From: Andy Lutomirski <luto@kernel.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: x86 <x86@kernel.org>, Dave Hansen <dave.hansen@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Nicholas Piggin <npiggin@gmail.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH 8/8] membarrier: Rewrite sync_core_before_usermode() and improve documentation
Date: Thu, 17 Jun 2021 17:12:15 -0700 [thread overview]
Message-ID: <26196903-4aee-33c4-bed8-8bf8c7b46793@kernel.org> (raw)
In-Reply-To: <827549827.10547.1623941277868.JavaMail.zimbra@efficios.com>
On 6/17/21 7:47 AM, Mathieu Desnoyers wrote:
> Please change back this #ifndef / #else / #endif within function for
>
> if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE)) {
> ...
> } else {
> ...
> }
>
> I don't think mixing up preprocessor and code logic makes it more readable.
I agree, but I don't know how to make the result work well.
membarrier_sync_core_before_usermode() isn't defined in the !IS_ENABLED
case, so either I need to fake up a definition or use #ifdef.
If I faked up a definition, I would want to assert, at build time, that
it isn't called. I don't think we can do:
static void membarrier_sync_core_before_usermode()
{
BUILD_BUG_IF_REACHABLE();
}
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>, linux-mm <linux-mm@kvack.org>,
Peter Zijlstra <peterz@infradead.org>, x86 <x86@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Paul Mackerras <paulus@samba.org>,
stable <stable@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 8/8] membarrier: Rewrite sync_core_before_usermode() and improve documentation
Date: Thu, 17 Jun 2021 17:12:15 -0700 [thread overview]
Message-ID: <26196903-4aee-33c4-bed8-8bf8c7b46793@kernel.org> (raw)
In-Reply-To: <827549827.10547.1623941277868.JavaMail.zimbra@efficios.com>
On 6/17/21 7:47 AM, Mathieu Desnoyers wrote:
> Please change back this #ifndef / #else / #endif within function for
>
> if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE)) {
> ...
> } else {
> ...
> }
>
> I don't think mixing up preprocessor and code logic makes it more readable.
I agree, but I don't know how to make the result work well.
membarrier_sync_core_before_usermode() isn't defined in the !IS_ENABLED
case, so either I need to fake up a definition or use #ifdef.
If I faked up a definition, I would want to assert, at build time, that
it isn't called. I don't think we can do:
static void membarrier_sync_core_before_usermode()
{
BUILD_BUG_IF_REACHABLE();
}
WARNING: multiple messages have this Message-ID (diff)
From: Andy Lutomirski <luto@kernel.org>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: x86 <x86@kernel.org>, Dave Hansen <dave.hansen@intel.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Nicholas Piggin <npiggin@gmail.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Peter Zijlstra <peterz@infradead.org>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH 8/8] membarrier: Rewrite sync_core_before_usermode() and improve documentation
Date: Thu, 17 Jun 2021 17:12:15 -0700 [thread overview]
Message-ID: <26196903-4aee-33c4-bed8-8bf8c7b46793@kernel.org> (raw)
In-Reply-To: <827549827.10547.1623941277868.JavaMail.zimbra@efficios.com>
On 6/17/21 7:47 AM, Mathieu Desnoyers wrote:
> Please change back this #ifndef / #else / #endif within function for
>
> if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE)) {
> ...
> } else {
> ...
> }
>
> I don't think mixing up preprocessor and code logic makes it more readable.
I agree, but I don't know how to make the result work well.
membarrier_sync_core_before_usermode() isn't defined in the !IS_ENABLED
case, so either I need to fake up a definition or use #ifdef.
If I faked up a definition, I would want to assert, at build time, that
it isn't called. I don't think we can do:
static void membarrier_sync_core_before_usermode()
{
BUILD_BUG_IF_REACHABLE();
}
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next prev parent reply other threads:[~2021-06-18 0:12 UTC|newest]
Thread overview: 165+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-16 3:21 [PATCH 0/8] membarrier cleanups Andy Lutomirski
2021-06-16 3:21 ` [PATCH 1/8] membarrier: Document why membarrier() works Andy Lutomirski
2021-06-16 4:00 ` Nicholas Piggin
2021-06-16 7:30 ` Peter Zijlstra
2021-06-17 23:45 ` Andy Lutomirski
2021-06-16 3:21 ` [PATCH 2/8] x86/mm: Handle unlazying membarrier core sync in the arch code Andy Lutomirski
2021-06-16 4:25 ` Nicholas Piggin
2021-06-16 18:31 ` Andy Lutomirski
2021-06-16 17:49 ` Mathieu Desnoyers
2021-06-16 17:49 ` Mathieu Desnoyers
2021-06-16 18:31 ` Andy Lutomirski
2021-06-16 3:21 ` [PATCH 3/8] membarrier: Remove membarrier_arch_switch_mm() prototype in core code Andy Lutomirski
2021-06-16 4:26 ` Nicholas Piggin
2021-06-16 17:52 ` Mathieu Desnoyers
2021-06-16 17:52 ` Mathieu Desnoyers
2021-06-16 3:21 ` [PATCH 4/8] membarrier: Make the post-switch-mm barrier explicit Andy Lutomirski
2021-06-16 4:19 ` Nicholas Piggin
2021-06-16 7:35 ` Peter Zijlstra
2021-06-16 18:41 ` Andy Lutomirski
2021-06-17 1:37 ` Nicholas Piggin
2021-06-17 2:57 ` Andy Lutomirski
2021-06-17 5:32 ` Andy Lutomirski
2021-06-17 6:51 ` Nicholas Piggin
2021-06-17 23:49 ` Andy Lutomirski
2021-06-19 2:53 ` Nicholas Piggin
2021-06-19 3:20 ` Andy Lutomirski
2021-06-19 4:27 ` Nicholas Piggin
2021-06-17 9:08 ` [RFC][PATCH] sched: Use lightweight hazard pointers to grab lazy mms Peter Zijlstra
2021-06-17 9:10 ` Peter Zijlstra
2021-06-17 10:00 ` Nicholas Piggin
2021-06-17 9:13 ` Peter Zijlstra
2021-06-17 14:06 ` Andy Lutomirski
2021-06-17 9:28 ` Peter Zijlstra
2021-06-17 14:03 ` Andy Lutomirski
2021-06-17 14:10 ` Andy Lutomirski
2021-06-17 15:45 ` Peter Zijlstra
2021-06-18 3:29 ` Paul E. McKenney
2021-06-18 5:04 ` Andy Lutomirski
2021-06-17 15:02 ` [PATCH 4/8] membarrier: Make the post-switch-mm barrier explicit Paul E. McKenney
2021-06-18 0:06 ` Andy Lutomirski
2021-06-18 3:35 ` Paul E. McKenney
2021-06-17 8:45 ` Peter Zijlstra
2021-06-16 3:21 ` [PATCH 5/8] membarrier, kthread: Use _ONCE accessors for task->mm Andy Lutomirski
2021-06-16 4:28 ` Nicholas Piggin
2021-06-16 18:08 ` Mathieu Desnoyers
2021-06-16 18:08 ` Mathieu Desnoyers
2021-06-16 18:45 ` Andy Lutomirski
2021-06-16 3:21 ` [PATCH 6/8] powerpc/membarrier: Remove special barrier on mm switch Andy Lutomirski
2021-06-16 3:21 ` Andy Lutomirski
2021-06-16 4:36 ` Nicholas Piggin
2021-06-16 4:36 ` Nicholas Piggin
2021-06-16 3:21 ` [PATCH 7/8] membarrier: Remove arm (32) support for SYNC_CORE Andy Lutomirski
2021-06-16 3:21 ` Andy Lutomirski
2021-06-16 9:28 ` Russell King (Oracle)
2021-06-16 9:28 ` Russell King (Oracle)
2021-06-16 10:16 ` Peter Zijlstra
2021-06-16 10:16 ` Peter Zijlstra
2021-06-16 10:20 ` Peter Zijlstra
2021-06-16 10:20 ` Peter Zijlstra
2021-06-16 10:34 ` Russell King (Oracle)
2021-06-16 10:34 ` Russell King (Oracle)
2021-06-16 11:10 ` Peter Zijlstra
2021-06-16 11:10 ` Peter Zijlstra
2021-06-16 13:22 ` Russell King (Oracle)
2021-06-16 13:22 ` Russell King (Oracle)
2021-06-16 15:04 ` Catalin Marinas
2021-06-16 15:04 ` Catalin Marinas
2021-06-16 15:23 ` Russell King (Oracle)
2021-06-16 15:23 ` Russell King (Oracle)
2021-06-16 15:45 ` Catalin Marinas
2021-06-16 15:45 ` Catalin Marinas
2021-06-16 16:00 ` Catalin Marinas
2021-06-16 16:00 ` Catalin Marinas
2021-06-16 16:27 ` Russell King (Oracle)
2021-06-16 16:27 ` Russell King (Oracle)
2021-06-17 8:55 ` Krzysztof Hałasa
2021-06-17 8:55 ` Krzysztof Hałasa
2021-06-17 8:55 ` Krzysztof Hałasa
2021-06-18 12:54 ` Linus Walleij
2021-06-18 12:54 ` Linus Walleij
2021-06-18 12:54 ` Linus Walleij
2021-06-18 13:19 ` Russell King (Oracle)
2021-06-18 13:19 ` Russell King (Oracle)
2021-06-18 13:36 ` Arnd Bergmann
2021-06-18 13:36 ` Arnd Bergmann
2021-06-18 13:36 ` Arnd Bergmann
2021-06-17 10:40 ` Mark Rutland
2021-06-17 10:40 ` Mark Rutland
2021-06-17 11:23 ` Russell King (Oracle)
2021-06-17 11:23 ` Russell King (Oracle)
2021-06-17 11:33 ` Mark Rutland
2021-06-17 11:33 ` Mark Rutland
2021-06-17 13:41 ` Andy Lutomirski
2021-06-17 13:41 ` Andy Lutomirski
2021-06-17 13:51 ` Mark Rutland
2021-06-17 13:51 ` Mark Rutland
2021-06-17 14:00 ` Andy Lutomirski
2021-06-17 14:00 ` Andy Lutomirski
2021-06-17 14:20 ` Mark Rutland
2021-06-17 14:20 ` Mark Rutland
2021-06-17 15:01 ` Peter Zijlstra
2021-06-17 15:01 ` Peter Zijlstra
2021-06-17 15:13 ` Peter Zijlstra
2021-06-17 15:13 ` Peter Zijlstra
2021-06-17 14:16 ` Mathieu Desnoyers
2021-06-17 14:16 ` Mathieu Desnoyers
2021-06-17 14:05 ` Peter Zijlstra
2021-06-17 14:05 ` Peter Zijlstra
2021-06-18 0:07 ` Andy Lutomirski
2021-06-18 0:07 ` Andy Lutomirski
2021-06-16 3:21 ` [PATCH 8/8] membarrier: Rewrite sync_core_before_usermode() and improve documentation Andy Lutomirski
2021-06-16 3:21 ` Andy Lutomirski
2021-06-16 3:21 ` Andy Lutomirski
2021-06-16 4:45 ` Nicholas Piggin
2021-06-16 4:45 ` Nicholas Piggin
2021-06-16 4:45 ` Nicholas Piggin
2021-06-16 18:52 ` Andy Lutomirski
2021-06-16 18:52 ` Andy Lutomirski
2021-06-16 18:52 ` Andy Lutomirski
2021-06-16 23:48 ` Andy Lutomirski
2021-06-16 23:48 ` Andy Lutomirski
2021-06-16 23:48 ` Andy Lutomirski
2021-06-18 15:27 ` Christophe Leroy
2021-06-18 15:27 ` Christophe Leroy
2021-06-18 15:27 ` Christophe Leroy
2021-06-16 10:20 ` Will Deacon
2021-06-16 10:20 ` Will Deacon
2021-06-16 10:20 ` Will Deacon
2021-06-16 23:58 ` Andy Lutomirski
2021-06-16 23:58 ` Andy Lutomirski
2021-06-16 23:58 ` Andy Lutomirski
2021-06-17 14:47 ` Mathieu Desnoyers
2021-06-17 14:47 ` Mathieu Desnoyers
2021-06-17 14:47 ` Mathieu Desnoyers
2021-06-17 14:47 ` Mathieu Desnoyers
2021-06-18 0:12 ` Andy Lutomirski [this message]
2021-06-18 0:12 ` Andy Lutomirski
2021-06-18 0:12 ` Andy Lutomirski
2021-06-18 16:31 ` Mathieu Desnoyers
2021-06-18 16:31 ` Mathieu Desnoyers
2021-06-18 16:31 ` Mathieu Desnoyers
2021-06-18 16:31 ` Mathieu Desnoyers
2021-06-18 19:58 ` Andy Lutomirski
2021-06-18 19:58 ` Andy Lutomirski
2021-06-18 19:58 ` Andy Lutomirski
2021-06-18 20:09 ` Mathieu Desnoyers
2021-06-18 20:09 ` Mathieu Desnoyers
2021-06-18 20:09 ` Mathieu Desnoyers
2021-06-18 20:09 ` Mathieu Desnoyers
2021-06-19 6:02 ` Nicholas Piggin
2021-06-19 6:02 ` Nicholas Piggin
2021-06-19 6:02 ` Nicholas Piggin
2021-06-19 15:50 ` Andy Lutomirski
2021-06-19 15:50 ` Andy Lutomirski
2021-06-19 15:50 ` Andy Lutomirski
2021-06-20 2:10 ` Nicholas Piggin
2021-06-20 2:10 ` Nicholas Piggin
2021-06-20 2:10 ` Nicholas Piggin
2021-06-17 15:16 ` Mathieu Desnoyers
2021-06-17 15:16 ` Mathieu Desnoyers
2021-06-17 15:16 ` Mathieu Desnoyers
2021-06-17 15:16 ` Mathieu Desnoyers
2021-06-18 0:13 ` Andy Lutomirski
2021-06-18 0:13 ` Andy Lutomirski
2021-06-18 0:13 ` Andy Lutomirski
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