From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Tony Luck <tony.luck@intel.com>,
Xishi Qiu <qiuxishi@huawei.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Minchan Kim <minchan@kernel.org>,
Keping Chen <chenkeping@huawei.com>,
linux-mm@kvack.org, stable@vger.kernel.org,
linux-kernel@vger.kernel.org, Jiang Liu <liuj97@gmail.com>,
David Gibson <david@gibson.dropbear.id.au>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] mm: setup pageblock_order before it's used by sparse
Date: Wed, 18 Jul 2012 17:15:30 +1000 [thread overview]
Message-ID: <1342595730.3669.70.camel@pasglop> (raw)
In-Reply-To: <CAE9FiQVxY9E3L_xmRj10+9D6NVbKaxaAd2oJ6EFe1D+Gy2971w@mail.gmail.com>
On Mon, 2012-07-02 at 20:25 -0700, Yinghai Lu wrote:
> > That means pageblock_order is always set to "MAX_ORDER - 1", not sure
> > whether this is intended. And it has the same issue as IA64 of wasting
> > memory if CONFIG_SPARSE is enabled.
>
> adding BenH, need to know if it is powerpc intended.
>
> >
> > So it would be better to keep function set_pageblock_order(), it will
> > fix the memory wasting on both IA64 and PowerPC.
>
> Should setup pageblock_order as early as possible to avoid confusing.
Hrm, HPAGE_SHIFT is initially 0 because we only know at runtime what
huge page sizes are going to be supported (if any).
The business with pageblock_order is new to me and does look bogus today
indeed. But not a huge deal either. Our MAX_ORDER is typically 9 (64K
pages) or 13 (4K pages) and our standard huge page size is generally 16M
so there isn't a big difference here.
Still, maybe something worth looking into...
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Jiang Liu <jiang.liu@huawei.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Tony Luck <tony.luck@intel.com>,
Xishi Qiu <qiuxishi@huawei.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Minchan Kim <minchan@kernel.org>,
Keping Chen <chenkeping@huawei.com>,
linux-mm@kvack.org, stable@vger.kernel.org,
linux-kernel@vger.kernel.org, Jiang Liu <liuj97@gmail.com>,
David Gibson <david@gibson.dropbear.id.au>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] mm: setup pageblock_order before it's used by sparse
Date: Wed, 18 Jul 2012 17:15:30 +1000 [thread overview]
Message-ID: <1342595730.3669.70.camel@pasglop> (raw)
In-Reply-To: <CAE9FiQVxY9E3L_xmRj10+9D6NVbKaxaAd2oJ6EFe1D+Gy2971w@mail.gmail.com>
On Mon, 2012-07-02 at 20:25 -0700, Yinghai Lu wrote:
> > That means pageblock_order is always set to "MAX_ORDER - 1", not sure
> > whether this is intended. And it has the same issue as IA64 of wasting
> > memory if CONFIG_SPARSE is enabled.
>
> adding BenH, need to know if it is powerpc intended.
>
> >
> > So it would be better to keep function set_pageblock_order(), it will
> > fix the memory wasting on both IA64 and PowerPC.
>
> Should setup pageblock_order as early as possible to avoid confusing.
Hrm, HPAGE_SHIFT is initially 0 because we only know at runtime what
huge page sizes are going to be supported (if any).
The business with pageblock_order is new to me and does look bogus today
indeed. But not a huge deal either. Our MAX_ORDER is typically 9 (64K
pages) or 13 (4K pages) and our standard huge page size is generally 16M
so there isn't a big difference here.
Still, maybe something worth looking into...
Cheers,
Ben.
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WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Tony Luck <tony.luck@intel.com>, Jiang Liu <jiang.liu@huawei.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, Minchan Kim <minchan@kernel.org>,
Keping Chen <chenkeping@huawei.com>, Mel Gorman <mgorman@suse.de>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
David Rientjes <rientjes@google.com>,
Xishi Qiu <qiuxishi@huawei.com>,
Andrew Morton <akpm@linux-foundation.org>,
David Gibson <david@gibson.dropbear.id.au>,
linuxppc-dev@lists.ozlabs.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Jiang Liu <liuj97@gmail.com>
Subject: Re: [PATCH] mm: setup pageblock_order before it's used by sparse
Date: Wed, 18 Jul 2012 17:15:30 +1000 [thread overview]
Message-ID: <1342595730.3669.70.camel@pasglop> (raw)
In-Reply-To: <CAE9FiQVxY9E3L_xmRj10+9D6NVbKaxaAd2oJ6EFe1D+Gy2971w@mail.gmail.com>
On Mon, 2012-07-02 at 20:25 -0700, Yinghai Lu wrote:
> > That means pageblock_order is always set to "MAX_ORDER - 1", not sure
> > whether this is intended. And it has the same issue as IA64 of wasting
> > memory if CONFIG_SPARSE is enabled.
>
> adding BenH, need to know if it is powerpc intended.
>
> >
> > So it would be better to keep function set_pageblock_order(), it will
> > fix the memory wasting on both IA64 and PowerPC.
>
> Should setup pageblock_order as early as possible to avoid confusing.
Hrm, HPAGE_SHIFT is initially 0 because we only know at runtime what
huge page sizes are going to be supported (if any).
The business with pageblock_order is new to me and does look bogus today
indeed. But not a huge deal either. Our MAX_ORDER is typically 9 (64K
pages) or 13 (4K pages) and our standard huge page size is generally 16M
so there isn't a big difference here.
Still, maybe something worth looking into...
Cheers,
Ben.
next prev parent reply other threads:[~2012-07-18 7:16 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-30 9:07 [PATCH] mm: setup pageblock_order before it's used by sparse Jiang Liu
2012-06-30 9:07 ` Jiang Liu
2012-06-30 20:15 ` Yinghai Lu
2012-07-02 2:01 ` Jiang Liu
2012-07-02 2:01 ` Jiang Liu
2012-07-02 2:01 ` Jiang Liu
2012-07-02 20:43 ` Yinghai Lu
2012-07-03 2:54 ` Jiang Liu
2012-07-03 2:54 ` Jiang Liu
2012-07-03 2:54 ` Jiang Liu
2012-07-03 2:54 ` Jiang Liu
2012-07-03 3:25 ` Yinghai Lu
2012-07-03 3:25 ` Yinghai Lu
2012-07-03 3:25 ` Yinghai Lu
2012-07-03 3:25 ` Yinghai Lu
2012-07-03 3:29 ` Jiang Liu
2012-07-03 3:29 ` Jiang Liu
2012-07-03 3:29 ` Jiang Liu
2012-07-18 7:17 ` Benjamin Herrenschmidt
2012-07-18 7:17 ` Benjamin Herrenschmidt
2012-07-18 7:17 ` Benjamin Herrenschmidt
2012-07-18 7:15 ` Benjamin Herrenschmidt [this message]
2012-07-18 7:15 ` Benjamin Herrenschmidt
2012-07-18 7:15 ` Benjamin Herrenschmidt
2012-06-30 20:46 ` Greg KH
2012-06-30 20:46 ` Greg KH
2012-07-02 12:41 ` Mel Gorman
2012-07-02 12:41 ` Mel Gorman
2012-07-03 21:07 ` Andrew Morton
2012-07-03 21:07 ` Andrew Morton
2012-07-04 1:40 ` Jiang Liu
2012-07-04 1:40 ` Jiang Liu
2012-07-04 9:20 ` Mel Gorman
2012-07-04 9:20 ` Mel Gorman
2012-07-06 1:00 ` Yinghai Lu
2012-07-06 1:00 ` Yinghai Lu
2012-07-06 1:24 ` Benjamin Herrenschmidt
2012-07-06 1:24 ` Benjamin Herrenschmidt
2012-07-17 9:31 ` Jiang Liu
2012-07-17 9:31 ` Jiang Liu
2012-07-18 7:01 ` Benjamin Herrenschmidt
2012-07-18 7:01 ` Benjamin Herrenschmidt
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