From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, Dave Hansen <dave.hansen@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Nicholas Piggin <npiggin@gmail.com>,
Russell King <linux@armlinux.org.uk>,
linux-arm-kernel@lists.infradead.org,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH 7/8] membarrier: Remove arm (32) support for SYNC_CORE
Date: Wed, 16 Jun 2021 12:20:06 +0200 [thread overview]
Message-ID: <YMnQVoKvM5G34Yan@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YMnPezLs6vb418Wz@hirez.programming.kicks-ass.net>
On Wed, Jun 16, 2021 at 12:16:27PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 15, 2021 at 08:21:12PM -0700, Andy Lutomirski wrote:
> > On arm32, the only way to safely flush icache from usermode is to call
> > cacheflush(2). This also handles any required pipeline flushes, so
> > membarrier's SYNC_CORE feature is useless on arm. Remove it.
>
> So SYNC_CORE is there to help an architecture that needs to do something
> per CPU. If I$ invalidation is broadcast and I$ invalidation also
> triggers the flush of any uarch caches derived from it (if there are
> any).
Incomplete sentence there: + then we don't need SYNC_CORE.
> Now arm_syscall() NR(cacheflush) seems to do flush_icache_user_range(),
> which, if I read things right, end up in arch/arm/mm/*.S, but that
> doesn't consider cache_ops_need_broadcast().
>
> Will suggests that perhaps ARM 11MPCore might need this due to their I$
> flush maybe not being broadcast
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, Dave Hansen <dave.hansen@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Nicholas Piggin <npiggin@gmail.com>,
Russell King <linux@armlinux.org.uk>,
linux-arm-kernel@lists.infradead.org,
Will Deacon <will@kernel.org>
Subject: Re: [PATCH 7/8] membarrier: Remove arm (32) support for SYNC_CORE
Date: Wed, 16 Jun 2021 12:20:06 +0200 [thread overview]
Message-ID: <YMnQVoKvM5G34Yan@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YMnPezLs6vb418Wz@hirez.programming.kicks-ass.net>
On Wed, Jun 16, 2021 at 12:16:27PM +0200, Peter Zijlstra wrote:
> On Tue, Jun 15, 2021 at 08:21:12PM -0700, Andy Lutomirski wrote:
> > On arm32, the only way to safely flush icache from usermode is to call
> > cacheflush(2). This also handles any required pipeline flushes, so
> > membarrier's SYNC_CORE feature is useless on arm. Remove it.
>
> So SYNC_CORE is there to help an architecture that needs to do something
> per CPU. If I$ invalidation is broadcast and I$ invalidation also
> triggers the flush of any uarch caches derived from it (if there are
> any).
Incomplete sentence there: + then we don't need SYNC_CORE.
> Now arm_syscall() NR(cacheflush) seems to do flush_icache_user_range(),
> which, if I read things right, end up in arch/arm/mm/*.S, but that
> doesn't consider cache_ops_need_broadcast().
>
> Will suggests that perhaps ARM 11MPCore might need this due to their I$
> flush maybe not being broadcast
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-06-16 10:21 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=YMnQVoKvM5G34Yan@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=dave.hansen@intel.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux@armlinux.org.uk \
--cc=luto@kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=npiggin@gmail.com \
--cc=will@kernel.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.