From: Joel Fernandes <joel@joelfernandes•org>
To: "Paul E. McKenney" <paulmck@linux•ibm.com>
Cc: linux-kernel@vger•kernel.org,
Alexey Kuznetsov <kuznet@ms2•inr.ac.ru>,
Bjorn Helgaas <bhelgaas@google•com>,
Borislav Petkov <bp@alien8•de>,
c0d1n61at3@gmail•com, "David S. Miller" <davem@davemloft•net>,
edumazet@google•com,
Greg Kroah-Hartman <gregkh@linuxfoundation•org>,
Hideaki YOSHIFUJI <yoshfuji@linux-ipv6•org>,
"H. Peter Anvin" <hpa@zytor•com>, Ingo Molnar <mingo@redhat•com>,
Jonathan Corbet <corbet@lwn•net>,
Josh Triplett <josh@joshtriplett•org>,
keescook@chromium•org, kernel-hardening@lists•openwall.com,
kernel-team@android•com, Lai Jiangshan <jiangshanlai@gmail•com>,
Len Brown <lenb@kernel•org>,
linux-acpi@vger•kernel.org, linux-doc@vger•kernel.org,
linux-pci@vger•kernel.org, linux-pm@vger•kernel.org,
Mathieu Desnoyers <mathieu.desnoyers@efficios•com>,
neilb@suse•com, netdev@vger•kernel.org,
Oleg Nesterov <oleg@redhat•com>, Pavel Machek <pavel@ucw•cz>,
peterz@infradead•org, "Rafael J. Wysocki" <rjw@rjwysocki•net>,
Rasmus Villemoes <rasmus.villemoes@prevas•dk>,
rcu@vger•kernel.org, Steven Rostedt <rostedt@goodmis•org>,
Tejun Heo <tj@kernel•org>, Thomas Gleixner <tglx@linutronix•de>,
will@kernel•org,
"maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
<x86@kernel•org>
Subject: Re: [PATCH 2/9] rcu: Add support for consolidated-RCU reader checking (v3)
Date: Tue, 16 Jul 2019 18:02:05 -0400 [thread overview]
Message-ID: <20190716220205.GB172157@google.com> (raw)
In-Reply-To: <20190716185303.GM14271@linux.ibm.com>
On Tue, Jul 16, 2019 at 11:53:03AM -0700, Paul E. McKenney wrote:
[snip]
> > > A few more things below.
> > > > ---
> > > > include/linux/rculist.h | 28 ++++++++++++++++++++-----
> > > > include/linux/rcupdate.h | 7 +++++++
> > > > kernel/rcu/Kconfig.debug | 11 ++++++++++
> > > > kernel/rcu/update.c | 44 ++++++++++++++++++++++++----------------
> > > > 4 files changed, 67 insertions(+), 23 deletions(-)
> > > >
> > > > diff --git a/include/linux/rculist.h b/include/linux/rculist.h
> > > > index e91ec9ddcd30..1048160625bb 100644
> > > > --- a/include/linux/rculist.h
> > > > +++ b/include/linux/rculist.h
> > > > @@ -40,6 +40,20 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
> > > > */
> > > > #define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next)))
> > > >
> > > > +/*
> > > > + * Check during list traversal that we are within an RCU reader
> > > > + */
> > > > +
> > > > +#ifdef CONFIG_PROVE_RCU_LIST
> > >
> > > This new Kconfig option is OK temporarily, but unless there is reason to
> > > fear malfunction that a few weeks of rcutorture, 0day, and -next won't
> > > find, it would be better to just use CONFIG_PROVE_RCU. The overall goal
> > > is to reduce the number of RCU knobs rather than grow them, must though
> > > history might lead one to believe otherwise. :-/
> >
> > If you want, we can try to drop this option and just use PROVE_RCU however I
> > must say there may be several warnings that need to be fixed in a short
> > period of time (even a few weeks may be too short) considering the 1000+
> > uses of RCU lists.
> Do many people other than me build with CONFIG_PROVE_RCU? If so, then
> that would be a good reason for a temporary CONFIG_PROVE_RCU_LIST,
> as in going away in a release or two once the warnings get fixed.
PROVE_RCU is enabled by default with PROVE_LOCKING, so it is used quite
heavilty.
> > But I don't mind dropping it and it may just accelerate the fixing up of all
> > callers.
>
> I will let you decide based on the above question. But if you have
> CONFIG_PROVE_RCU_LIST, as noted below, it needs to depend on RCU_EXPERT.
Ok, will make it depend. But yes for temporary purpose, I will leave it as a
config and remove it later.
thanks,
- Joel
next prev parent reply other threads:[~2019-07-16 22:02 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-15 14:36 [PATCH 0/9] Harden list_for_each_entry_rcu() and family Joel Fernandes (Google)
2019-07-15 14:36 ` [PATCH 1/9] rcu/update: Remove useless check for debug_locks (v1) Joel Fernandes (Google)
2019-07-15 14:36 ` [PATCH 2/9] rcu: Add support for consolidated-RCU reader checking (v3) Joel Fernandes (Google)
2019-07-16 18:38 ` Paul E. McKenney
2019-07-16 18:46 ` Joel Fernandes
2019-07-16 18:53 ` Paul E. McKenney
2019-07-16 22:02 ` Joel Fernandes [this message]
2019-07-17 0:07 ` Paul E. McKenney
2019-07-15 14:36 ` [PATCH 3/9] rcu/sync: Remove custom check for reader-section (v2) Joel Fernandes (Google)
2019-07-16 18:39 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 4/9] ipv4: add lockdep condition to fix for_each_entry (v1) Joel Fernandes (Google)
2019-07-16 18:39 ` Paul E. McKenney
2019-07-16 21:12 ` David Miller
2019-07-15 14:37 ` [PATCH 5/9] driver/core: Convert to use built-in RCU list checking (v1) Joel Fernandes (Google)
2019-07-16 18:40 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 6/9] workqueue: Convert for_each_wq to use built-in list check (v2) Joel Fernandes (Google)
2019-07-16 18:41 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 7/9] x86/pci: Pass lockdep condition to pcm_mmcfg_list iterator (v1) Joel Fernandes (Google)
2019-07-15 20:02 ` Bjorn Helgaas
2019-07-16 4:03 ` Joel Fernandes
2019-07-16 18:42 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 8/9] acpi: Use built-in RCU list checking for acpi_ioremaps list (v1) Joel Fernandes (Google)
2019-07-15 21:44 ` Rafael J. Wysocki
2019-07-16 18:43 ` Paul E. McKenney
2019-07-15 14:37 ` [PATCH 9/9] doc: Update documentation about list_for_each_entry_rcu (v1) Joel Fernandes (Google)
2019-07-16 18:46 ` [PATCH 0/9] Harden list_for_each_entry_rcu() and family Paul E. McKenney
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