From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: paulmck@linux.vnet.ibm.com, tj@kernel.org, mingo@redhat.com,
linux-kernel@vger.kernel.org, der.herr@hofr.at,
dave@stgolabs.net, riel@redhat.com, viro@ZenIV.linux.org.uk,
torvalds@linux-foundation.org
Subject: [PATCH 0/3] percpu-rwsem: introduce percpu_rw_semaphore->recursive mode
Date: Mon, 29 Jun 2015 01:56:14 +0200 [thread overview]
Message-ID: <20150628235614.GA24454@redhat.com> (raw)
In-Reply-To: <20150624135049.GA31992@redhat.com>
On 06/24, Oleg Nesterov wrote:
>
> So we need percpu_down_write_dont_block_readers(). I already thought
> about this before, I'll try to make the patch tomorrow on top of your
> changes.
Never say tomorrow...
> This means that we do not need task_struct->cpuhp_ref, but we can't
> avoid livelock we currently have: cpu_hotplug_begin() can never succeed
> if the new readers come fast enough.
Like with any other "recursive" lock.
Peter, I know you don't like the 1st patch. And yes, we could add another
mutex into percpu_rw_semaphore instead. But I think it would be better
to rely on rcu_sync_enter(). As for completion, we can remove it later.
Nevermind, the actual change is 3/3 and it looks simple.
Oleg.
next prev parent reply other threads:[~2015-06-28 23:57 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-22 12:16 [RFC][PATCH 00/13] percpu rwsem -v2 Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 01/13] rcu: Create rcu_sync infrastructure Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 02/13] rcusync: Introduce struct rcu_sync_ops Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 03/13] rcusync: Add the CONFIG_PROVE_RCU checks Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 04/13] rcusync: Introduce rcu_sync_dtor() Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 05/13] percpu-rwsem: Optimize readers and reduce global impact Peter Zijlstra
2015-06-22 23:02 ` Oleg Nesterov
2015-06-23 7:28 ` Nicholas Mc Guire
2015-06-25 19:08 ` Peter Zijlstra
2015-06-25 19:17 ` Tejun Heo
2015-06-29 9:32 ` Peter Zijlstra
2015-06-29 15:12 ` Tejun Heo
2015-06-29 15:14 ` Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 06/13] percpu-rwsem: Provide percpu_down_read_trylock() Peter Zijlstra
2015-06-22 23:08 ` Oleg Nesterov
2015-06-22 12:16 ` [RFC][PATCH 07/13] sched: Reorder task_struct Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 08/13] percpu-rwsem: DEFINE_STATIC_PERCPU_RWSEM Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 09/13] hotplug: Replace hotplug lock with percpu-rwsem Peter Zijlstra
2015-06-22 22:57 ` Oleg Nesterov
2015-06-23 7:16 ` Peter Zijlstra
2015-06-23 17:01 ` Oleg Nesterov
2015-06-23 17:53 ` Peter Zijlstra
2015-06-24 13:50 ` Oleg Nesterov
2015-06-24 14:13 ` Peter Zijlstra
2015-06-24 15:12 ` Oleg Nesterov
2015-06-24 16:15 ` Peter Zijlstra
2015-06-28 23:56 ` Oleg Nesterov [this message]
2015-06-28 23:56 ` [PATCH 1/3] rcusync: introduce rcu_sync_struct->exclusive mode Oleg Nesterov
2015-06-28 23:56 ` [PATCH 2/3] percpu-rwsem: don't use percpu_rw_semaphore->rw_sem to exclude writers Oleg Nesterov
2015-06-28 23:56 ` [PATCH 3/3] percpu-rwsem: introduce percpu_rw_semaphore->recursive mode Oleg Nesterov
2015-06-22 12:16 ` [RFC][PATCH 10/13] fs/locks: Replace lg_global with a percpu-rwsem Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 11/13] fs/locks: Replace lg_local with a per-cpu spinlock Peter Zijlstra
2015-06-23 0:19 ` Oleg Nesterov
2015-06-22 12:16 ` [RFC][PATCH 12/13] stop_machine: Remove lglock Peter Zijlstra
2015-06-22 22:21 ` Oleg Nesterov
2015-06-23 10:09 ` Peter Zijlstra
2015-06-23 10:55 ` Peter Zijlstra
2015-06-23 11:20 ` Peter Zijlstra
2015-06-23 13:08 ` Peter Zijlstra
2015-06-23 16:36 ` Oleg Nesterov
2015-06-23 17:30 ` Paul E. McKenney
2015-06-23 18:04 ` Peter Zijlstra
2015-06-23 18:26 ` Paul E. McKenney
2015-06-23 19:05 ` Paul E. McKenney
2015-06-24 2:23 ` Paul E. McKenney
2015-06-24 8:32 ` Peter Zijlstra
2015-06-24 9:31 ` Peter Zijlstra
2015-06-24 13:48 ` Paul E. McKenney
2015-06-24 15:01 ` Paul E. McKenney
2015-06-24 15:34 ` Peter Zijlstra
2015-06-24 7:35 ` Peter Zijlstra
2015-06-24 8:42 ` Ingo Molnar
2015-06-24 13:39 ` Paul E. McKenney
2015-06-24 13:43 ` Ingo Molnar
2015-06-24 14:03 ` Paul E. McKenney
2015-06-24 14:50 ` Paul E. McKenney
2015-06-24 15:01 ` Peter Zijlstra
2015-06-24 15:27 ` Paul E. McKenney
2015-06-24 15:40 ` Peter Zijlstra
2015-06-24 16:09 ` Paul E. McKenney
2015-06-24 16:42 ` Peter Zijlstra
2015-06-24 17:10 ` Paul E. McKenney
2015-06-24 17:20 ` Paul E. McKenney
2015-06-24 17:29 ` Peter Zijlstra
2015-06-24 17:28 ` Peter Zijlstra
2015-06-24 17:32 ` Peter Zijlstra
2015-06-24 18:14 ` Peter Zijlstra
2015-06-24 17:58 ` Peter Zijlstra
2015-06-25 3:23 ` Paul E. McKenney
2015-06-25 11:07 ` Peter Zijlstra
2015-06-25 13:47 ` Paul E. McKenney
2015-06-25 14:20 ` Peter Zijlstra
2015-06-25 14:51 ` Paul E. McKenney
2015-06-26 12:32 ` Peter Zijlstra
2015-06-26 16:14 ` Paul E. McKenney
2015-06-29 7:56 ` Peter Zijlstra
2015-06-30 21:32 ` Paul E. McKenney
2015-07-01 11:56 ` Peter Zijlstra
2015-07-01 15:56 ` Paul E. McKenney
2015-07-01 16:16 ` Peter Zijlstra
2015-07-01 18:45 ` Paul E. McKenney
2015-06-23 14:39 ` Paul E. McKenney
2015-06-23 16:20 ` Oleg Nesterov
2015-06-23 17:24 ` Oleg Nesterov
2015-06-25 19:18 ` Peter Zijlstra
2015-06-22 12:16 ` [RFC][PATCH 13/13] locking: " Peter Zijlstra
2015-06-22 12:36 ` [RFC][PATCH 00/13] percpu rwsem -v2 Peter Zijlstra
2015-06-22 18:11 ` Daniel Wagner
2015-06-22 19:05 ` Peter Zijlstra
2015-06-23 9:35 ` Daniel Wagner
2015-06-23 10:00 ` Ingo Molnar
2015-06-23 14:34 ` Peter Zijlstra
2015-06-23 14:56 ` Daniel Wagner
2015-06-23 17:50 ` Peter Zijlstra
2015-06-23 19:36 ` Peter Zijlstra
2015-06-24 8:46 ` Ingo Molnar
2015-06-24 9:01 ` Peter Zijlstra
2015-06-24 9:18 ` Daniel Wagner
2015-07-01 5:57 ` Daniel Wagner
2015-07-01 21:54 ` Linus Torvalds
2015-07-02 9:41 ` Peter Zijlstra
2015-07-20 5:53 ` Daniel Wagner
2015-07-20 18:44 ` Linus Torvalds
2015-06-22 20:06 ` Linus Torvalds
2015-06-23 16:10 ` Davidlohr Bueso
2015-06-23 16:21 ` Peter Zijlstra
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=20150628235614.GA24454@redhat.com \
--to=oleg@redhat.com \
--cc=dave@stgolabs.net \
--cc=der.herr@hofr.at \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--cc=tj@kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=viro@ZenIV.linux.org.uk \
/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).