From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
yang.shi@windriver.com, benh@kernel.crashing.org,
paulus@samba.org, akpm@linux-foundation.org,
heiko.carstens@de.ibm.com, schwidefsky@de.ibm.com,
borntraeger@de.ibm.com, mst@redhat.com, tglx@linutronix.de,
David.Laight@ACULAB.COM, hughd@google.com, hocko@suse.cz,
ralf@linux-mips.org, herbert@gondor.apana.org.au,
linux@arm.linux.org.uk, airlied@linux.ie,
daniel.vetter@intel.com, linux-mm@kvack.org,
linux-arch@vger.kernel.org, peterz@infradead.org
Subject: Re: [PATCH v1 11/15] arm/futex: UP futex_atomic_op_inuser() relies on disabled preemption
Date: Tue, 12 May 2015 21:00:14 +0200 [thread overview]
Message-ID: <20150512190014.GD25464@linutronix.de> (raw)
In-Reply-To: <1431359540-32227-12-git-send-email-dahi@linux.vnet.ibm.com>
* David Hildenbrand | 2015-05-11 17:52:16 [+0200]:
>The !CONFIG_SMP implementation of futex_atomic_op_inuser() seems to rely
>on disabled preemption to guarantee mutual exclusion.
Yes, this is what the code looks like. It is more the requirement for
ldrex/strex opcodes which are ARMv6+ and so is SMP support (here).
Documentation wise you could replace CONFIG_SMP by
__LINUX_ARM_ARCH__ >= 6
in a later patch if you like. This would be more in-sync with
arch/arm/include/asm/cmpxchg.h :)
Sebastian
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WARNING: multiple messages have this Message-ID (diff)
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: David Hildenbrand <dahi@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
yang.shi@windriver.com, benh@kernel.crashing.org,
paulus@samba.org, akpm@linux-foundation.org,
heiko.carstens@de.ibm.com, schwidefsky@de.ibm.com,
borntraeger@de.ibm.com, mst@redhat.com, tglx@linutronix.de,
David.Laight@ACULAB.COM, hughd@google.com, hocko@suse.cz,
ralf@linux-mips.org, herbert@gondor.apana.org.au,
linux@arm.linux.org.uk, airlied@linux.ie,
daniel.vetter@intel.com, linux-mm@kvack.org,
linux-arch@vger.kernel.org, peterz@infradead.org
Subject: Re: [PATCH v1 11/15] arm/futex: UP futex_atomic_op_inuser() relies on disabled preemption
Date: Tue, 12 May 2015 21:00:14 +0200 [thread overview]
Message-ID: <20150512190014.GD25464@linutronix.de> (raw)
Message-ID: <20150512190014.ADGAGvAI76VUYfZGo1nH7AtUK1266zmP6eViPBHis9Q@z> (raw)
In-Reply-To: <1431359540-32227-12-git-send-email-dahi@linux.vnet.ibm.com>
* David Hildenbrand | 2015-05-11 17:52:16 [+0200]:
>The !CONFIG_SMP implementation of futex_atomic_op_inuser() seems to rely
>on disabled preemption to guarantee mutual exclusion.
Yes, this is what the code looks like. It is more the requirement for
ldrex/strex opcodes which are ARMv6+ and so is SMP support (here).
Documentation wise you could replace CONFIG_SMP by
__LINUX_ARM_ARCH__ >= 6
in a later patch if you like. This would be more in-sync with
arch/arm/include/asm/cmpxchg.h :)
Sebastian
next prev parent reply other threads:[~2015-05-12 19:00 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-11 15:52 [PATCH v1 00/15] decouple pagefault_disable() from preempt_disable() David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 01/15] uaccess: count pagefault_disable() levels in pagefault_disabled David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:18 ` [tip:sched/core] sched/preempt, mm/fault: Count pagefault_disable () " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 02/15] mm, uaccess: trigger might_sleep() in might_fault() with disabled pagefaults David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:18 ` [tip:sched/core] sched/preempt, mm/fault: Trigger " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 03/15] uaccess: clarify that uaccess may only sleep if pagefaults are enabled David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:18 ` [tip:sched/core] mm/uaccess, mm/fault: Clarify " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 04/15] mm: explicitly disable/enable preemption in kmap_atomic_* David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:19 ` [tip:sched/core] sched/preempt, mm/kmap: Explicitly disable/ enable " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 05/15] mips: kmap_coherent relies on disabled preemption David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:19 ` [tip:sched/core] sched/preempt, mm/kmap, MIPS: Disable preemption in kmap_coherent() explicitly tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 06/15] mm: use pagefault_disable() to check for disabled pagefaults in the handler David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:19 ` [tip:sched/core] mm/fault, arch: Use " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 07/15] drm/i915: use pagefault_disabled() to check for disabled pagefaults David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:20 ` [tip:sched/core] mm/fault, drm/i915: Use " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 08/15] futex: UP futex_atomic_op_inuser() relies on disabled preemption David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:20 ` [tip:sched/core] sched/preempt, futex: Disable preemption in UP futex_atomic_op_inuser() explicitly tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 09/15] futex: UP futex_atomic_cmpxchg_inatomic() relies on disabled preemption David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:20 ` [tip:sched/core] sched/preempt, futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 10/15] arm/futex: UP futex_atomic_cmpxchg_inatomic() relies on disabled preemption David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:21 ` [tip:sched/core] sched/preempt, arm/futex: Disable preemption in UP futex_atomic_cmpxchg_inatomic() explicitly tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 11/15] arm/futex: UP futex_atomic_op_inuser() relies on disabled preemption David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-12 19:00 ` Sebastian Andrzej Siewior [this message]
2015-05-12 19:00 ` Sebastian Andrzej Siewior
2015-05-13 7:38 ` David Hildenbrand
2015-05-13 7:38 ` David Hildenbrand
2015-05-13 8:19 ` Sebastian Andrzej Siewior
2015-05-13 8:19 ` Sebastian Andrzej Siewior
2015-05-13 8:55 ` David Hildenbrand
2015-05-13 8:55 ` David Hildenbrand
2015-05-19 7:21 ` [tip:sched/core] sched/preempt, arm/futex: Disable preemption in UP futex_atomic_op_inuser() explicitly tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 12/15] futex: clarify that preemption doesn't have to be disabled David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:21 ` [tip:sched/core] sched/preempt, futex: Update comments to " tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 13/15] powerpc: enable_kernel_altivec() requires disabled preemption David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:22 ` [tip:sched/core] sched/preempt, powerpc: Disable preemption in enable_kernel_altivec() explicitly tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 14/15] mips: properly lock access to the fpu David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:22 ` [tip:sched/core] sched/preempt, MIPS: Properly lock access to the FPU tip-bot for David Hildenbrand
2015-05-11 15:52 ` [PATCH v1 15/15] uaccess: decouple preemption from the pagefault logic David Hildenbrand
2015-05-11 15:52 ` David Hildenbrand
2015-05-19 7:22 ` [tip:sched/core] sched/preempt, mm/fault: Decouple preemption from the page fault logic tip-bot for David Hildenbrand
2015-05-15 14:23 ` [PATCH v1 00/15] decouple pagefault_disable() from preempt_disable() Thomas Gleixner
2015-05-15 14:23 ` Thomas Gleixner
2015-05-18 12:46 ` David Hildenbrand
2015-05-18 12:46 ` David Hildenbrand
2015-05-18 13:04 ` Peter Zijlstra
2015-05-18 13:04 ` Peter Zijlstra
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