From: Christoph Lameter <clameter@sgi.com>
To: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"nickpiggin@yahoo.com.au" <nickpiggin@yahoo.com.au>,
"Lee.Schermerhorn@hp.com" <Lee.Schermerhorn@hp.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Martin J. Bligh" <mbligh@google.com>
Subject: Re: [RFC][PATCH] overwride page->mapping [0/3] intro
Date: Wed, 12 Sep 2007 12:10:12 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0709121207400.1934@schroedinger.engr.sgi.com> (raw)
In-Reply-To: <46E7A666.7080409@linux.vnet.ibm.com>
On Wed, 12 Sep 2007, Balbir Singh wrote:
> We discussed the struct page size issue at VM summit. If I remember
> correctly, Linus suggested that we consider using pfn's instead of
> pointers for pointer members in struct page.
How would that save any memory? On a system with 16TB memory and 4k page
size you have at least 4 billion pfns which is the max that an unsigned
int can handle. If the virtual address space is sparse or larger (like on
IA64) then you need to use an int with more than 32 bit anyways.
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next prev parent reply other threads:[~2007-09-12 19:10 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-12 2:43 KAMEZAWA Hiroyuki
2007-09-12 2:45 ` [RFC][PATCH] overwride page->mapping [1/3] cleanup KAMEZAWA Hiroyuki
2007-09-12 2:47 ` [RFC][PATCH] overwride page->mapping [2/3] page_mapping_info KAMEZAWA Hiroyuki
2007-09-12 2:48 ` [RFC][PATCH] override page->mapping [3/3] mlock counter per page KAMEZAWA Hiroyuki
2007-09-12 8:42 ` [RFC][PATCH] overwride page->mapping [0/3] intro Balbir Singh
2007-09-12 13:28 ` KAMEZAWA Hiroyuki
2007-09-12 19:10 ` Christoph Lameter [this message]
2007-09-12 19:12 ` Martin Bligh
2007-09-12 19:17 ` Christoph Lameter
2007-09-13 0:32 ` KAMEZAWA Hiroyuki
2007-09-13 1:05 ` Christoph Lameter
2007-09-13 1:27 ` KAMEZAWA Hiroyuki
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