From: David Miller <davem@davemloft.net>
To: npiggin@gmail.com
Cc: axboe@kernel.dk, linux-arch@vger.kernel.org,
peterz@infradead.org, aneesh.kumar@linux.ibm.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
sparclinux@vger.kernel.org, akpm@linux-foundation.org,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 3/4] sparc64: remove mm_cpumask clearing to fix kthread_use_mm race
Date: Tue, 15 Sep 2020 12:42:54 -0700 (PDT) [thread overview]
Message-ID: <20200915.124254.1657521903825160294.davem@davemloft.net> (raw)
In-Reply-To: <1600139445.qwycwjuwdq.astroid@bobo.none>
From: Nicholas Piggin <npiggin@gmail.com>
Date: Tue, 15 Sep 2020 13:24:07 +1000
> Excerpts from David Miller's message of September 15, 2020 5:59 am:
>> From: Nicholas Piggin <npiggin@gmail.com>
>> Date: Mon, 14 Sep 2020 14:52:18 +1000
>>
>> ...
>>> The basic fix for sparc64 is to remove its mm_cpumask clearing code. The
>>> optimisation could be effectively restored by sending IPIs to mm_cpumask
>>> members and having them remove themselves from mm_cpumask. This is more
>>> tricky so I leave it as an exercise for someone with a sparc64 SMP.
>>> powerpc has a (currently similarly broken) example.
>>>
>>> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>>
>> Sad to see this optimization go away, but what can I do:
>>
>> Acked-by: David S. Miller <davem@davemloft.net>
>>
>
> Thanks Dave, any objection if we merge this via the powerpc tree
> to keep the commits together?
No objection.
next prev parent reply other threads:[~2020-09-15 19:45 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-14 4:52 [PATCH v2 0/4] more mm switching vs TLB shootdown and lazy tlb fixes Nicholas Piggin
2020-09-14 4:52 ` [PATCH v2 1/4] mm: fix exec activate_mm vs TLB shootdown and lazy tlb switching race Nicholas Piggin
2020-09-14 10:56 ` peterz
2020-09-15 2:48 ` Nicholas Piggin
2020-09-15 11:26 ` Michael Ellerman
2020-09-18 12:18 ` Michael Ellerman
2020-09-14 4:52 ` [PATCH v2 2/4] powerpc: select ARCH_WANT_IRQS_OFF_ACTIVATE_MM Nicholas Piggin
2020-09-14 4:52 ` [PATCH v2 3/4] sparc64: remove mm_cpumask clearing to fix kthread_use_mm race Nicholas Piggin
2020-09-14 7:00 ` Nicholas Piggin
2020-09-14 10:23 ` Anatoly Pugachev
2020-09-15 2:49 ` Nicholas Piggin
2020-09-14 19:59 ` David Miller
2020-09-15 3:24 ` Nicholas Piggin
2020-09-15 19:42 ` David Miller [this message]
2020-09-14 4:52 ` [PATCH v2 4/4] powerpc/64s/radix: Fix mm_cpumask trimming race vs kthread_use_mm Nicholas Piggin
2020-09-24 12:28 ` [PATCH v2 0/4] more mm switching vs TLB shootdown and lazy tlb fixes Michael Ellerman
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