Re: [patch 0/9] Page flags V3: Cleanup and reorg

Re: [patch 0/9] Page flags V3: Cleanup and reorg

[Andrew Morton]

On Fri, 07 Mar 2008 16:18:50 -0800 Christoph Lameter <clameter@sgi.com> wrote:

> A set of patches that attempts to improve page flag handling.

First darn thing I tried was i386 allnoconfig and it goes splat.

In file included from include/linux/mm.h:192,
                 from kernel/bounds.c:8:
include/linux/page-flags.h: In function 'PageHighMem':
include/linux/page-flags.h:180: error: implicit declaration of function 'page_zone'

There's also a parenthesis mismatch so it looks like it was neither
compile-time nor runtime tested on i386.  Sorry, but I don't have the time
to be the first one to try this out.


To fix this page-flags.h needs to include mm.h, but mm.h includes
page-flags.h.  Making PageHighMem a macro would be the expedient fix.



--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [patch 0/9] Page flags V3: Cleanup and reorg

[Andrew Morton]

On Tue, 18 Mar 2008 11:19:57 -0700 Christoph Lameter <clameter@sgi.com> wrote:

> A set of patches that attempts to improve page flag handling.

sh allmodconfig blows up with various unsatisfied link-time references to
swapper_space.

this:

--- a/include/linux/mm.h~a
+++ a/include/linux/mm.h
@@ -605,9 +605,12 @@ static inline struct address_space *page
 	struct address_space *mapping = page->mapping;
 
 	VM_BUG_ON(PageSlab(page));
+#ifdef CONFIG_SWAP
 	if (unlikely(PageSwapCache(page)))
 		mapping = &swapper_space;
-	else if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
+	else
+#endif
+	if (unlikely((unsigned long)mapping & PAGE_MAPPING_ANON))
 		mapping = NULL;
 	return mapping;
 }
_

fixes it, but it shouldn't, unless it's a cimpiler bug.  Could you
investigate please, check that we're not adding unintended code bloat for
some reason?

http://userweb.kernel.org/~akpm/cross-compilers/ has the toolchain.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

Re: [patch 0/9] Page flags V3: Cleanup and reorg

[Christoph Lameter]

Ping? Is this okay Dave?

On Thu, 3 Apr 2008, Christoph Lameter wrote:

> On Wed, 2 Apr 2008, David Miller wrote:
> 
> > No this won't work, see PG_dcache_cpu_shift in arch/sparc64/mm/init.c,
> > the code currently statically puts the cpu number of the the cpu which
> > potentially dirtied the page in the D-cache at bit 32 of the page
> > flags and onwards.
> 
> That looks fine to me. If we use less than 32 page flags then bits 32 to 
> the beginning of the zone field are still available.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>