[PATCH] mm: init: Report on last-nid information stored inpage->flags

From: Mel Gorman
Date: Wed Jan 23 2013 - 08:18:01 EST


Answering the question "how much space remains in the page->flags" is
time-consuming. mminit_loglevel can help answer the question but it does
not take last_nid information into account. This patch corrects it and
while there it corrects the messages related to page flag usage, pgshifts
and node/zone id. When applied the relevant output looks something like
this but will depend on the kernel configuration.

[ 0.000000] mminit::pageflags_layout_widths Section 0 Node 9 Zone 2 Lastnid 9 Flags 25
[ 0.000000] mminit::pageflags_layout_shifts Section 19 Node 9 Zone 2 Lastnid 9
[ 0.000000] mminit::pageflags_layout_pgshifts Section 0 Node 55 Zone 53 Lastnid 44
[ 0.000000] mminit::pageflags_layout_nodezoneid Node/Zone ID: 64 -> 53
[ 0.000000] mminit::pageflags_layout_usage location: 64 -> 44 layout 44 -> 25 unused 25 -> 0 page-flags

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
---
mm/mm_init.c | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/mm/mm_init.c b/mm/mm_init.c
index 1ffd97a..c280a02 100644
--- a/mm/mm_init.c
+++ b/mm/mm_init.c
@@ -69,34 +69,41 @@ void __init mminit_verify_pageflags_layout(void)
unsigned long or_mask, add_mask;

shift = 8 * sizeof(unsigned long);
- width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH;
+ width = shift - SECTIONS_WIDTH - NODES_WIDTH - ZONES_WIDTH - LAST_NID_SHIFT;
mminit_dprintk(MMINIT_TRACE, "pageflags_layout_widths",
- "Section %d Node %d Zone %d Flags %d\n",
+ "Section %d Node %d Zone %d Lastnid %d Flags %d\n",
SECTIONS_WIDTH,
NODES_WIDTH,
ZONES_WIDTH,
+ LAST_NID_WIDTH,
NR_PAGEFLAGS);
mminit_dprintk(MMINIT_TRACE, "pageflags_layout_shifts",
- "Section %d Node %d Zone %d\n",
+ "Section %d Node %d Zone %d Lastnid %d\n",
SECTIONS_SHIFT,
NODES_SHIFT,
- ZONES_SHIFT);
- mminit_dprintk(MMINIT_TRACE, "pageflags_layout_offsets",
- "Section %lu Node %lu Zone %lu\n",
+ ZONES_SHIFT,
+ LAST_NID_SHIFT);
+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_pgshifts",
+ "Section %lu Node %lu Zone %lu Lastnid %lu\n",
(unsigned long)SECTIONS_PGSHIFT,
(unsigned long)NODES_PGSHIFT,
- (unsigned long)ZONES_PGSHIFT);
- mminit_dprintk(MMINIT_TRACE, "pageflags_layout_zoneid",
- "Zone ID: %lu -> %lu\n",
- (unsigned long)ZONEID_PGOFF,
- (unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT));
+ (unsigned long)ZONES_PGSHIFT,
+ (unsigned long)LAST_NID_PGSHIFT);
+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodezoneid",
+ "Node/Zone ID: %lu -> %lu\n",
+ (unsigned long)(ZONEID_PGOFF + ZONEID_SHIFT),
+ (unsigned long)ZONEID_PGOFF);
mminit_dprintk(MMINIT_TRACE, "pageflags_layout_usage",
- "location: %d -> %d unused %d -> %d flags %d -> %d\n",
+ "location: %d -> %d layout %d -> %d unused %d -> %d page-flags\n",
shift, width, width, NR_PAGEFLAGS, NR_PAGEFLAGS, 0);
#ifdef NODE_NOT_IN_PAGE_FLAGS
mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
"Node not in page flags");
#endif
+#ifdef LAST_NID_NOT_IN_PAGE_FLAGS
+ mminit_dprintk(MMINIT_TRACE, "pageflags_layout_nodeflags",
+ "Last nid not in page flags");
+#endif

if (SECTIONS_WIDTH) {
shift -= SECTIONS_WIDTH;
--
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