From: Peter Zijlstra <peterz@infradead.org>
To: Michal Simek <michal.simek@xilinx.com>
Cc: linux-kernel@vger.kernel.org, monstr@monstr.eu, git@xilinx.com,
arnd@arndb.de, Stefan Asserhall <stefan.asserhall@xilinx.com>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>
Subject: Re: [PATCH 6/7] microblaze: Implement architecture spinlock
Date: Thu, 13 Feb 2020 09:00:43 +0100 [thread overview]
Message-ID: <20200213080043.GF14897@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <5315513c-2492-6bb7-2961-b249851b2051@xilinx.com>
On Thu, Feb 13, 2020 at 08:51:38AM +0100, Michal Simek wrote:
> On 12. 02. 20 16:47, Peter Zijlstra wrote:
> >
> > That's a test-and-set spinlock if I read it correctly. Why? that's the
> > worst possible spinlock implementation possible.
>
> This was written by Stefan and it is aligned with recommended
> implementation. What other options do we have?
A ticket lock should be simple enough; ARM has one you can borrow from.
The problem with TaS spinlocks is that they're unfair and exhibit
horrible starvation issues.
next prev parent reply other threads:[~2020-02-13 8:00 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 15:42 [PATCH 0/7] microblaze: Define SMP safe operations Michal Simek
2020-02-12 15:42 ` [PATCH 1/7] microblaze: timer: Don't use cpu timer setting Michal Simek
2020-02-12 15:42 ` [PATCH 2/7] microblaze: Make cpuinfo structure SMP aware Michal Simek
2020-02-12 20:42 ` Arnd Bergmann
2020-02-12 15:42 ` [PATCH 3/7] microblaze: Define SMP safe bit operations Michal Simek
2020-02-12 15:53 ` Peter Zijlstra
2020-02-13 8:42 ` Michal Simek
2020-02-13 9:01 ` Stefan Asserhall
2020-02-13 9:11 ` Peter Zijlstra
2020-02-13 9:24 ` Stefan Asserhall
2020-02-12 15:42 ` [PATCH 4/7] microblaze: Add SMP implementation of xchg and cmpxchg Michal Simek
2020-02-12 15:42 ` [PATCH 5/7] microblaze: Remove disabling IRQ while pte_update() run Michal Simek
2020-02-12 15:42 ` [PATCH 6/7] microblaze: Implement architecture spinlock Michal Simek
2020-02-12 15:47 ` Peter Zijlstra
2020-02-13 7:51 ` Michal Simek
2020-02-13 8:00 ` Peter Zijlstra [this message]
2020-02-12 15:42 ` [PATCH 7/7] microblaze: Do atomic operations by using exclusive ops Michal Simek
2020-02-12 15:55 ` Peter Zijlstra
2020-02-13 8:06 ` Michal Simek
2020-02-13 8:58 ` Peter Zijlstra
2020-02-13 9:16 ` Peter Zijlstra
2020-02-13 10:04 ` Will Deacon
2020-02-13 10:14 ` Stefan Asserhall
2020-02-13 10:20 ` Will Deacon
2020-02-13 10:15 ` Peter Zijlstra
2020-02-13 11:34 ` Boqun Feng
2020-02-13 11:38 ` Boqun Feng
2020-02-13 13:51 ` Andrea Parri
2020-02-13 14:01 ` Andrea Parri
2020-02-12 16:08 ` [PATCH 0/7] microblaze: Define SMP safe operations Peter Zijlstra
2020-02-12 16:38 ` Peter Zijlstra
2020-02-13 7:49 ` Michal Simek
2020-02-13 8:11 ` Peter Zijlstra
2020-02-13 8:12 ` Michal Simek
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