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From: Robin Holt <holt@sgi.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>,
	Andrea Arcangeli <andrea@qumranet.com>, Robin Holt <holt@sgi.com>,
	Avi Kivity <avi@qumranet.com>, Izik Eidus <izike@qumranet.com>,
	Nick Piggin <npiggin@suse.de>,
	kvm-devel@lists.sourceforge.net,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	daniel.blueman@quadrics.com, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch 1/6] mmu_notifier: Core code
Date: Wed, 30 Jan 2008 16:20:35 -0600	[thread overview]
Message-ID: <20080130222035.GX26420@sgi.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0801301116510.27491@schroedinger.engr.sgi.com>

On Wed, Jan 30, 2008 at 11:19:28AM -0800, Christoph Lameter wrote:
> On Wed, 30 Jan 2008, Jack Steiner wrote:
> 
> > Moving to a different lock solves the problem.
> 
> Well it gets us back to the issue why we removed the lock. As Robin said 
> before: If its global then we can have a huge number of tasks contending 
> for the lock on startup of a process with a large number of ranks. The 
> reason to go to mmap_sem was that it was placed in the mm_struct and so we 
> would just have a couple of contentions per mm_struct.
> 
> I'll be looking for some other way to do this.

I think Andrea's original concept of the lock in the mmu_notifier_head
structure was the best.  I agree with him that it should be a spinlock
instead of the rw_lock.

Thanks,
Robin

WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt-sJ/iWh9BUns@public.gmane.org>
To: Christoph Lameter <clameter-sJ/iWh9BUns@public.gmane.org>
Cc: Nick Piggin <npiggin-l3A5Bk7waGM@public.gmane.org>,
	Andrea Arcangeli <andrea-atKUWr5tajBWk0Htik3J/w@public.gmane.org>,
	Peter Zijlstra
	<a.p.zijlstra-/NLkJaSkS4VmR6Xm/wNWPw@public.gmane.org>,
	linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org,
	Benjamin Herrenschmidt
	<benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>,
	Jack Steiner <steiner-sJ/iWh9BUns@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>,
	kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	daniel.blueman-xqY44rlHlBpWk0Htik3J/w@public.gmane.org,
	Robin Holt <holt-sJ/iWh9BUns@public.gmane.org>,
	Hugh Dickins <hugh-DTz5qymZ9yRBDgjK7y7TUQ@public.gmane.org>
Subject: Re: [patch 1/6] mmu_notifier: Core code
Date: Wed, 30 Jan 2008 16:20:35 -0600	[thread overview]
Message-ID: <20080130222035.GX26420@sgi.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0801301116510.27491-RYO/mD75kfhx2SFC9UQUAuF7EQX82lMiAL8bYrjMMd8@public.gmane.org>

On Wed, Jan 30, 2008 at 11:19:28AM -0800, Christoph Lameter wrote:
> On Wed, 30 Jan 2008, Jack Steiner wrote:
> 
> > Moving to a different lock solves the problem.
> 
> Well it gets us back to the issue why we removed the lock. As Robin said 
> before: If its global then we can have a huge number of tasks contending 
> for the lock on startup of a process with a large number of ranks. The 
> reason to go to mmap_sem was that it was placed in the mm_struct and so we 
> would just have a couple of contentions per mm_struct.
> 
> I'll be looking for some other way to do this.

I think Andrea's original concept of the lock in the mmu_notifier_head
structure was the best.  I agree with him that it should be a spinlock
instead of the rw_lock.

Thanks,
Robin

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WARNING: multiple messages have this Message-ID (diff)
From: Robin Holt <holt@sgi.com>
To: Christoph Lameter <clameter@sgi.com>
Cc: Jack Steiner <steiner@sgi.com>,
	Andrea Arcangeli <andrea@qumranet.com>, Robin Holt <holt@sgi.com>,
	Avi Kivity <avi@qumranet.com>, Izik Eidus <izike@qumranet.com>,
	Nick Piggin <npiggin@suse.de>,
	kvm-devel@lists.sourceforge.net,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	daniel.blueman@quadrics.com, Hugh Dickins <hugh@veritas.com>
Subject: Re: [patch 1/6] mmu_notifier: Core code
Date: Wed, 30 Jan 2008 16:20:35 -0600	[thread overview]
Message-ID: <20080130222035.GX26420@sgi.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0801301116510.27491@schroedinger.engr.sgi.com>

On Wed, Jan 30, 2008 at 11:19:28AM -0800, Christoph Lameter wrote:
> On Wed, 30 Jan 2008, Jack Steiner wrote:
> 
> > Moving to a different lock solves the problem.
> 
> Well it gets us back to the issue why we removed the lock. As Robin said 
> before: If its global then we can have a huge number of tasks contending 
> for the lock on startup of a process with a large number of ranks. The 
> reason to go to mmap_sem was that it was placed in the mm_struct and so we 
> would just have a couple of contentions per mm_struct.
> 
> I'll be looking for some other way to do this.

I think Andrea's original concept of the lock in the mmu_notifier_head
structure was the best.  I agree with him that it should be a spinlock
instead of the rw_lock.

Thanks,
Robin

--
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  reply	other threads:[~2008-01-30 22:20 UTC|newest]

Thread overview: 123+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-30  2:29 [patch 0/6] [RFC] MMU Notifiers V3 Christoph Lameter
2008-01-30  2:29 ` Christoph Lameter
2008-01-30  2:29 ` [patch 1/6] mmu_notifier: Core code Christoph Lameter
2008-01-30  2:29   ` Christoph Lameter
2008-01-30 15:37   ` Andrea Arcangeli
2008-01-30 15:37     ` Andrea Arcangeli
2008-01-30 15:37     ` Andrea Arcangeli
2008-01-30 15:53     ` Jack Steiner
2008-01-30 15:53       ` Jack Steiner
2008-01-30 15:53       ` Jack Steiner
2008-01-30 16:38       ` Andrea Arcangeli
2008-01-30 16:38         ` Andrea Arcangeli
2008-01-30 16:38         ` Andrea Arcangeli
2008-01-30 19:19       ` Christoph Lameter
2008-01-30 19:19         ` Christoph Lameter
2008-01-30 19:19         ` Christoph Lameter
2008-01-30 22:20         ` Robin Holt [this message]
2008-01-30 22:20           ` Robin Holt
2008-01-30 22:20           ` Robin Holt
2008-01-30 23:38           ` Andrea Arcangeli
2008-01-30 23:38             ` Andrea Arcangeli
2008-01-30 23:38             ` Andrea Arcangeli
2008-01-30 23:55             ` Christoph Lameter
2008-01-30 23:55               ` Christoph Lameter
2008-01-31  0:12               ` [kvm-devel] " Andrea Arcangeli
2008-01-31  0:12                 ` Andrea Arcangeli
2008-01-31  0:12                 ` Andrea Arcangeli
2008-01-31  1:27                 ` [kvm-devel] " Christoph Lameter
2008-01-31  1:27                   ` Christoph Lameter
2008-01-31  1:27                   ` Christoph Lameter
2008-01-30 17:10     ` Peter Zijlstra
2008-01-30 17:10       ` Peter Zijlstra
2008-01-30 19:28       ` Christoph Lameter
2008-01-30 19:28         ` Christoph Lameter
2008-01-30 19:28         ` Christoph Lameter
2008-01-30 18:02   ` Robin Holt
2008-01-30 18:02     ` Robin Holt
2008-01-30 18:02     ` Robin Holt
2008-01-30 19:08     ` Christoph Lameter
2008-01-30 19:08       ` Christoph Lameter
2008-01-30 19:08       ` Christoph Lameter
2008-01-30 19:14     ` Christoph Lameter
2008-01-30 19:14       ` Christoph Lameter
2008-01-30 19:14       ` Christoph Lameter
2008-01-30  2:29 ` [patch 2/6] mmu_notifier: Callbacks to invalidate address ranges Christoph Lameter
2008-01-30  2:29   ` Christoph Lameter
2008-01-30  2:29 ` [patch 3/6] mmu_notifier: invalidate_page callbacks for subsystems with rmap Christoph Lameter
2008-01-30  2:29   ` Christoph Lameter
2008-01-30 18:03   ` Robin Holt
2008-01-30 18:03     ` Robin Holt
2008-01-30 18:03     ` Robin Holt
2008-01-30  2:29 ` [patch 4/6] MMU notifier: invalidate_page callbacks using Linux rmaps Christoph Lameter
2008-01-30  2:29   ` Christoph Lameter
2008-01-30  2:29 ` [patch 5/6] mmu_notifier: Callbacks for xip_filemap.c Christoph Lameter
2008-01-30  2:29   ` Christoph Lameter
2008-01-30  2:29 ` [patch 6/6] mmu_notifier: Add invalidate_all() Christoph Lameter
2008-01-30  2:29   ` Christoph Lameter
  -- strict thread matches above, loose matches on Subject: below --
2008-02-15  6:48 [patch 0/6] MMU Notifiers V7 Christoph Lameter
2008-02-15  6:49 ` [patch 1/6] mmu_notifier: Core code Christoph Lameter
2008-02-15  6:49   ` Christoph Lameter
2008-02-16  3:37   ` Andrew Morton
2008-02-16  3:37     ` Andrew Morton
2008-02-16  8:45     ` Avi Kivity
2008-02-16  8:45       ` Avi Kivity
2008-02-16  8:45       ` Avi Kivity
2008-02-16  8:56       ` Andrew Morton
2008-02-16  8:56         ` Andrew Morton
2008-02-16  9:21         ` Avi Kivity
2008-02-16  9:21           ` Avi Kivity
2008-02-16  9:21           ` Avi Kivity
2008-02-16 10:41     ` Brice Goglin
2008-02-16 10:41       ` Brice Goglin
2008-02-16 10:58       ` Andrew Morton
2008-02-16 10:58         ` Andrew Morton
2008-02-16 19:31         ` Christoph Lameter
2008-02-16 19:31           ` Christoph Lameter
2008-02-16 19:21     ` Christoph Lameter
2008-02-16 19:21       ` Christoph Lameter
2008-02-17  3:01       ` Andrea Arcangeli
2008-02-17  3:01         ` Andrea Arcangeli
2008-02-17 12:24         ` Robin Holt
2008-02-17 12:24           ` Robin Holt
2008-02-17 12:24           ` Robin Holt
2008-02-17  5:04     ` Doug Maxey
2008-02-17  5:04       ` Doug Maxey
2008-02-17  5:04       ` Doug Maxey
2008-02-18 22:33   ` Roland Dreier
2008-02-18 22:33     ` Roland Dreier
2008-02-08 22:06 [patch 0/6] MMU Notifiers V6 Christoph Lameter
2008-02-08 22:06 ` [patch 1/6] mmu_notifier: Core code Christoph Lameter
2008-02-08 22:06   ` Christoph Lameter
2008-01-28 20:28 [patch 0/6] [RFC] MMU Notifiers V2 Christoph Lameter
2008-01-28 20:28 ` [patch 1/6] mmu_notifier: Core code Christoph Lameter
2008-01-28 20:28   ` Christoph Lameter
2008-01-28 22:06   ` Christoph Lameter
2008-01-28 22:06     ` Christoph Lameter
2008-01-28 22:06     ` Christoph Lameter
2008-01-29  0:05   ` Robin Holt
2008-01-29  0:05     ` Robin Holt
2008-01-29  0:05     ` Robin Holt
2008-01-29  1:19     ` Christoph Lameter
2008-01-29  1:19       ` Christoph Lameter
2008-01-29  1:19       ` Christoph Lameter
2008-01-29 13:59   ` Andrea Arcangeli
2008-01-29 13:59     ` Andrea Arcangeli
2008-01-29 13:59     ` Andrea Arcangeli
2008-01-29 14:34     ` Andrea Arcangeli
2008-01-29 14:34       ` Andrea Arcangeli
2008-01-29 14:34       ` Andrea Arcangeli
2008-01-29 19:49     ` Christoph Lameter
2008-01-29 19:49       ` Christoph Lameter
2008-01-29 19:49       ` Christoph Lameter
2008-01-29 20:41       ` Avi Kivity
2008-01-29 20:41         ` Avi Kivity
2008-01-29 20:41         ` Avi Kivity
2008-01-29 16:07   ` Robin Holt
2008-01-29 16:07     ` Robin Holt
2008-01-29 16:07     ` Robin Holt
2008-02-05 18:05   ` Andy Whitcroft
2008-02-05 18:05     ` Andy Whitcroft
2008-02-05 18:05     ` Andy Whitcroft
2008-02-05 18:17     ` Peter Zijlstra
2008-02-05 18:17       ` Peter Zijlstra
2008-02-05 18:19     ` Christoph Lameter
2008-02-05 18:19       ` Christoph Lameter
2008-02-05 18:19       ` Christoph Lameter

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