Subject: [merged] numa-use-last_cpupid_shift-to-calculate-last_cpupid_mask.patch removed from -mm tree
To: srikar@xxxxxxxxxxxxxxxxxx,aneesh.kumar@xxxxxxxxxxxxxxxxxx,benh@xxxxxxxxxxxxxxxxxxx,mel@xxxxxxxxx,paulus@xxxxxxxxx,peterz@xxxxxxxxxxxxx,pingfank@xxxxxxxxxxxxxxxxxx,mm-commits@xxxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 08 Apr 2014 13:59:41 -0700
The patch titled
Subject: numa: use LAST_CPUPID_SHIFT to calculate LAST_CPUPID_MASK
has been removed from the -mm tree. Its filename was
numa-use-last_cpupid_shift-to-calculate-last_cpupid_mask.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Subject: numa: use LAST_CPUPID_SHIFT to calculate LAST_CPUPID_MASK
LAST_CPUPID_MASK is calculated using LAST_CPUPID_WIDTH. However
LAST_CPUPID_WIDTH itself can be 0. (when LAST_CPUPID_NOT_IN_PAGE_FLAGS is
set). In such a case LAST_CPUPID_MASK turns out to be 0.
But with recent commit 1ae71d0319: (mm: numa: bugfix for
LAST_CPUPID_NOT_IN_PAGE_FLAGS) if LAST_CPUPID_MASK is 0,
page_cpupid_xchg_last() and page_cpupid_reset_last() causes
page->_last_cpupid to be set to 0.
This causes performance regression. Its almost as if numa_balancing is
off.
Fix LAST_CPUPID_MASK by using LAST_CPUPID_SHIFT instead of
LAST_CPUPID_WIDTH.
Some performance numbers and perf stats with and without the fix.
(3.14-rc6)
----------
numa01
Performance counter stats for '/usr/bin/time -f %e %S %U %c %w -o start_bench.out -a ./numa01':
12,27,462 cs [100.00%]
2,41,957 migrations [100.00%]
1,68,01,713 faults [100.00%]
7,99,35,29,041 cache-misses
98,808 migrate:mm_migrate_pages [100.00%]
1407.690148814 seconds time elapsed
numa02
Performance counter stats for '/usr/bin/time -f %e %S %U %c %w -o start_bench.out -a ./numa02':
63,065 cs [100.00%]
14,364 migrations [100.00%]
2,08,118 faults [100.00%]
25,32,59,404 cache-misses
12 migrate:mm_migrate_pages [100.00%]
63.840827219 seconds time elapsed
(3.14-rc6 with fix)
-------------------
numa01
Performance counter stats for '/usr/bin/time -f %e %S %U %c %w -o start_bench.out -a ./numa01':
9,68,911 cs [100.00%]
1,01,414 migrations [100.00%]
88,38,697 faults [100.00%]
4,42,92,51,042 cache-misses
4,25,060 migrate:mm_migrate_pages [100.00%]
685.965331189 seconds time elapsed
numa02
Performance counter stats for '/usr/bin/time -f %e %S %U %c %w -o start_bench.out -a ./numa02':
17,543 cs [100.00%]
2,962 migrations [100.00%]
1,17,843 faults [100.00%]
11,80,61,644 cache-misses
12,358 migrate:mm_migrate_pages [100.00%]
20.380132343 seconds time elapsed
Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: Liu Ping Fan <pingfank@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mm.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN include/linux/mm.h~numa-use-last_cpupid_shift-to-calculate-last_cpupid_mask include/linux/mm.h
--- a/include/linux/mm.h~numa-use-last_cpupid_shift-to-calculate-last_cpupid_mask
+++ a/include/linux/mm.h
@@ -695,7 +695,7 @@ void do_set_pte(struct vm_area_struct *v
#define ZONES_MASK ((1UL << ZONES_WIDTH) - 1)
#define NODES_MASK ((1UL << NODES_WIDTH) - 1)
#define SECTIONS_MASK ((1UL << SECTIONS_WIDTH) - 1)
-#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_WIDTH) - 1)
+#define LAST_CPUPID_MASK ((1UL << LAST_CPUPID_SHIFT) - 1)
#define ZONEID_MASK ((1UL << ZONEID_SHIFT) - 1)
static inline enum zone_type page_zonenum(const struct page *page)
_
Patches currently in -mm which might be from srikar@xxxxxxxxxxxxxxxxxx are
origin.patch
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