From: Peter Zijlstra <peterz@infradead.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: linux-kernel@vger.kernel.org, torvalds@linux-foundation.org,
manfred@colorfullife.com, dave@stgolabs.net,
paulmck@linux.vnet.ibm.com, will.deacon@arm.com,
Waiman.Long@hpe.com, tj@kernel.org, pablo@netfilter.org,
kaber@trash.net, davem@davemloft.net, oleg@redhat.com,
netfilter-devel@vger.kernel.org, sasha.levin@oracle.com,
hofrat@osadl.org, jejb@parisc-linux.org, chris@zankel.net,
rth@twiddle.net, dhowells@redhat.com, schwidefsky@de.ibm.com,
mpe@ellerman.id.au, ralf@linux-mips.org, linux@armlinux.org.uk,
rkuo@codeaurora.org, vgupta@synopsys.com, james.hogan@imgtec.com,
realmz6@gmail.com, ysato@users.sourceforge.jp,
tony.luck@intel.com, cmetcalf@mellanox.com
Subject: Re: [PATCH -v4 5/7] locking, arch: Update spin_unlock_wait()
Date: Thu, 2 Jun 2016 16:44:24 +0200 [thread overview]
Message-ID: <20160602144424.GV3193@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20160602142440.GE30064@insomnia>
On Thu, Jun 02, 2016 at 10:24:40PM +0800, Boqun Feng wrote:
> On Thu, Jun 02, 2016 at 01:52:02PM +0200, Peter Zijlstra wrote:
> About spin_unlock_wait() on ppc, I actually have a fix pending review:
>
> http://lkml.kernel.org/r/1461130033-70898-1-git-send-email-boqun.feng@gmail.com
Please use the normal commit quoting style:
d86b8da04dfa ("arm64: spinlock: serialise spin_unlock_wait against concurrent lockers")
> that patch fixed a different problem when people want to pair a
> spin_unlock_wait() with a spin_lock().
Argh, indeed, and I think qspinlock is still broken there :/ But my poor
brain is about to give in for the day.
Let me go ponder that some :/
> I think we still need that fix, and there are two conflicts with this
> series:
>
> 1. arch_spin_unlock_wait() code for PPC32 was deleted, and
> consolidated into one.
Nice.
> 2. I actually downgraded spin_unlock_wait() to !ACQUIRE ;-)
Fail ;-)
> I can think of two ways to solve thoes conflicts:
>
> 1. Modify my patch to make spin_unlock_wait() an ACQUIRE, and it
> can be merged in powerpc tree, and possible go into to mainline
> before 4.7. Then there is no need for this series to have code
> for ppc, therefore no conflict.
Hardly any other unlock_wait is an acquire, everyone is 'broken' :-/
> or
>
> 2. I can rebase my patch on this series, and it can be added in
> this series, and will go into mainline at 4.8.
>
>
> Michael and Peter, any thought?
I'm fine with it going in early, I can rebase, no problem.
next prev parent reply other threads:[~2016-06-02 14:45 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-02 11:51 [PATCH -v4 0/7] spin_unlock_wait borkage and assorted bits Peter Zijlstra
2016-06-02 11:51 ` [PATCH -v4 1/7] locking: Replace smp_cond_acquire with smp_cond_load_acquire Peter Zijlstra
2016-06-02 11:51 ` [PATCH -v4 2/7] locking: Introduce smp_acquire__after_ctrl_dep Peter Zijlstra
2016-06-02 11:52 ` [PATCH -v4 3/7] locking: Move smp_cond_load_acquire() to asm-generic/barrier.h Peter Zijlstra
2016-06-02 11:52 ` [PATCH -v4 4/7] locking, tile: Provide TILE specific smp_acquire__after_ctrl_dep Peter Zijlstra
2016-06-02 11:52 ` [PATCH -v4 5/7] locking, arch: Update spin_unlock_wait() Peter Zijlstra
2016-06-02 14:24 ` Boqun Feng
2016-06-02 14:44 ` Peter Zijlstra [this message]
2016-06-02 15:11 ` Boqun Feng
2016-06-02 15:57 ` Boqun Feng
2016-06-02 16:04 ` Peter Zijlstra
2016-06-02 16:34 ` Peter Zijlstra
2016-06-02 17:57 ` Will Deacon
2016-06-02 21:51 ` Peter Zijlstra
2016-06-03 12:47 ` Will Deacon
2016-06-03 13:42 ` Peter Zijlstra
2016-06-03 17:35 ` Will Deacon
2016-06-03 19:13 ` Peter Zijlstra
2016-06-03 13:48 ` Peter Zijlstra
2016-06-06 16:08 ` Peter Zijlstra
2016-06-07 11:43 ` Boqun Feng
2016-06-07 12:00 ` Peter Zijlstra
2016-06-07 12:45 ` Boqun Feng
2016-06-07 17:36 ` Peter Zijlstra
2016-06-02 11:52 ` [PATCH -v4 6/7] locking: Update spin_unlock_wait users Peter Zijlstra
2016-06-02 11:52 ` [PATCH -v4 7/7] locking,netfilter: Fix nf_conntrack_lock() Peter Zijlstra
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