From mboxrd@z Thu Jan 1 00:00:00 1970 From: hejianet@gmail.com (Jia He) Date: Wed, 11 Apr 2018 00:21:56 -0700 Subject: [PATCH v8 5/6] arm: arm64: introduce pfn_valid_region() In-Reply-To: <1523431317-30612-1-git-send-email-hejianet@gmail.com> References: <1523431317-30612-1-git-send-email-hejianet@gmail.com> Message-ID: <1523431317-30612-6-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(), we can record the last returned memblock region. If current pfn and last pfn are in the same memory region, we needn't do the unnecessary binary searches because memblock_is_nomap is the same result for whole memory region. Signed-off-by: Jia He --- include/linux/early_pfn.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/include/linux/early_pfn.h b/include/linux/early_pfn.h index f9e40c3..9609391 100644 --- a/include/linux/early_pfn.h +++ b/include/linux/early_pfn.h @@ -51,5 +51,29 @@ ulong __init_memblock memblock_next_valid_pfn(ulong pfn) return PHYS_PFN(regions[early_region_idx].base); } EXPORT_SYMBOL(memblock_next_valid_pfn); + +int pfn_valid_region(ulong pfn) +{ + ulong start_pfn, end_pfn; + struct memblock_type *type = &memblock.memory; + struct memblock_region *regions = type->regions; + + if (early_region_idx != -1) { + start_pfn = PFN_DOWN(regions[early_region_idx].base); + end_pfn = PFN_DOWN(regions[early_region_idx].base + + regions[early_region_idx].size); + + if (pfn >= start_pfn && pfn < end_pfn) + return !memblock_is_nomap( + ®ions[early_region_idx]); + } + + early_region_idx = memblock_search_pfn_regions(pfn); + if (early_region_idx == -1) + return false; + + return !memblock_is_nomap(®ions[early_region_idx]); +} +EXPORT_SYMBOL(pfn_valid_region); #endif /*CONFIG_HAVE_MEMBLOCK_PFN_VALID*/ #endif /*__EARLY_PFN_H*/ -- 2.7.4