From: Shaohua Li <shaohua.li@intel.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>, Simon Kirby <sim@hostway.ca>,
Dave Hansen <dave@linux.vnet.ibm.com>,
linux-mm <linux-mm@kvack.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] mm: kswapd: Stop high-order balancing when any suitable zone is balanced
Date: Wed, 01 Dec 2010 16:24:26 +0800 [thread overview]
Message-ID: <1291191866.12777.82.camel@sli10-conroe> (raw)
In-Reply-To: <20101201164647.ABD7.A69D9226@jp.fujitsu.com>
On Wed, 2010-12-01 at 15:52 +0800, KOSAKI Motohiro wrote:
> > > > > we can't make
> > > > > perfect VM heuristics obviously, then we need to compare pros/cons.
> > > > if you don't care about small system, let's consider a NORMAL i386
> > > > system with 896m normal zone, and 896M*3 high zone. normal zone will
> > > > quickly exhaust by high order high zone allocation, leave a latter
> > > > allocation which does need normal zone fail.
> > >
> > > Not happen. slab don't allocate from highmem and page cache allocation
> > > is always using order-0. When happen high order high zone allocation?
> > ok, thanks, I missed this. then how about a x86_64 box with 896M DMA32
> > and 896*3M NORMAL? some pci devices can only dma to DMA32 zone.
>
> First, DMA32 is 4GB. Second, modern high end system don't use 32bit PCI
> device. Third, while we are thinking desktop users, 4GB is not small
> room. nowadays, typical desktop have only 2GB or 4GB memory.
DMA32 isn't 4G, because there is hole under 4G for PCI bars. I don't
think 32 bit PCI device is rare too. But anyway, if you insist this
isn't a big issue, I'm ok.
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next prev parent reply other threads:[~2010-12-01 8:24 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-30 17:15 [RFC PATCH 0/3] Prevent kswapd dumping excessive amounts of memory in response to high-order allocations Mel Gorman
2010-11-30 17:15 ` [PATCH 1/3] mm: kswapd: Stop high-order balancing when any suitable zone is balanced Mel Gorman
2010-12-01 2:13 ` Shaohua Li
2010-12-01 2:23 ` KOSAKI Motohiro
2010-12-01 2:47 ` Shaohua Li
2010-12-01 2:59 ` KOSAKI Motohiro
2010-12-01 3:20 ` Shaohua Li
2010-12-01 3:28 ` KOSAKI Motohiro
2010-12-01 7:40 ` Shaohua Li
2010-12-01 7:52 ` KOSAKI Motohiro
2010-12-01 8:24 ` Shaohua Li [this message]
2010-12-01 11:07 ` Mel Gorman
2010-11-30 17:15 ` [PATCH 2/3] mm: kswapd: Use the order that kswapd was reclaiming at for sleeping_prematurely() Mel Gorman
2010-11-30 17:15 ` [PATCH 3/3] mm: kswapd: Keep kswapd awake for high-order allocations until a percentage of the node is balanced Mel Gorman
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