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From: Robin Holt <holt@sgi.com>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
	Christoph Lameter <clameter@sgi.com>,
	akpm@linux-foundation.org, Nick Piggin <npiggin@suse.de>,
	Steve Wise <swise@opengridcomputing.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-mm@kvack.org, Kanoj Sarcar <kanojsarcar@yahoo.com>,
	Roland Dreier <rdreier@cisco.com>, Jack Steiner <steiner@sgi.com>,
	linux-kernel@vger.kernel.org, Avi Kivity <avi@qumranet.com>,
	kvm-devel@lists.sourceforge.net, Robin Holt <holt@sgi.com>,
	general@lists.openfabrics.org, Hugh Dickins <hugh@veritas.com>
Subject: Re: [PATCH 1 of 9] Lock the entire mm to prevent any mmu related operation to happen
Date: Fri, 25 Apr 2008 14:25:32 -0500	[thread overview]
Message-ID: <20080425192532.GA19717@sgi.com> (raw)
In-Reply-To: <20080425165639.GA23300@duo.random>

On Fri, Apr 25, 2008 at 06:56:40PM +0200, Andrea Arcangeli wrote:
> Fortunately I figured out we don't really need mm_lock in unregister
> because it's ok to unregister in the middle of the range_begin/end
> critical section (that's definitely not ok for register that's why
> register needs mm_lock). And it's perfectly ok to fail in register().

I think you still need mm_lock (unless I miss something).  What happens
when one callout is scanning mmu_notifier_invalidate_range_start() and
you unlink.  That list next pointer with LIST_POISON1 which is a really
bad address for the processor to track.

Maybe I misunderstood your description.

Thanks,
Robin

WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: Nick Piggin <npiggin@suse.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	kvm-devel@lists.sourceforge.net,
	Kanoj Sarcar <kanojsarcar@yahoo.com>,
	Roland Dreier <rdreier@cisco.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	linux-kernel@vger.kernel.org, Avi Kivity <avi@qumranet.com>,
	linux-mm@kvack.org, Robin Holt <holt@sgi.com>,
	general@lists.openfabrics.org, Hugh Dickins <hugh@veritas.com>,
	akpm@linux-foundation.org, Jack Steiner <steiner@sgi.com>,
	Christoph Lameter <clameter@sgi.com>
Subject: [ofa-general] Re: [PATCH 1 of 9] Lock the entire mm to prevent any mmu related operation to happen
Date: Fri, 25 Apr 2008 14:25:32 -0500	[thread overview]
Message-ID: <20080425192532.GA19717@sgi.com> (raw)
In-Reply-To: <20080425165639.GA23300@duo.random>

On Fri, Apr 25, 2008 at 06:56:40PM +0200, Andrea Arcangeli wrote:
> Fortunately I figured out we don't really need mm_lock in unregister
> because it's ok to unregister in the middle of the range_begin/end
> critical section (that's definitely not ok for register that's why
> register needs mm_lock). And it's perfectly ok to fail in register().

I think you still need mm_lock (unless I miss something).  What happens
when one callout is scanning mmu_notifier_invalidate_range_start() and
you unlink.  That list next pointer with LIST_POISON1 which is a really
bad address for the processor to track.

Maybe I misunderstood your description.

Thanks,
Robin

WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: Andrea Arcangeli <andrea@qumranet.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>,
	Christoph Lameter <clameter@sgi.com>,
	akpm@linux-foundation.org, Nick Piggin <npiggin@suse.de>,
	Steve Wise <swise@opengridcomputing.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-mm@kvack.org, Kanoj Sarcar <kanojsarcar@yahoo.com>,
	Roland Dreier <rdreier@cisco.com>, Jack Steiner <steiner@sgi.com>,
	linux-kernel@vger.kernel.org, Avi Kivity <avi@qumranet.com>,
	kvm-devel@lists.sourceforge.net, Robin Holt <holt@sgi.com>,
	general@lists.openfabrics.org, Hugh Dickins <hugh@veritas.com>
Subject: Re: [PATCH 1 of 9] Lock the entire mm to prevent any mmu related operation to happen
Date: Fri, 25 Apr 2008 14:25:32 -0500	[thread overview]
Message-ID: <20080425192532.GA19717@sgi.com> (raw)
In-Reply-To: <20080425165639.GA23300@duo.random>

On Fri, Apr 25, 2008 at 06:56:40PM +0200, Andrea Arcangeli wrote:
> Fortunately I figured out we don't really need mm_lock in unregister
> because it's ok to unregister in the middle of the range_begin/end
> critical section (that's definitely not ok for register that's why
> register needs mm_lock). And it's perfectly ok to fail in register().

I think you still need mm_lock (unless I miss something).  What happens
when one callout is scanning mmu_notifier_invalidate_range_start() and
you unlink.  That list next pointer with LIST_POISON1 which is a really
bad address for the processor to track.

Maybe I misunderstood your description.

Thanks,
Robin

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  parent reply	other threads:[~2008-04-25 19:25 UTC|newest]

Thread overview: 125+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-04-08 15:44 [PATCH 0 of 9] mmu notifier #v12 Andrea Arcangeli
2008-04-08 15:44 ` Andrea Arcangeli
2008-04-08 15:44 ` [ofa-general] " Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 1 of 9] Lock the entire mm to prevent any mmu related operation to happen Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-16 16:33   ` Robin Holt
2008-04-16 16:33     ` Robin Holt
2008-04-16 16:33     ` [ofa-general] " Robin Holt
2008-04-16 18:35     ` Christoph Lameter
2008-04-16 18:35       ` Christoph Lameter
2008-04-16 18:35       ` [ofa-general] " Christoph Lameter
2008-04-16 19:02       ` Robin Holt
2008-04-16 19:02         ` Robin Holt
2008-04-16 19:02         ` Robin Holt
2008-04-16 19:15         ` Christoph Lameter
2008-04-16 19:15           ` Christoph Lameter
2008-04-16 19:15           ` [ofa-general] " Christoph Lameter
2008-04-17 11:14           ` Robin Holt
2008-04-17 11:14             ` Robin Holt
2008-04-17 11:14             ` [ofa-general] " Robin Holt
2008-04-17 15:51       ` Andrea Arcangeli
2008-04-17 15:51         ` Andrea Arcangeli
2008-04-17 16:36         ` Robin Holt
2008-04-17 16:36           ` Robin Holt
2008-04-17 17:14           ` Andrea Arcangeli
2008-04-17 17:14             ` Andrea Arcangeli
2008-04-17 17:14             ` Andrea Arcangeli
2008-04-17 17:25             ` Robin Holt
2008-04-17 17:25               ` Robin Holt
2008-04-17 17:25               ` [ofa-general] " Robin Holt
2008-04-17 19:10             ` Christoph Lameter
2008-04-17 19:10               ` Christoph Lameter
2008-04-17 22:16               ` Andrea Arcangeli
2008-04-17 22:16                 ` Andrea Arcangeli
2008-04-17 22:16                 ` [ofa-general] " Andrea Arcangeli
2008-04-22  5:06   ` Rusty Russell
2008-04-22  5:06     ` Rusty Russell
2008-04-22  5:06     ` Rusty Russell
2008-04-25 16:56     ` Andrea Arcangeli
2008-04-25 16:56       ` Andrea Arcangeli
2008-04-25 17:04       ` Andrea Arcangeli
2008-04-25 17:04         ` Andrea Arcangeli
2008-04-25 19:25       ` Robin Holt [this message]
2008-04-25 19:25         ` Robin Holt
2008-04-25 19:25         ` [ofa-general] " Robin Holt
2008-04-26  0:57         ` Andrea Arcangeli
2008-04-26  0:57           ` Andrea Arcangeli
2008-04-26  0:57           ` Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 2 of 9] Core of mmu notifiers Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 16:26   ` Robin Holt
2008-04-08 16:26     ` Robin Holt
2008-04-08 16:26     ` [ofa-general] " Robin Holt
2008-04-08 17:05     ` Andrea Arcangeli
2008-04-08 17:05       ` Andrea Arcangeli
2008-04-14 19:57   ` Christoph Lameter
2008-04-14 19:57     ` Christoph Lameter
2008-04-14 19:57     ` [ofa-general] " Christoph Lameter
2008-04-14 19:59   ` Christoph Lameter
2008-04-14 19:59     ` Christoph Lameter
2008-04-14 19:59     ` Christoph Lameter
2008-04-08 15:44 ` [PATCH 3 of 9] Moves all mmu notifier methods outside the PT lock (first and not last Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-14 19:57   ` Christoph Lameter
2008-04-14 19:57     ` Christoph Lameter
2008-04-14 19:57     ` Christoph Lameter
2008-04-08 15:44 ` [PATCH 4 of 9] Move the tlb flushing into free_pgtables. The conversion of the locks Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 5 of 9] The conversion to a rwsem allows callbacks during rmap traversal Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 6 of 9] We no longer abort unmapping in unmap vmas because we can reschedule while Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 7 of 9] Convert the anon_vma spinlock to a rw semaphore. This allows concurrent Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 8 of 9] XPMEM would have used sys_madvise() except that madvise_dontneed() Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 15:44 ` [PATCH 9 of 9] This patch adds a lock ordering rule to avoid a potential deadlock when Andrea Arcangeli
2008-04-08 15:44   ` Andrea Arcangeli
2008-04-08 15:44   ` [ofa-general] " Andrea Arcangeli
2008-04-08 21:46 ` [PATCH 0 of 9] mmu notifier #v12 Avi Kivity
2008-04-08 21:46   ` Avi Kivity
2008-04-08 21:46   ` [ofa-general] " Avi Kivity
2008-04-08 22:06   ` Andrea Arcangeli
2008-04-08 22:06     ` Andrea Arcangeli
2008-04-08 22:06     ` [ofa-general] " Andrea Arcangeli
2008-04-09 13:17 ` Robin Holt
2008-04-09 13:17   ` Robin Holt
2008-04-09 13:17   ` [ofa-general] " Robin Holt
2008-04-09 14:44   ` Andrea Arcangeli
2008-04-09 14:44     ` Andrea Arcangeli
2008-04-09 14:44     ` [ofa-general] " Andrea Arcangeli
2008-04-09 18:55     ` Robin Holt
2008-04-09 18:55       ` Robin Holt
2008-04-09 18:55       ` [ofa-general] " Robin Holt
2008-04-22  7:20       ` Andrea Arcangeli
2008-04-22  7:20         ` Andrea Arcangeli
2008-04-22  7:20         ` [ofa-general] " Andrea Arcangeli
2008-04-22 12:00         ` Andrea Arcangeli
2008-04-22 12:00           ` Andrea Arcangeli
2008-04-22 12:00           ` [ofa-general] " Andrea Arcangeli
2008-04-22 13:01           ` Robin Holt
2008-04-22 13:01             ` Robin Holt
2008-04-22 13:01             ` [ofa-general] " Robin Holt
2008-04-22 13:21             ` Andrea Arcangeli
2008-04-22 13:21               ` Andrea Arcangeli
2008-04-22 13:21               ` [ofa-general] " Andrea Arcangeli
2008-04-22 13:36               ` Robin Holt
2008-04-22 13:36                 ` Robin Holt
2008-04-22 13:36                 ` [ofa-general] " Robin Holt
2008-04-22 13:48                 ` Andrea Arcangeli
2008-04-22 13:48                   ` Andrea Arcangeli
2008-04-22 13:48                   ` Andrea Arcangeli
2008-04-22 15:26                   ` Robin Holt
2008-04-22 15:26                     ` Robin Holt
2008-04-14 23:09 ` Christoph Lameter
2008-04-14 23:09   ` Christoph Lameter
2008-04-14 23:09   ` [ofa-general] " Christoph Lameter

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