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Message-ID: <Pine.LNX.4.64.0704191208340.12936@schroedinger.engr.sgi.com>
Date: Thu, 19 Apr 2007 12:10:34 -0700 (PDT)
From: Christoph Lameter <clameter@....com>
To: Adam Litke <aglitke@...il.com>
cc: linux-kernel@...r.kernel.org,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Nick Piggin <nickpiggin@...oo.com.au>, Andi Kleen <ak@...e.de>,
Paul Jackson <pj@....com>, Dave Chinner <dgc@....com>
Subject: Re: [RFC 4/8] Enhance fallback functions in libs to support higher
order pages
On Thu, 19 Apr 2007, Adam Litke wrote:
> On 4/19/07, Christoph Lameter <clameter@....com> wrote:
> > @@ -331,11 +331,15 @@ int simple_prepare_write(struct file *fi
> > unsigned from, unsigned to)
> > {
> > if (!PageUptodate(page)) {
> > - if (to - from != PAGE_CACHE_SIZE) {
> > + if (to - from != page_cache_size(file->f_mapping)) {
>
> Where do you introduce page_cache_size()? Is this added by a
> different set of patches I should have applied first?
Yuck. Missed that one in the control file. Insert this patch before this
one.
Variable Order Page Cache: Add functions to establish sizes
We use the macros PAGE_CACHE_SIZE PAGE_CACHE_SHIFT PAGE_CACHE_MASK
and PAGE_CACHE_ALIGN in various places in the kernel. These are now
the base page size but we do not have a means to calculating these
values for higher order pages.
Provide these functions. An address_space pointer must be passed
to them.
New function Related base page constant
---------------------------------------------------
page_cache_shift(a) PAGE_CACHE_SHIFT
page_cache_size(a) PAGE_CACHE_SIZE
page_cache_mask(a) PAGE_CACHE_MASK
page_cache_align(addr,a) PAGE_CACHE_ALIGN(addr)
Signed-off-by: Christoph Lameter <clameter@....com>
---
include/linux/pagemap.h | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
Index: linux-2.6.21-rc7/include/linux/pagemap.h
===================================================================
--- linux-2.6.21-rc7.orig/include/linux/pagemap.h 2007-04-18 23:01:09.000000000 -0700
+++ linux-2.6.21-rc7/include/linux/pagemap.h 2007-04-18 23:03:32.000000000 -0700
@@ -49,6 +49,27 @@ static inline void mapping_set_gfp_mask(
#define PAGE_CACHE_MASK PAGE_MASK
#define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
+static inline int page_cache_shift(struct address_space *a)
+{
+ return a->order + PAGE_CACHE_SHIFT;
+}
+
+static inline unsigned long page_cache_size(struct address_space *a)
+{
+ return PAGE_CACHE_SIZE << a->order;
+}
+
+static inline unsigned long page_cache_mask(struct address_space *a)
+{
+ return PAGE_CACHE_MASK << a->order;
+}
+
+static inline unsigned long page_cache_align(unsigned long addr,
+ struct address_space *a)
+{
+ return (((addr) + page_cache_size(a) - 1) & page_cache_mask(a));
+}
+
#define page_cache_get(page) get_page(page)
#define page_cache_release(page) put_page(page)
void release_pages(struct page **pages, int nr, int cold);
-
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