Re: [RFC] Replace the watermark-related union in struct zone with awatermark[] array V2

Dave Hansen
2009-05-12T15:06:32Z

On Tue, 2009-05-12 at 15:13 +0100, Mel Gorman wrote:
> Changelog since V1
> o Use N_wmark_pages accessors instead of array accesses
>
> Patch page-allocator-use-allocation-flags-as-an-index-to-the-zone-watermark
> from -mm added a union to struct zone where the watermarks could be accessed
> with either zone->pages_* or a pages_mark array. The concern was that this
> aliasing caused more confusion that it helped.
>
> This patch replaces the union with a watermark array that is indexed with
> WMARK_* defines accessed via helpers. All call sites that use zone->pages_*
> are updated to use the helpers for accessing the values and the array
> offsets for setting.
>
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
> ---
> Documentation/sysctl/vm.txt | 11 ++++++-----
> Documentation/vm/balance | 18 +++++++++---------
> arch/m32r/mm/discontig.c | 6 +++---
> include/linux/mmzone.h | 20 ++++++++++++++------
> mm/page_alloc.c | 41 +++++++++++++++++++++--------------------
> mm/vmscan.c | 39 +++++++++++++++++++++------------------
> mm/vmstat.c | 6 +++---
> 7 files changed, 77 insertions(+), 64 deletions(-)

Looks nice. It net adds a few lines of code, but that's mostly from the
#defines and not added complexity or lots of line wrapping.

Ackedf-by: Dave Hansen <dave@linux.vnet.ibm.com>

-- Dave