From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Anton Blanchard <anton@ozlabs.org>, Arnd Bergmann <arnd@arndb.de>,
linux-arch <linux-arch@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
Andy Lutomirski <luto@amacapital.net>,
Andy Lutomirski <luto@kernel.org>, x86 <x86@kernel.org>
Subject: Re: [RFC PATCH 4/7] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode
Date: Fri, 17 Jul 2020 09:42:43 -0400 (EDT) [thread overview]
Message-ID: <1314561373.18530.1594993363050.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <1594906688.ikv6r4gznx.astroid@bobo.none>
----- On Jul 16, 2020, at 7:26 PM, Nicholas Piggin npiggin@gmail.com wrote:
[...]
>
> membarrier does replace barrier instructions on remote CPUs, which do
> order accesses performed by the kernel on the user address space. So
> membarrier should too I guess.
>
> Normal process context accesses like read(2) will do so because they
> don't get filtered out from IPIs, but kernel threads using the mm may
> not.
But it should not be an issue, because membarrier's ordering is only with respect
to submit and completion of io_uring requests, which are performed through
system calls from the context of user-space threads, which are called from the
right mm.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
WARNING: multiple messages have this Message-ID (diff)
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-arch <linux-arch@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>,
Peter Zijlstra <peterz@infradead.org>, x86 <x86@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
linux-mm <linux-mm@kvack.org>, Andy Lutomirski <luto@kernel.org>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [RFC PATCH 4/7] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode
Date: Fri, 17 Jul 2020 09:42:43 -0400 (EDT) [thread overview]
Message-ID: <1314561373.18530.1594993363050.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <1594906688.ikv6r4gznx.astroid@bobo.none>
----- On Jul 16, 2020, at 7:26 PM, Nicholas Piggin npiggin@gmail.com wrote:
[...]
>
> membarrier does replace barrier instructions on remote CPUs, which do
> order accesses performed by the kernel on the user address space. So
> membarrier should too I guess.
>
> Normal process context accesses like read(2) will do so because they
> don't get filtered out from IPIs, but kernel threads using the mm may
> not.
But it should not be an issue, because membarrier's ordering is only with respect
to submit and completion of io_uring requests, which are performed through
system calls from the context of user-space threads, which are called from the
right mm.
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next prev parent reply other threads:[~2020-07-17 13:42 UTC|newest]
Thread overview: 118+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 1:56 [RFC PATCH 0/7] mmu context cleanup, lazy tlb cleanup, Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 1:56 ` [RFC PATCH 1/7] asm-generic: add generic MMU versions of mmu context functions Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 1:56 ` [RFC PATCH 2/7] arch: use asm-generic mmu context for no-op implementations Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 1:56 ` [RFC PATCH 3/7] mm: introduce exit_lazy_tlb Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 1:56 ` [RFC PATCH 4/7] x86: use exit_lazy_tlb rather than membarrier_mm_sync_core_before_usermode Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 9:42 ` Peter Zijlstra
2020-07-10 9:42 ` Peter Zijlstra
2020-07-10 14:02 ` Mathieu Desnoyers
2020-07-10 14:02 ` Mathieu Desnoyers
2020-07-10 17:04 ` Andy Lutomirski
2020-07-10 17:04 ` Andy Lutomirski
2020-07-13 4:45 ` Nicholas Piggin
2020-07-13 4:45 ` Nicholas Piggin
2020-07-13 13:47 ` Nicholas Piggin
2020-07-13 13:47 ` Nicholas Piggin
2020-07-13 14:13 ` Mathieu Desnoyers
2020-07-13 14:13 ` Mathieu Desnoyers
2020-07-13 15:48 ` Andy Lutomirski
2020-07-13 15:48 ` Andy Lutomirski
2020-07-13 16:37 ` Nicholas Piggin
2020-07-13 16:37 ` Nicholas Piggin
2020-07-16 4:15 ` Nicholas Piggin
2020-07-16 4:15 ` Nicholas Piggin
2020-07-16 4:42 ` Nicholas Piggin
2020-07-16 4:42 ` Nicholas Piggin
2020-07-16 15:46 ` Mathieu Desnoyers
2020-07-16 15:46 ` Mathieu Desnoyers
2020-07-16 16:03 ` Mathieu Desnoyers
2020-07-16 16:03 ` Mathieu Desnoyers
2020-07-16 18:58 ` Mathieu Desnoyers
2020-07-16 18:58 ` Mathieu Desnoyers
2020-07-16 21:24 ` Alan Stern
2020-07-16 21:24 ` Alan Stern
2020-07-17 13:39 ` Mathieu Desnoyers
2020-07-17 13:39 ` Mathieu Desnoyers
2020-07-17 14:51 ` Alan Stern
2020-07-17 14:51 ` Alan Stern
2020-07-17 15:39 ` Mathieu Desnoyers
2020-07-17 15:39 ` Mathieu Desnoyers
2020-07-17 16:11 ` Alan Stern
2020-07-17 16:11 ` Alan Stern
2020-07-17 16:22 ` Mathieu Desnoyers
2020-07-17 16:22 ` Mathieu Desnoyers
2020-07-17 17:44 ` Alan Stern
2020-07-17 17:44 ` Alan Stern
2020-07-17 17:52 ` Mathieu Desnoyers
2020-07-17 17:52 ` Mathieu Desnoyers
2020-07-17 0:00 ` Nicholas Piggin
2020-07-17 0:00 ` Nicholas Piggin
2020-07-16 5:18 ` Andy Lutomirski
2020-07-16 5:18 ` Andy Lutomirski
2020-07-16 6:06 ` Nicholas Piggin
2020-07-16 6:06 ` Nicholas Piggin
2020-07-16 8:50 ` Peter Zijlstra
2020-07-16 8:50 ` Peter Zijlstra
2020-07-16 10:03 ` Nicholas Piggin
2020-07-16 10:03 ` Nicholas Piggin
2020-07-16 11:00 ` peterz
2020-07-16 11:00 ` peterz
2020-07-16 15:34 ` Mathieu Desnoyers
2020-07-16 15:34 ` Mathieu Desnoyers
2020-07-16 23:26 ` Nicholas Piggin
2020-07-16 23:26 ` Nicholas Piggin
2020-07-17 13:42 ` Mathieu Desnoyers [this message]
2020-07-17 13:42 ` Mathieu Desnoyers
2020-07-20 3:03 ` Nicholas Piggin
2020-07-20 3:03 ` Nicholas Piggin
2020-07-20 16:46 ` Mathieu Desnoyers
2020-07-20 16:46 ` Mathieu Desnoyers
2020-07-21 10:04 ` Nicholas Piggin
2020-07-21 10:04 ` Nicholas Piggin
2020-07-21 13:11 ` Mathieu Desnoyers
2020-07-21 13:11 ` Mathieu Desnoyers
2020-07-21 14:30 ` Nicholas Piggin
2020-07-21 14:30 ` Nicholas Piggin
2020-07-21 15:06 ` peterz
2020-07-21 15:06 ` peterz
2020-07-21 15:15 ` Mathieu Desnoyers
2020-07-21 15:15 ` Mathieu Desnoyers
2020-07-21 15:19 ` Peter Zijlstra
2020-07-21 15:19 ` Peter Zijlstra
2020-07-21 15:22 ` Mathieu Desnoyers
2020-07-21 15:22 ` Mathieu Desnoyers
2020-07-10 1:56 ` [RFC PATCH 5/7] lazy tlb: introduce lazy mm refcount helper functions Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 9:48 ` Peter Zijlstra
2020-07-10 9:48 ` Peter Zijlstra
2020-07-10 1:56 ` [RFC PATCH 6/7] lazy tlb: allow lazy tlb mm switching to be configurable Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 1:56 ` [RFC PATCH 7/7] lazy tlb: shoot lazies, a non-refcounting lazy tlb option Nicholas Piggin
2020-07-10 1:56 ` Nicholas Piggin
2020-07-10 9:35 ` Peter Zijlstra
2020-07-10 9:35 ` Peter Zijlstra
2020-07-13 4:58 ` Nicholas Piggin
2020-07-13 4:58 ` Nicholas Piggin
2020-07-13 15:59 ` Andy Lutomirski
2020-07-13 15:59 ` Andy Lutomirski
2020-07-13 16:48 ` Nicholas Piggin
2020-07-13 16:48 ` Nicholas Piggin
2020-07-13 18:18 ` Andy Lutomirski
2020-07-13 18:18 ` Andy Lutomirski
2020-07-14 5:04 ` Nicholas Piggin
2020-07-14 5:04 ` Nicholas Piggin
2020-07-14 6:31 ` Nicholas Piggin
2020-07-14 6:31 ` Nicholas Piggin
2020-07-14 12:46 ` Andy Lutomirski
2020-07-14 12:46 ` Andy Lutomirski
2020-07-14 13:23 ` Peter Zijlstra
2020-07-14 13:23 ` Peter Zijlstra
2020-07-16 2:26 ` Nicholas Piggin
2020-07-16 2:26 ` Nicholas Piggin
2020-07-16 2:35 ` Nicholas Piggin
2020-07-16 2:35 ` Nicholas Piggin
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