same RCU list. That wasn't clear from your example.
The above is (as Paul said) true of list_next_rcu() too, so it's not like
this is anything specific to the 'rr' version.
Linus
next prev parent reply other threads:[~2018-05-19 20:57 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180518130413.16997-1-roman.penyaev@profitbricks.com>
2018-05-18 13:03 ` [PATCH v2 01/26] rculist: introduce list_next_or_null_rr_rcu() Roman Pen
2018-05-18 16:56 ` Linus Torvalds
2018-05-19 20:25 ` Roman Penyaev
2018-05-19 21:04 ` Linus Torvalds
2018-05-19 16:37 ` Paul E. McKenney
2018-05-19 20:20 ` Roman Penyaev
2018-05-19 20:56 ` Linus Torvalds [this message]
2018-05-20 0:43 ` Paul E. McKenney
2018-05-21 13:50 ` Roman Penyaev
2018-05-21 15:16 ` Linus Torvalds
2018-05-21 15:33 ` Paul E. McKenney
2018-05-22 9:09 ` Roman Penyaev
2018-05-22 16:36 ` Paul E. McKenney
2018-05-22 16:38 ` Linus Torvalds
2018-05-22 17:04 ` Paul E. McKenney
2018-05-21 15:31 ` Paul E. McKenney
2018-05-22 9:09 ` Roman Penyaev
2018-05-22 17:03 ` Paul E. McKenney
2018-05-18 13:03 ` [PATCH v2 02/26] sysfs: export sysfs_remove_file_self() Roman Pen
2018-05-18 15:08 ` Tejun Heo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CA+55aFwNByHq+OG5QmL4V2fXeduFHbTVOct6X0REHFRoLsrpdg@mail.gmail.com \
--to=torvalds@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=bart.vanassche@sandisk.com \
--cc=danil.kipnis@profitbricks.com \
--cc=dledford@redhat.com \
--cc=hch@infradead.org \
--cc=jinpu.wang@profitbricks.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rdma@vger.kernel.org \
--cc=ogerlitz@mellanox.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=roman.penyaev@profitbricks.com \
--cc=sagi@grimberg.me \
--cc=swapnil.ingle@profitbricks.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).