diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2013-02-22 16:34:32 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2013-02-23 17:50:17 -0800 |
| commit | 75980e97daccfc6babbac7e180ff118537955f5d (patch) | |
| tree | b5721bae11eab21a8ee7c2ba4c7f153a59766dd6 /include/linux/page-flags-layout.h | |
| parent | bbeae5b05ef6e40bf54db05ceb8635824153b9e2 (diff) | |
mm: fold page->_last_nid into page->flags where possible
page->_last_nid fits into page->flags on 64-bit. The unlikely 32-bit
NUMA configuration with NUMA Balancing will still need an extra page
field. As Peter notes "Completely dropping 32bit support for
CONFIG_NUMA_BALANCING would simplify things, but it would also remove
the warning if we grow enough 64bit only page-flags to push the last-cpu
out."
[mgorman@suse.de: minor modifications]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Simon Jeons <simon.jeons@gmail.com>
Cc: Wanpeng Li <liwanp@linux.vnet.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/page-flags-layout.h')
| -rw-r--r-- | include/linux/page-flags-layout.h | 33 |
1 files changed, 25 insertions, 8 deletions
diff --git a/include/linux/page-flags-layout.h b/include/linux/page-flags-layout.h index 316805d6ba1b..93506a114034 100644 --- a/include/linux/page-flags-layout.h +++ b/include/linux/page-flags-layout.h @@ -32,15 +32,16 @@ /* * page->flags layout: * - * There are three possibilities for how page->flags get - * laid out. The first is for the normal case, without - * sparsemem. The second is for sparsemem when there is - * plenty of space for node and section. The last is when - * we have run out of space and have to fall back to an - * alternate (slower) way of determining the node. + * There are five possibilities for how page->flags get laid out. The first + * pair is for the normal case without sparsemem. The second pair is for + * sparsemem when there is plenty of space for node and section information. + * The last is when there is insufficient space in page->flags and a separate + * lookup is necessary. * - * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | - * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | + * No sparsemem or sparsemem vmemmap: | NODE | ZONE | ... | FLAGS | + * " plus space for last_nid: | NODE | ZONE | LAST_NID ... | FLAGS | + * classic sparse with space for node:| SECTION | NODE | ZONE | ... | FLAGS | + * " plus space for last_nid: | SECTION | NODE | ZONE | LAST_NID ... | FLAGS | * classic sparse no space for node: | SECTION | ZONE | ... | FLAGS | */ #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP) @@ -60,6 +61,18 @@ #define NODES_WIDTH 0 #endif +#ifdef CONFIG_NUMA_BALANCING +#define LAST_NID_SHIFT NODES_SHIFT +#else +#define LAST_NID_SHIFT 0 +#endif + +#if SECTIONS_WIDTH+ZONES_WIDTH+NODES_SHIFT+LAST_NID_SHIFT <= BITS_PER_LONG - NR_PAGEFLAGS +#define LAST_NID_WIDTH LAST_NID_SHIFT +#else +#define LAST_NID_WIDTH 0 +#endif + /* * We are going to use the flags for the page to node mapping if its in * there. This includes the case where there is no node, so it is implicit. @@ -68,4 +81,8 @@ #define NODE_NOT_IN_PAGE_FLAGS #endif +#if defined(CONFIG_NUMA_BALANCING) && LAST_NID_WIDTH == 0 +#define LAST_NID_NOT_IN_PAGE_FLAGS +#endif + #endif /* _LINUX_PAGE_FLAGS_LAYOUT */ |