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From: Mark Rutland <mark.rutland@arm.com>
To: Alex Belits <abelits@marvell.com>
Cc: "frederic@kernel.org" <frederic@kernel.org>,
	"rostedt@goodmis.org" <rostedt@goodmis.org>,
	Prasun Kapoor <pkapoor@marvell.com>,
	"mingo@kernel.org" <mingo@kernel.org>,
	"davem@davemloft.net" <davem@davemloft.net>,
	"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"will@kernel.org" <will@kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH v3 03/13] task_isolation: add instruction synchronization memory barrier
Date: Wed, 15 Apr 2020 13:44:27 +0100
Message-ID: <20200415124427.GB28304@C02TD0UTHF1T.local> (raw)
In-Reply-To: <d995795c731d6ecceb36bdf1c1df3d72fefd023d.camel@marvell.com>

On Thu, Apr 09, 2020 at 03:17:40PM +0000, Alex Belits wrote:
> Some architectures implement memory synchronization instructions for
> instruction cache. Make a separate kind of barrier that calls them.

Modifying the instruction caches requries more than an ISB, and the
'IMB' naming implies you're trying to order against memory accesses,
which isn't what ISB (generally) does.

What exactly do you want to use this for?

As-is, I don't think this makes sense as a generic barrier.

Thanks,
Mark.

> 
> Signed-off-by: Alex Belits <abelits@marvell.com>
> ---
>  arch/arm/include/asm/barrier.h   | 2 ++
>  arch/arm64/include/asm/barrier.h | 2 ++
>  include/asm-generic/barrier.h    | 4 ++++
>  3 files changed, 8 insertions(+)
> 
> diff --git a/arch/arm/include/asm/barrier.h b/arch/arm/include/asm/barrier.h
> index 83ae97c049d9..6def62c95937 100644
> --- a/arch/arm/include/asm/barrier.h
> +++ b/arch/arm/include/asm/barrier.h
> @@ -64,12 +64,14 @@ extern void arm_heavy_mb(void);
>  #define mb()		__arm_heavy_mb()
>  #define rmb()		dsb()
>  #define wmb()		__arm_heavy_mb(st)
> +#define imb()		isb()
>  #define dma_rmb()	dmb(osh)
>  #define dma_wmb()	dmb(oshst)
>  #else
>  #define mb()		barrier()
>  #define rmb()		barrier()
>  #define wmb()		barrier()
> +#define imb()		barrier()
>  #define dma_rmb()	barrier()
>  #define dma_wmb()	barrier()
>  #endif
> diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h
> index 7d9cc5ec4971..12a7dbd68bed 100644
> --- a/arch/arm64/include/asm/barrier.h
> +++ b/arch/arm64/include/asm/barrier.h
> @@ -45,6 +45,8 @@
>  #define rmb()		dsb(ld)
>  #define wmb()		dsb(st)
>  
> +#define imb()		isb()
> +
>  #define dma_rmb()	dmb(oshld)
>  #define dma_wmb()	dmb(oshst)
>  
> diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h
> index 85b28eb80b11..d5a822fb3e92 100644
> --- a/include/asm-generic/barrier.h
> +++ b/include/asm-generic/barrier.h
> @@ -46,6 +46,10 @@
>  #define dma_wmb()	wmb()
>  #endif
>  
> +#ifndef imb
> +#define imb		barrier()
> +#endif
> +
>  #ifndef read_barrier_depends
>  #define read_barrier_depends()		do { } while (0)
>  #endif
> -- 
> 2.20.1
> 

  reply index

Thread overview: 71+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-04 16:01 [PATCH 00/12] "Task_isolation" mode Alex Belits
2020-03-04 16:03 ` [PATCH 01/12] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-03-04 16:04 ` [PATCH 02/12] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-03-04 16:07 ` [PATCH 03/12] task_isolation: userspace hard isolation from kernel Alex Belits
2020-03-05 18:33   ` Frederic Weisbecker
2020-03-08  5:32     ` [EXT] " Alex Belits
2020-04-28 14:12     ` Marcelo Tosatti
2020-03-06 15:26   ` Frederic Weisbecker
2020-03-08  6:06     ` [EXT] " Alex Belits
2020-03-06 16:00   ` Frederic Weisbecker
2020-03-08  7:16     ` [EXT] " Alex Belits
2020-03-04 16:08 ` [PATCH 04/12] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-03-04 16:09 ` [PATCH 05/12] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-03-04 16:10 ` [PATCH 06/12] task_isolation: arch/arm64: " Alex Belits
2020-03-04 16:31   ` Mark Rutland
2020-03-08  4:48     ` [EXT] " Alex Belits
2020-03-04 16:11 ` [PATCH 07/12] task_isolation: arch/arm: " Alex Belits
2020-03-04 16:12 ` [PATCH 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-03-06 16:03   ` Frederic Weisbecker
2020-03-08  7:28     ` [EXT] " Alex Belits
2020-03-09  2:38       ` Frederic Weisbecker
2020-03-04 16:13 ` [PATCH 09/12] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-03-04 16:14 ` [PATCH 10/12] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-03-04 16:15 ` [PATCH 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-03-06 15:34   ` Frederic Weisbecker
2020-03-08  6:48     ` [EXT] " Alex Belits
2020-03-09  2:28       ` Frederic Weisbecker
2020-03-04 16:16 ` [PATCH 12/12] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits
2020-03-08  3:42 ` [PATCH v2 00/12] "Task_isolation" mode Alex Belits
2020-03-08  3:44   ` [PATCH v2 01/12] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-03-08  3:46   ` [PATCH v2 02/12] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-03-08  3:47   ` [PATCH v2 03/12] task_isolation: userspace hard isolation from kernel Alex Belits
     [not found]     ` <20200307214254.7a8f6c22@hermes.lan>
2020-03-08  7:33       ` [EXT] " Alex Belits
2020-03-27  8:42     ` Marta Rybczynska
2020-04-06  4:31     ` Kevyn-Alexandre Paré
2020-04-06  4:43     ` Kevyn-Alexandre Paré
2020-03-08  3:48   ` [PATCH v2 04/12] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-03-08  3:49   ` [PATCH v2 05/12] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-03-08  3:50   ` [PATCH v2 06/12] task_isolation: arch/arm64: " Alex Belits
2020-03-09 16:59     ` Mark Rutland
2020-03-08  3:52   ` [PATCH v2 07/12] task_isolation: arch/arm: " Alex Belits
2020-03-08  3:53   ` [PATCH v2 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-03-08  3:54   ` [PATCH v2 09/12] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-03-08  3:55   ` [PATCH v2 10/12] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-04-06  4:27     ` Kevyn-Alexandre Paré
2020-03-08  3:56   ` [PATCH v2 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-03-08  3:57   ` [PATCH v2 12/12] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits
2020-04-09 15:09   ` [PATCH v3 00/13] "Task_isolation" mode Alex Belits
2020-04-09 15:15     ` [PATCH 01/13] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-04-09 15:16     ` [PATCH 02/13] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-04-09 15:17     ` [PATCH v3 03/13] task_isolation: add instruction synchronization memory barrier Alex Belits
2020-04-15 12:44       ` Mark Rutland [this message]
2020-04-19  5:02         ` [EXT] " Alex Belits
2020-04-20 12:23           ` Will Deacon
2020-04-20 12:36             ` Mark Rutland
2020-04-20 13:55               ` Will Deacon
2020-04-21  7:41                 ` Will Deacon
2020-04-20 12:45           ` Mark Rutland
2020-04-09 15:20     ` [PATCH v3 04/13] task_isolation: userspace hard isolation from kernel Alex Belits
2020-04-09 18:00       ` Andy Lutomirski
2020-04-19  5:07         ` Alex Belits
2020-04-09 15:21     ` [PATCH 05/13] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-04-09 15:22     ` [PATCH 06/13] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-04-09 15:23     ` [PATCH v3 07/13] task_isolation: arch/arm64: " Alex Belits
2020-04-22 12:08       ` Catalin Marinas
2020-04-09 15:24     ` [PATCH v3 08/13] task_isolation: arch/arm: " Alex Belits
2020-04-09 15:25     ` [PATCH v3 09/13] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-04-09 15:26     ` [PATCH v3 10/13] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-04-09 15:27     ` [PATCH v3 11/13] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-04-09 15:27     ` [PATCH v3 12/13] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-04-09 15:28     ` [PATCH v3 13/13] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits

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