From: Mel Gorman <mgorman@suse.de>
To: Pavel Machek <pavel@ucw.cz>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux-Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>, Neil Brown <neilb@suse.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 00/13] Swap-over-NBD without deadlocking
Date: Thu, 28 Apr 2011 14:42:35 +0100 [thread overview]
Message-ID: <20110428134235.GW4658@suse.de> (raw)
In-Reply-To: <20110428133154.GA8572@ucw.cz>
On Thu, Apr 28, 2011 at 03:31:55PM +0200, Pavel Machek wrote:
> Hi!
>
>
> > For testing swap-over-NBD, a machine was booted with 2G of RAM with a
> > swapfile backed by NBD. 16*NUM_CPU processes were started that create
> > anonymous memory mappings and read them linearly in a loop. The total
> > size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under
> > memory pressure. Without the patches, the machine locks up within
> > minutes and runs to completion with them applied.
> >
> > Comments?
>
> Nice!
>
> It is easy to see why swapping needs these fixes, but... dirty memory
> writeout is used for memory clearing, too. Are same changes neccessary
> to make that safe?
>
Dirty page limiting covers the MAP_SHARED cases and are already
throttled approprately.
> (Perhaps raise 'max dirty %' for testing?)
Stress testing passed for dirty ratios of 40% at least. Maybe it would
cause issues when raised to nearly 100% but I don't think that is a
particularly interesting use case.
--
Mel Gorman
SUSE Labs
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Pavel Machek <pavel@ucw.cz>
Cc: Linux-MM <linux-mm@kvack.org>,
Linux-Netdev <netdev@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
David Miller <davem@davemloft.net>, Neil Brown <neilb@suse.de>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH 00/13] Swap-over-NBD without deadlocking
Date: Thu, 28 Apr 2011 14:42:35 +0100 [thread overview]
Message-ID: <20110428134235.GW4658@suse.de> (raw)
In-Reply-To: <20110428133154.GA8572@ucw.cz>
On Thu, Apr 28, 2011 at 03:31:55PM +0200, Pavel Machek wrote:
> Hi!
>
>
> > For testing swap-over-NBD, a machine was booted with 2G of RAM with a
> > swapfile backed by NBD. 16*NUM_CPU processes were started that create
> > anonymous memory mappings and read them linearly in a loop. The total
> > size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under
> > memory pressure. Without the patches, the machine locks up within
> > minutes and runs to completion with them applied.
> >
> > Comments?
>
> Nice!
>
> It is easy to see why swapping needs these fixes, but... dirty memory
> writeout is used for memory clearing, too. Are same changes neccessary
> to make that safe?
>
Dirty page limiting covers the MAP_SHARED cases and are already
throttled approprately.
> (Perhaps raise 'max dirty %' for testing?)
Stress testing passed for dirty ratios of 40% at least. Maybe it would
cause issues when raised to nearly 100% but I don't think that is a
particularly interesting use case.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2011-04-28 13:42 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-26 7:36 [PATCH 00/13] Swap-over-NBD without deadlocking Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 01/13] mm: Serialize access to min_free_kbytes Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 02/13] mm: sl[au]b: Add knowledge of PFMEMALLOC reserve pages Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 11:15 ` NeilBrown
2011-04-26 11:15 ` NeilBrown
2011-04-26 11:33 ` Mel Gorman
2011-04-26 11:33 ` Mel Gorman
2011-04-26 12:05 ` NeilBrown
2011-04-26 12:05 ` NeilBrown
2011-04-26 11:37 ` NeilBrown
2011-04-26 11:37 ` NeilBrown
2011-04-26 13:59 ` Mel Gorman
2011-04-26 13:59 ` Mel Gorman
2011-04-27 23:21 ` NeilBrown
2011-04-27 23:21 ` NeilBrown
2011-04-28 9:46 ` Mel Gorman
2011-04-28 9:46 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 03/13] mm: Introduce __GFP_MEMALLOC to allow access to emergency reserves Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 9:49 ` NeilBrown
2011-04-26 9:49 ` NeilBrown
2011-04-26 10:36 ` Mel Gorman
2011-04-26 10:36 ` Mel Gorman
2011-04-26 10:53 ` NeilBrown
2011-04-26 10:53 ` NeilBrown
2011-04-26 14:00 ` Mel Gorman
2011-04-26 14:00 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 04/13] mm: allow PF_MEMALLOC from softirq context Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 05/13] mm: Ignore mempolicies when using ALLOC_NO_WATERMARK Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 06/13] net: Introduce sk_allocation() to allow addition of GFP flags depending on the individual socket Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 07/13] netvm: Allow the use of __GFP_MEMALLOC by specific sockets Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 08/13] netvm: Allow skb allocation to use PFMEMALLOC reserves Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 09/13] netvm: Set PF_MEMALLOC as appropriate during SKB processing Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 12:21 ` NeilBrown
2011-04-26 12:21 ` NeilBrown
2011-04-26 14:10 ` Mel Gorman
2011-04-26 14:10 ` Mel Gorman
2011-04-26 23:22 ` NeilBrown
2011-04-26 23:22 ` NeilBrown
2011-04-26 7:36 ` [PATCH 10/13] mm: Micro-optimise slab to avoid a function call Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 11/13] nbd: Set SOCK_MEMALLOC for access to PFMEMALLOC reserves Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 12/13] mm: Throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 12:30 ` NeilBrown
2011-04-26 12:30 ` NeilBrown
2011-04-26 14:26 ` Mel Gorman
2011-04-26 14:26 ` Mel Gorman
2011-04-26 23:18 ` NeilBrown
2011-04-26 23:18 ` NeilBrown
2011-04-27 8:36 ` Mel Gorman
2011-04-27 8:36 ` Mel Gorman
2011-04-26 7:36 ` [PATCH 13/13] mm: Account for the number of times direct reclaimers get throttled Mel Gorman
2011-04-26 7:36 ` Mel Gorman
2011-04-26 12:35 ` NeilBrown
2011-04-26 12:35 ` NeilBrown
2011-04-26 14:26 ` Mel Gorman
2011-04-26 14:26 ` Mel Gorman
2011-04-26 14:23 ` [PATCH 00/13] Swap-over-NBD without deadlocking Peter Zijlstra
2011-04-26 14:23 ` Peter Zijlstra
2011-04-26 14:46 ` Mel Gorman
2011-04-26 14:46 ` Mel Gorman
2011-04-26 14:50 ` Peter Zijlstra
2011-04-26 14:50 ` Peter Zijlstra
2011-04-27 8:43 ` Mel Gorman
2011-04-27 8:43 ` Mel Gorman
2011-04-28 13:31 ` Pavel Machek
2011-04-28 13:31 ` Pavel Machek
2011-04-28 13:42 ` Mel Gorman [this message]
2011-04-28 13:42 ` Mel Gorman
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