From: Anatoly Pugachev <matorola@gmail.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Jens Axboe <axboe@kernel.dk>,
"David S . Miller" <davem@davemloft.net>,
linux-arch@vger.kernel.org,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org,
Peter Zijlstra <peterz@infradead.org>,
Sparc kernel list <sparclinux@vger.kernel.org>
Subject: Re: [PATCH v2 3/4] sparc64: remove mm_cpumask clearing to fix kthread_use_mm race
Date: Mon, 14 Sep 2020 13:23:58 +0300 [thread overview]
Message-ID: <CADxRZqxkB9tzO+nf56vFfvdYBooo1rqEbst=QGZQJA3jWhKLYw@mail.gmail.com> (raw)
In-Reply-To: <1600066040.vnmz9nxhwt.astroid@bobo.none>
On Mon, Sep 14, 2020 at 10:00 AM Nicholas Piggin <npiggin@gmail.com> wrote:
>
> Excerpts from Nicholas Piggin's message of September 14, 2020 2:52 pm:
>
> [...]
>
> > 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.
>
> So this compiles and boots on qemu, but qemu does not support any
> sparc64 machines with SMP. Attempting some simple hacks doesn't get
> me far because openbios isn't populating an SMP device tree, which
> blows up everywhere.
>
> The patch is _relatively_ simple, hopefully it shouldn't explode, so
> it's probably ready for testing on real SMP hardware, if someone has
> a few cycles.
Nick,
applied this patch to over 'v5.9-rc5' tag , used my test VM (ldom)
with 32 vcpus.
Machine boot, stress-ng test ( run as
"stress-ng --cpu 8 --io 8 --vm 8 --vm-bytes 2G --fork 8 --timeout 15m" )
finishes without errors.
WARNING: multiple messages have this Message-ID (diff)
From: Anatoly Pugachev <matorola@gmail.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Jens Axboe <axboe@kernel.dk>,
"David S . Miller" <davem@davemloft.net>,
linux-arch@vger.kernel.org,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linuxppc-dev@lists.ozlabs.org,
Peter Zijlstra <peterz@infradead.org>,
Sparc kernel list <sparclinux@vger.kernel.org>
Subject: Re: [PATCH v2 3/4] sparc64: remove mm_cpumask clearing to fix kthread_use_mm race
Date: Mon, 14 Sep 2020 10:23:58 +0000 [thread overview]
Message-ID: <CADxRZqxkB9tzO+nf56vFfvdYBooo1rqEbst=QGZQJA3jWhKLYw@mail.gmail.com> (raw)
In-Reply-To: <1600066040.vnmz9nxhwt.astroid@bobo.none>
On Mon, Sep 14, 2020 at 10:00 AM Nicholas Piggin <npiggin@gmail.com> wrote:
>
> Excerpts from Nicholas Piggin's message of September 14, 2020 2:52 pm:
>
> [...]
>
> > 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.
>
> So this compiles and boots on qemu, but qemu does not support any
> sparc64 machines with SMP. Attempting some simple hacks doesn't get
> me far because openbios isn't populating an SMP device tree, which
> blows up everywhere.
>
> The patch is _relatively_ simple, hopefully it shouldn't explode, so
> it's probably ready for testing on real SMP hardware, if someone has
> a few cycles.
Nick,
applied this patch to over 'v5.9-rc5' tag , used my test VM (ldom)
with 32 vcpus.
Machine boot, stress-ng test ( run as
"stress-ng --cpu 8 --io 8 --vm 8 --vm-bytes 2G --fork 8 --timeout 15m" )
finishes without errors.
WARNING: multiple messages have this Message-ID (diff)
From: Anatoly Pugachev <matorola@gmail.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-arch@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org,
Sparc kernel list <sparclinux@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
linuxppc-dev@lists.ozlabs.org,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH v2 3/4] sparc64: remove mm_cpumask clearing to fix kthread_use_mm race
Date: Mon, 14 Sep 2020 13:23:58 +0300 [thread overview]
Message-ID: <CADxRZqxkB9tzO+nf56vFfvdYBooo1rqEbst=QGZQJA3jWhKLYw@mail.gmail.com> (raw)
In-Reply-To: <1600066040.vnmz9nxhwt.astroid@bobo.none>
On Mon, Sep 14, 2020 at 10:00 AM Nicholas Piggin <npiggin@gmail.com> wrote:
>
> Excerpts from Nicholas Piggin's message of September 14, 2020 2:52 pm:
>
> [...]
>
> > 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.
>
> So this compiles and boots on qemu, but qemu does not support any
> sparc64 machines with SMP. Attempting some simple hacks doesn't get
> me far because openbios isn't populating an SMP device tree, which
> blows up everywhere.
>
> The patch is _relatively_ simple, hopefully it shouldn't explode, so
> it's probably ready for testing on real SMP hardware, if someone has
> a few cycles.
Nick,
applied this patch to over 'v5.9-rc5' tag , used my test VM (ldom)
with 32 vcpus.
Machine boot, stress-ng test ( run as
"stress-ng --cpu 8 --io 8 --vm 8 --vm-bytes 2G --fork 8 --timeout 15m" )
finishes without errors.
next prev parent reply other threads:[~2020-09-14 10:24 UTC|newest]
Thread overview: 49+ 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 ` Nicholas Piggin
2020-09-14 4:52 ` 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 4:52 ` Nicholas Piggin
2020-09-14 4:52 ` Nicholas Piggin
2020-09-14 10:56 ` peterz
2020-09-14 10:56 ` peterz
2020-09-14 10:56 ` peterz
2020-09-15 2:48 ` Nicholas Piggin
2020-09-15 2:48 ` Nicholas Piggin
2020-09-15 2:48 ` Nicholas Piggin
2020-09-15 11:26 ` Michael Ellerman
2020-09-15 11:26 ` Michael Ellerman
2020-09-15 11:26 ` Michael Ellerman
2020-09-18 12:18 ` Michael Ellerman
2020-09-18 12:18 ` 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 ` Nicholas Piggin
2020-09-14 4:52 ` 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 4:52 ` Nicholas Piggin
2020-09-14 4:52 ` Nicholas Piggin
2020-09-14 7:00 ` Nicholas Piggin
2020-09-14 7:00 ` Nicholas Piggin
2020-09-14 7:00 ` Nicholas Piggin
2020-09-14 10:23 ` Anatoly Pugachev [this message]
2020-09-14 10:23 ` Anatoly Pugachev
2020-09-14 10:23 ` Anatoly Pugachev
2020-09-14 10:23 ` Anatoly Pugachev
2020-09-15 2:49 ` Nicholas Piggin
2020-09-15 2:49 ` Nicholas Piggin
2020-09-15 2:49 ` Nicholas Piggin
2020-09-14 19:59 ` David Miller
2020-09-14 19:59 ` David Miller
2020-09-14 19:59 ` David Miller
2020-09-15 3:24 ` Nicholas Piggin
2020-09-15 3:24 ` Nicholas Piggin
2020-09-15 3:24 ` Nicholas Piggin
2020-09-15 19:42 ` David Miller
2020-09-15 19:42 ` David Miller
2020-09-15 19:42 ` David Miller
2020-09-14 4:52 ` [PATCH v2 4/4] powerpc/64s/radix: Fix mm_cpumask trimming race vs kthread_use_mm Nicholas Piggin
2020-09-14 4:52 ` Nicholas Piggin
2020-09-14 4:52 ` Nicholas Piggin
2020-09-24 12:28 ` [PATCH v2 0/4] more mm switching vs TLB shootdown and lazy tlb fixes Michael Ellerman
2020-09-24 12:28 ` Michael Ellerman
2020-09-24 12:28 ` Michael Ellerman
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