The patch titled
Subject: mm: page_alloc: reduce unnecessary binary search in early_pfn_valid()
has been added to the -mm tree. Its filename is
mm-page_alloc-reduce-unnecessary-binary-search-in-early_pfn_valid.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-page_alloc-reduce-unnecessary-binary-search-in-early_pfn_valid.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-reduce-unnecessary-binary-search-in-early_pfn_valid.patch
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------------------------------------------------------
From: Jia He <jia.he@xxxxxxxxxxxxxxxx>
Subject: mm: page_alloc: reduce unnecessary binary search in early_pfn_valid()
b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where
possible") optimized the loop in memmap_init_zone(). But there is still
some room for improvement. E.g. in early_pfn_valid(), if pfn and pfn+1
are in the same memblock region, we can record the last returned memblock
region index and check whether pfn++ is still in the same region.
Currently it only improve the performance on arm/arm64 and will have no
impact on other arches.
For the performance improvement, after this set, I can see the time
overhead of memmap_init() is reduced from 27956us to 13537us in my armv8a
server(QDF2400 with 96G memory, pagesize 64k).
Link: http://lkml.kernel.org/r/1530867675-9018-7-git-send-email-hejianet@xxxxxxxxx
Signed-off-by: Jia He <jia.he@xxxxxxxxxxxxxxxx>
Cc: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Daniel Vacek <neelx@xxxxxxxxxx>
Cc: Eugeniu Rosca <erosca@xxxxxxxxxxxxxx>
Cc: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Kemi Wang <kemi.wang@xxxxxxxxx>
Cc: Laura Abbott <labbott@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Nikolay Borisov <nborisov@xxxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Petr Tesarik <ptesarik@xxxxxxxx>
Cc: Philip Derrin <philip@cog.systems>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxx>
Cc: Vladimir Murzin <vladimir.murzin@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff -puN include/linux/mmzone.h~mm-page_alloc-reduce-unnecessary-binary-search-in-early_pfn_valid include/linux/mmzone.h
--- a/include/linux/mmzone.h~mm-page_alloc-reduce-unnecessary-binary-search-in-early_pfn_valid
+++ a/include/linux/mmzone.h
@@ -1267,11 +1267,16 @@ static inline int pfn_present(unsigned l
#define pfn_to_nid(pfn) (0)
#endif
-#define early_pfn_valid(pfn) pfn_valid(pfn)
#ifdef CONFIG_HAVE_MEMBLOCK_PFN_VALID
extern ulong memblock_next_valid_pfn(ulong pfn);
#define next_valid_pfn(pfn) memblock_next_valid_pfn(pfn)
-#endif
+
+extern int pfn_valid_region(ulong pfn);
+#define early_pfn_valid(pfn) pfn_valid_region(pfn)
+#else
+#define early_pfn_valid(pfn) pfn_valid(pfn)
+#endif /*CONFIG_HAVE_ARCH_PFN_VALID*/
+
void sparse_init(void);
#else
#define sparse_init() do {} while (0)
_
Patches currently in -mm which might be from jia.he@xxxxxxxxxxxxxxxx are
arm-arm64-introduce-config_have_memblock_pfn_valid.patch
mm-page_alloc-remain-memblock_next_valid_pfn-on-arm-arm64.patch
mm-page_alloc-reduce-unnecessary-binary-search-in-memblock_next_valid_pfn.patch
mm-memblock-introduce-memblock_search_pfn_regions.patch
mm-memblock-introduce-pfn_valid_region.patch
mm-page_alloc-reduce-unnecessary-binary-search-in-early_pfn_valid.patch
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