From: gdavis@mvista.com (George G. Davis)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC/PATCH v4 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is not preempt safe
Date: Tue, 18 Oct 2011 19:29:37 -0400 [thread overview]
Message-ID: <20111018232937.GB237@mvista.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1110181732100.17040@xanadu.home>
On Tue, Oct 18, 2011 at 05:52:37PM -0400, Nicolas Pitre wrote:
> On Tue, 18 Oct 2011, gdavis at mvista.com wrote:
>
> > @@ -122,7 +122,22 @@ ENTRY(cpu_v6_switch_mm)
> >
> > ENTRY(cpu_v6_set_pte_ext)
> > #ifdef CONFIG_MMU
> > +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
> > + stmdb sp!, {r4, r5}
> > + get_thread_info r5
> > + ldr r4, [r5, #TI_PREEMPT] @ get preempt count
> > + add r3, r4, #1 @ increment it
> > + str r3, [r5, #TI_PREEMPT] @ disable preempt
> > +#endif
> > armv6_set_pte_ext cpu_v6
> > +#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT)
> > + str r4, [r5, #TI_PREEMPT] @ restore preempt count
> > + teq r4, #0 @ preempt count == 0?
> > + ldreq r4, [r5, #TI_FLAGS] @ load flags if yes
> > + tst r4, #_TIF_NEED_RESCHED @ need resched?
> > + ldmia sp!, {r4, r5}
> > + bne preempt_schedule @ ret via preempt_schedule
> > +#endif
>
> Same issue as previous patch.
Same mistake, I second guessed myself and removed the movne r4, #0
before submitting. : /
> Wouldn't it be better if you disabled interrupts around the small
> critical region within armv6_set_pte_ext instead? That would certainly
> be a lighter solution. Something like:
>
> diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
> index 307a4def8d..9bc2dbfe4e 100644
> --- a/arch/arm/mm/proc-macros.S
> +++ b/arch/arm/mm/proc-macros.S
> @@ -167,8 +167,11 @@
> tstne r1, #L_PTE_PRESENT
> moveq r3, #0
>
> + mrs r2, cpsr
> + cpsid i
> str r3, [r0]
> mcr p15, 0, r0, c7, c10, 1 @ flush_pte
> + msr cpsr_c, r2
> .endm
I do like this better, less overhead than the preempt_{disable,enable}
case.
Thanks!
--
Regards,
George
>
>
> Nicolas
next prev parent reply other threads:[~2011-10-18 23:29 UTC|newest]
Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-20 13:43 parallel load of modules on an ARM multicore EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31)
2011-06-21 15:50 ` Catalin Marinas
2011-06-23 14:39 ` AW: " EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31)
2011-06-23 14:52 ` Catalin Marinas
2011-06-23 15:12 ` Russell King - ARM Linux
2011-06-23 15:34 ` Catalin Marinas
2011-06-23 17:02 ` Catalin Marinas
2011-06-23 15:20 ` AW: " EXTERNAL Waechtler Peter (Fa. TCP, CM-AI/PJ-CF31)
2011-07-07 4:25 ` George G. Davis
2011-10-20 4:04 ` George G. Davis
2011-09-22 7:29 ` George G. Davis
2011-09-22 8:52 ` Catalin Marinas
2011-10-06 4:29 ` George G. Davis
2011-10-06 5:08 ` [RFC/PATCH 0/7] ARM: ARM11 MPCore preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-06 16:35 ` Russell King - ARM Linux
2011-10-06 19:38 ` George G. Davis
2011-10-06 5:08 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-06 5:08 ` [RFC/PATCH 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-06 16:40 ` Russell King - ARM Linux
2011-10-06 19:41 ` George G. Davis
2011-10-06 5:08 ` [RFC/PATCH 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-06 7:46 ` Russell King - ARM Linux
2011-10-06 12:35 ` George G. Davis
2011-10-07 2:38 ` [RFC/PATCH v2 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-07 7:47 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{,_kernel} " Russell King - ARM Linux
2011-10-07 15:31 ` [RFC/PATCH 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} " George G. Davis
2011-10-07 2:38 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-11 9:53 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean,flush}_pmd_entry " Catalin Marinas
2011-10-12 2:34 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " George G. Davis
2011-10-13 14:31 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean,flush}_pmd_entry " Russell King - ARM Linux
2011-10-14 1:34 ` [RFC/PATCH 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " George G. Davis
2011-10-07 2:38 ` [RFC/PATCH 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-11 9:56 ` Catalin Marinas
2011-10-12 6:04 ` gdavis at mvista.com
2011-10-13 14:34 ` Russell King - ARM Linux
2011-10-13 14:49 ` Catalin Marinas
2011-10-13 14:53 ` Russell King - ARM Linux
2011-10-14 1:46 ` George G. Davis
2011-10-14 1:44 ` George G. Davis
2011-10-14 1:42 ` George G. Davis
2011-10-14 2:54 ` Nicolas Pitre
2011-10-14 12:56 ` George G. Davis
2011-10-07 2:38 ` [RFC/PATCH 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-07 2:38 ` [RFC/PATCH 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-07 16:26 ` [RFC/PATCH v3 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 1/7] ARM: ARM11 MPCore: pgd_alloc is not preempt safe gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 2/7] ARM: ARM11 MPCore: pte_alloc_one{, _kernel} are " gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 3/7] ARM: ARM11 MPCore: {clean, flush}_pmd_entry " gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 4/7] ARM: ARM11 MPCore: clean_dcache_area is " gdavis at mvista.com
2011-10-18 17:08 ` Tony Lindgren
2011-10-18 17:30 ` George G. Davis
2011-10-18 17:43 ` Tony Lindgren
2011-10-18 18:13 ` George G. Davis
2011-10-18 13:47 ` [RFC/PATCH v4 5/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2011-10-18 13:47 ` [RFC/PATCH v4 6/7] ARM: ARM11 MPCore: DMA_CACHE_RWFO operations are not preempt safe gdavis at mvista.com
2011-10-18 21:28 ` Nicolas Pitre
2011-10-18 23:26 ` George G. Davis
2011-10-19 1:09 ` Nicolas Pitre
2011-10-18 13:47 ` [RFC/PATCH v4 7/7] ARM: ARM11 MPCore: cpu_v6_set_pte_ext is " gdavis at mvista.com
2011-10-18 21:52 ` Nicolas Pitre
2011-10-18 23:29 ` George G. Davis [this message]
2012-06-12 20:40 ` [RFC/PATCH v5 0/7] ARM11 MPCore: preemption/task migration cache coherency fixups gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 1/7] ARM: ARM11 MPCore: Make pgd_alloc preempt safe gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 2/7] ARM: ARM11 MPCore: Make pte_alloc_one{, _kernel} " gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 3/7] ARM: ARM11 MPCore: Make {clean, flush}_pmd_entry " gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 4/7] ARM: Move get_thread_info macro definition to <asm/assembler.h> gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 5/7] ARM: ARM11 MPCore: cpu_v6_dcache_clean_area needs RFO gdavis at mvista.com
2012-06-13 9:32 ` Catalin Marinas
2012-06-13 9:36 ` Russell King - ARM Linux
2012-06-13 9:41 ` Catalin Marinas
2012-06-13 9:45 ` Russell King - ARM Linux
2012-06-13 9:54 ` Catalin Marinas
2012-06-13 11:36 ` George G. Davis
2012-06-13 11:21 ` George G. Davis
2012-06-12 20:40 ` [RFC/PATCH v5 6/7] ARM: ARM11 MPCore: Make DMA_CACHE_RWFO operations preempt safe gdavis at mvista.com
2012-06-12 20:40 ` [RFC/PATCH v5 7/7] ARM: ARM11 MPCore: Make cpu_v6_set_pte_ext " gdavis at mvista.com
2012-06-13 9:34 ` Catalin Marinas
2012-06-13 11:35 ` George G. Davis
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