From mboxrd@z Thu Jan 1 00:00:00 1970 From: hejianet@gmail.com (Jia He) Date: Sun, 1 Apr 2018 19:30:36 -0700 Subject: [PATCH v5 5/5] mm: page_alloc: reduce unnecessary binary search in early_pfn_valid() In-Reply-To: <1522636236-12625-1-git-send-email-hejianet@gmail.com> References: <1522636236-12625-1-git-send-email-hejianet@gmail.com> Message-ID: <1522636236-12625-6-git-send-email-hejianet@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Commit 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 check pfn++ is still in the same region. Currently it only improve the performance on arm64 and will have no impact on other arches. Signed-off-by: Jia He --- include/linux/mmzone.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index f9c0c46..079f468 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1268,9 +1268,14 @@ static inline int pfn_present(unsigned long pfn) }) #else #define pfn_to_nid(pfn) (0) -#endif +#endif /*CONFIG_NUMA*/ +#ifdef CONFIG_HAVE_ARCH_PFN_VALID +#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) -- 2.7.4